On behalf of the boards of directors of Banc of California, Inc., a Maryland corporation (“BANC”), and PacWest Bancorp, a Delaware corporation (“PACW”), we are pleased to enclose the accompanying joint proxy statement/prospectus relating to the proposed combination of BANC and PACW. We are requesting that you take certain actions as a holder of BANC common stock (a “BANC stockholder”) or as a holder of PACW common stock (a “PACW stockholder”).

On July 25, 2023, BANC, PACW and Cal Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of BANC (“Merger Sub”), entered into an Agreement and Plan of Merger (as it may be amended, modified or supplemented from time to time in accordance with its terms, the “merger agreement”), pursuant to which, on the terms and subject to the conditions set forth in the merger agreement, BANC and PACW have agreed to combine their respective businesses through a series of mergers. The transaction will create the premier relationship-focused business bank in California with approximately $36.1 billion in assets, $25.3 billion in total loans, $30.5 billion in total deposits and more than 70 branches in California.

On the terms and subject to the conditions set forth in the merger agreement, at the closing, Merger Sub will merge with and into PACW (the “first merger”), with PACW as the surviving entity. Immediately following the first merger, PACW will merge with and into BANC (the “second merger” and together with the first merger, the “mergers”), with BANC as the surviving corporation (the “combined company” and certain references to “BANC” herein refer to the combined company following the second merger, as the context requires). Promptly following the second merger, Pacific Western Bank, a California-chartered non-member bank (“PACW Bank”) and, as of immediately prior to the second merger, a wholly-owned subsidiary of PACW, will become a member bank of the Federal Reserve System (the “FRS Membership”). Promptly following the effectiveness of the FRS Membership, Banc of California, National Association, a national banking association and a wholly-owned subsidiary of BANC (“BANC N.A.”), will merge with and into PACW Bank (the “bank merger” and together with the mergers, the “combination”), with PACW Bank continuing as the surviving bank (the “surviving bank”). Following the bank merger, the surviving bank will operate under the “Banc of California” name and brand.

In the first merger, the PACW stockholders will be entitled to receive 0.6569 of a share of BANC common stock for each share of PACW common stock (the “exchange ratio”) they own, subject to certain exceptions. Although the number of shares of BANC common stock that PACW stockholders will be entitled to receive per share of PACW common stock is fixed, the market value of the merger consideration will fluctuate with the market price of BANC common stock and will not be known at the time PACW stockholders vote on the merger agreement. Based on the closing price of BANC common stock on the New York Stock Exchange (the “NYSE”) on July 24, 2023, the last trading day before the public announcement of the mergers, the exchange ratio represented an implied value of approximately $8.64 for each share of PACW common stock. Based on the closing price of BANC common stock on the NYSE on [ ], 2023, the last practicable trading day before the date of the accompanying joint proxy statement/prospectus, of $[ ], the exchange ratio represented an implied value of approximately $[ ] for each share of PACW common stock. The value of the BANC common stock at the time of completion of the mergers could be greater than, less than or the same as the value of BANC common stock on the date of the accompanying joint proxy statement/prospectus or the date of the special meeting of BANC or PACW. We urge you to obtain current market quotations of BANC common stock (NYSE trading symbol “BANC”) and PACW common stock (Nasdaq Global Select Market (“Nasdaq”) trading symbol “PACW”).

In the second merger, each outstanding share of 7.75% Fixed Rate Reset Non-Cumulative Perpetual Preferred Stock, Series A, of PACW (the “PACW preferred stock” and such holders the “PACW preferred stockholders”) will be converted into the right to receive one share of a newly created series of preferred stock of BANC (the “new BANC preferred stock”) having such powers, preferences and rights, and such qualifications, limitations and restrictions, taken as a whole, that are not materially less favorable to the PACW preferred stockholders than the existing powers, preferences, rights, qualifications and limitations of

the PACW preferred stock. Likewise, following the completion of the mergers, each outstanding PACW depositary share representing a 1/40th interest in a share of PACW preferred stock will become a BANC depositary share representing a 1/40th interest in a share of new BANC preferred stock. The PACW depositary shares are currently listed on Nasdaq under the symbol “PACWP.” The BANC depositary shares representing a 1/40th interest in a share of new BANC preferred stock are expected to be listed on the NYSE upon completion of the mergers.

Immediately following completion of the mergers, BANC stockholders will continue to own the shares of BANC common stock held by the BANC stockholders immediately prior to the completion of the mergers.

Concurrently with its entry into the merger agreement, BANC entered into separate investment agreements (the “investment agreements”), each dated as of July 25, 2023, with (x) affiliates of funds managed by Warburg Pincus LLC (the “Warburg Investors”) and (y) certain investment vehicles sponsored, managed or advised by Centerbridge Partners, L.P. and its affiliates (the “Centerbridge Investor” and, together with the Warburg Investors, the “Investors”). On the terms and subject to the conditions set forth in the investment agreements, at the closing of the investments (as defined below), the Investors will invest an aggregate of $400 million in exchange for the sale and issuance by BANC of approximately (a) 21.8 million shares of BANC common stock and (b) 10.8 million shares of a new class of non-voting, common-equivalent stock of BANC (“BANC NVCE stock”), in each case, at a purchase price of $12.30 per share. In addition, the Warburg Investors will receive warrants to purchase approximately 15.9 million shares of BANC NVCE stock, and the Centerbridge Investor will receive warrants to purchase approximately 3.0 million shares of BANC common stock, each with an exercise price of $15.375 per share, a 25% premium to the price paid by the Investors for BANC common stock and BANC NVCE stock (collectively, the “warrants” and together with the BANC common stock and the BANC NVCE stock to be issued pursuant to the investment agreements, the “investments”). The warrants carry a term of seven years but are subject to mandatory exercise when the market price of BANC common stock reaches or exceeds $24.60 for 20 or more trading days during any 30-consecutive trading day period, a 100% premium to the price paid by the Investors for BANC common stock and BANC NVCE stock.

We expect that the mergers, taken together, will qualify as a “reorganization” within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended (the “Code”). Accordingly, PACW stockholders generally will not recognize any gain or loss for U.S. federal income tax purposes on the exchange of shares of PACW common stock for BANC common stock in the first merger, except with respect to any cash received by PACW stockholders in lieu of fractional shares of BANC common stock.

Based on the number of shares of PACW common stock outstanding or reserved for issuance as of August 23, 2023, BANC expects to issue approximately 77.9 million shares of BANC common stock to PACW stockholders and approximately 1 million shares of BANC common stock to the holders of PACW restricted stock awards in the aggregate in the first merger. Upon completion of the proposed transaction, (a) the shares issued to PACW stockholders in the first merger are expected to represent approximately 47% of the outstanding shares of the combined company, (b) the shares issued to the Investors in the investments are expected to represent approximately 19% of the outstanding shares of the combined company and (c) the shares of BANC common stock that are outstanding immediately prior to completion of the first merger are expected to represent approximately 34% of the outstanding shares of the combined company.

BANC and PACW will each hold a special meeting of its respective stockholders in connection with the mergers. At its special meeting, in addition to other business, BANC will ask its stockholders to approve the issuance of shares of BANC common stock to PACW stockholders pursuant to the merger agreement and BANC common stock, shares of BANC NVCE stock and warrants pursuant to the investment agreements (collectively, the “BANC issuance”). At its special meeting, in addition to other business, PACW will ask its stockholders to adopt the merger agreement. Information about these meetings, the mergers and the investments is contained in this document. We urge you to read this document carefully and in its entirety.

The special meeting of BANC stockholders will be held on [ ], 2023 at [ ], Pacific Time at 3 MacArthur Place, Santa Ana, CA 92707. The special meeting of PACW stockholders will be held on [ ], 2023 at [ ], Mountain Time at Denver Marriott Tech Center, 4900 S. Syracuse St, Denver, CO 80237.

Each of our boards of directors unanimously recommends that holders of BANC common stock and PACW common stock vote “FOR” each of the proposals to be considered at the respective special meetings.

The accompanying joint proxy statement/prospectus provides you with detailed information about the merger agreement and the investment agreements and the transactions contemplated thereby. It also contains or references information about BANC and PACW and certain related matters. You are encouraged to read the accompanying joint proxy statement/prospectus carefully and in its entirety. In

particular, you should read the section entitled “Risk Factors” beginning on page 36 for a discussion of the risks you should consider in evaluating the proposed transaction and how it will affect you. You can also obtain information about BANC and PACW from documents that have been filed with the Securities and Exchange Commission that are either incorporated by reference into or attached to the accompanying joint proxy statement/prospectus.

On behalf of BANC and PACW, thank you for your prompt attention to this important matter.

Sincerely,

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued in connection with the first merger or determined if this document is accurate or complete. Any representation to the contrary is a criminal offense.

The securities to be issued in the first merger are not savings or deposit accounts or other obligations of any bank or non-bank subsidiary of either BANC or PACW, and they are not insured by the Federal Deposit Insurance Corporation or any other governmental agency.

The accompanying joint proxy statement/prospectus is dated [ ], 2023, and is first being mailed to BANC stockholders and PACW stockholders on or about [ ], 2023.

The accompanying joint proxy statement/prospectus includes important business and financial information about (a) PACW from documents previously filed with the U.S. Securities and Exchange Commission (the “SEC”) that have been attached as annexes to the accompanying joint proxy statement/prospectus and (b) BANC from documents previously filed with the SEC that are incorporated by reference into the accompanying joint proxy statement/prospectus. This information is available to you without charge upon your written or oral request. You can obtain the documents, including the documents regarding BANC that are incorporated by reference in such document through (i) the SEC website at http://www.sec.gov, (ii) BANC’s website at https://investors.bancofcal.com, under the heading “Financials and Filings” or (iii) PACW’s website at www.pacwestbancorp.com, under the heading “SEC Filings,” or by requesting them in writing, by email or by telephone, at the appropriate address below. Except for the documents regarding PACW attached as annexes to the accompanying joint proxy statement/prospectus and the documents regarding BANC incorporated by reference in such document, the information contained on, or that may be accessed through, the respective websites of the SEC, PACW and BANC is not incorporated by reference into, and is not a part of, the accompanying joint proxy statement/prospectus.

You will not be charged for any of these documents that you request. To obtain timely delivery of these documents, you must request them no later than five business days before the date of the applicable special meeting. This means that holders of BANC common stock requesting documents must do so by [ ], 2023, in order to receive them before the BANC special meeting, and holders of PACW common stock requesting documents must do so by [ ], 2023, in order to receive them before the PACW special meeting.

The accompanying joint proxy statement/prospectus attaches as annexes documents that PACW previously filed with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), as set forth below. Any statement contained in such a document shall be deemed to be modified or superseded for purposes of the accompanying joint proxy statement/prospectus to the extent that a statement contained in the accompanying joint proxy statement/prospectus or in an annex hereto consisting of a document filed with the SEC subsequent to such document modifies or replaces such statement.

PACW Filings:

You should rely only on the information contained in, attached to or incorporated by reference into the accompanying joint proxy statement/prospectus. No one has been authorized to provide you with information that is different from that contained in, attached to or incorporated by reference into, such document. The accompanying joint proxy statement/prospectus is dated [ ], 2023, and you should assume that the information in this document is accurate only as of such date. You should assume that the information incorporated by reference into such document or attached as an annex to such document is accurate as of the date of such

document. Neither the mailing of the accompanying joint proxy statement/prospectus to holders of BANC common stock or holders of PACW common stock, nor the issuance by BANC of shares of BANC common stock or other securities pursuant to the merger agreement or investment agreements, will create any implication to the contrary.

The accompanying joint proxy statement/prospectus document does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy, in any jurisdiction to or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction. Except where the context otherwise indicates, information contained in, or incorporated by reference into, the accompanying joint proxy statement/prospectus regarding PACW has been provided by PACW and information contained in, or incorporated by reference into, the accompanying joint proxy statement/prospectus regarding BANC has been provided by BANC.

See the section entitled “Where You Can Find More Information” beginning on page 216 of the accompanying joint proxy statement/prospectus for further information.

 

To BANC Stockholders:

On July 25, 2023, Banc of California, Inc., a Maryland corporation (“BANC”), Cal Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of BANC (“Merger Sub”), and PacWest Bancorp, a Delaware corporation (“PACW”), entered into an Agreement and Plan of Merger (as it may be amended, modified or supplemented from time to time in accordance with its terms, the “merger agreement”). A copy of the merger agreement is attached as Annex A to the accompanying joint proxy statement/prospectus.

Concurrently with its entry into the merger agreement, BANC entered into separate investment agreements (the “investment agreements”), each dated as of July 25, 2023, with (a) affiliates of funds managed by Warburg Pincus LLC (the “Warburg Investors”) and (b) certain investment vehicles sponsored, managed or advised by Centerbridge Partners, L.P. and its affiliates (the “Centerbridge Investor” and, together with the Warburg Investors, the “Investors”). Copies of the investment agreements are attached as Annex B and Annex C to the accompanying joint proxy statement/prospectus.

NOTICE IS HEREBY GIVEN that a special meeting of holders of BANC common stock (such holders the “BANC stockholders” and such meeting the “BANC special meeting”) will be held on [ ], 2023 at [ ], Pacific Time at 3 MacArthur Place, Santa Ana, CA 92707.

At the BANC special meeting, you will be asked to vote on the following matters:

The board of directors of BANC (the “BANC board of directors”) has fixed the close of business on [ ], 2023 as the record date for the BANC special meeting. Only holders of record of BANC common stock as of the close of business on the BANC record date are entitled to notice of the BANC special meeting or any adjournment or postponement thereof. Only holders of record of BANC common stock will be entitled to vote at the BANC special meeting or any adjournment or postponement thereof.

BANC stockholders are not entitled to dissenters’ rights in connection with the mergers under the Maryland General Corporation Law.

The BANC board of directors unanimously recommends that BANC stockholders vote “FOR” the BANC issuance proposal, “FOR” the BANC incentive plan proposal, “FOR” the BANC exemption amendment proposal and “FOR” the BANC adjournment proposal.

Your vote is important. We cannot complete the transactions contemplated by the merger agreement and the investment agreements unless BANC stockholders approve the BANC issuance proposal. However, the consummation of the mergers and the closing of the transactions contemplated by the investment agreements is not conditioned upon approval of the BANC incentive plan proposal, the BANC exemption amendment proposal or the BANC adjournment proposal. The affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting is required to approve the BANC issuance proposal, the BANC incentive plan proposal and the BANC adjournment proposal. The affirmative vote of the holders of a majority of the outstanding shares of BANC common stock entitled to vote on the proposal is required to approve the BANC exemption amendment proposal.

Whether or not you plan to attend the BANC special meeting, we urge you to please promptly complete, sign, date and return the accompanying proxy card in the enclosed postage-paid envelope. You may also vote by telephone or through the internet as described in the instructions included with the accompanying proxy card. If your shares are held in the name of a bank, broker, trustee or other nominee, please follow the instructions on the voting instruction card furnished by such bank, broker, trustee or other nominee.

[ ], 2023

 

Date: [  ], 2023

The following are some questions that you may have about the mergers, the investments, the BANC special meeting or the PACW special meeting (each as defined below), and brief answers to those questions. We urge you to read carefully the remainder of this joint proxy statement/prospectus because the information in this section does not provide all of the information that might be important to you with respect to the mergers, the investments, the BANC special meeting or the PACW special meeting. Additional important information is also contained in the documents incorporated by reference into this joint proxy statement/prospectus and in the annexes to this joint proxy statement/prospectus. See the section entitled “Where You Can Find More Information” beginning on page 216.

In this joint proxy statement/prospectus, unless the context otherwise requires:

In order to complete the mergers (as hereinafter defined) and the investments (as hereinafter defined), among other things:

BANC stockholders will also be asked to: (a) approve a proposal to adopt the A&R 2018 Plan, pursuant to which the combined company will be able to make grants of equity-based awards to employees, officers, directors and consultants of the combined company following the closing of the transactions contemplated by the merger agreement (the “BANC incentive plan proposal”); (b) approve a proposal to amend Section F of Article 6 of the BANC charter in a manner to exempt the Warburg Investors and their affiliates (but not any other stockholder of BANC) from the application of Section F of Article 6 (other than paragraph 4 thereof, which deals mainly with the quorum requirement for meetings of BANC stockholders) of the BANC charter (the “BANC exemption amendment proposal”); and (c) approve a proposal to adjourn the special meeting of BANC stockholders (the “BANC special meeting”), if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the BANC special meeting to approve the BANC issuance proposal (the “BANC adjournment proposal”). Approval of the BANC incentive plan proposal, the BANC exemption amendment proposal or the BANC adjournment proposal is not a condition to the completion of the mergers or the investments.

PACW stockholders will also be asked (i) to approve, on a non-binding, advisory basis, the compensation payments that PACW’s named executive officers may receive in connection with the mergers pursuant to agreements or arrangements with PACW (the “PACW compensation proposal”), and (ii) to approve a proposal to adjourn the special meeting of PACW stockholders (the “PACW special meeting”), if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the PACW special meeting to approve the PACW merger proposal (the “PACW adjournment proposal”). Approval of the PACW compensation proposal or the PACW adjournment proposal is not a condition to the completion of the mergers or the investments.

This document is also a prospectus that is being delivered to PACW stockholders because, pursuant to the merger agreement, BANC is (i) offering shares of BANC common stock to PACW stockholders and (ii) issuing shares of new BANC preferred stock to the PACW preferred stockholders.

This joint proxy statement/prospectus contains important information about the mergers, the investments and the other proposals being voted on at the BANC special meeting and PACW special meeting. You should read it carefully and in its entirety. The enclosed materials allow you to have your shares of common stock voted by proxy without attending your special meeting. Your vote is important, and we encourage you to submit your proxy as soon as possible.

mergers, the “combination”), with PACW Bank continuing as the surviving bank (the “surviving bank”). Following the bank merger, the surviving bank will operate under the “Banc of California” name and brand.

At the effective time of the first merger (the “effective time”), holders of PACW common stock issued and outstanding immediately prior to the effective time (except for shares of PACW common stock owned by PACW as treasury stock or owned by PACW, BANC or Merger Sub (subject to certain exceptions)) will be entitled to receive 0.6569 of a share (the “exchange ratio”) of BANC common stock and cash in lieu of any fractional shares (the “merger consideration”).

At the effective time of the second merger (the “second effective time”), each outstanding share of 7.75% Fixed Rate Reset Non-Cumulative Perpetual Preferred Stock, Series A, of PACW (the “PACW preferred stock”) will be converted into the right to receive one share of a newly created series of preferred stock of BANC (the “new BANC preferred stock”) having such powers, preferences and rights, and such qualifications, limitations and restrictions, taken as a whole, that are not materially less favorable to the PACW preferred stockholders than the existing powers, preferences, rights, qualifications and limitations of the PACW preferred stock. Likewise, following the completion of the mergers, each outstanding PACW depositary share representing a 1/40th interest in a share of PACW preferred stock will become a BANC depositary share representing a 1/40th interest in a share of new BANC preferred stock (“BANC depositary share”). A form of the Articles Supplementary relating to the new BANC preferred stock is attached hereto as Annex I.

In this joint proxy statement/prospectus, we refer to the closing of the (a) first merger as the “merger closing” and the date on which the merger closing occurs as the “merger closing date” and (b) second merger as the “closing of the mergers”.

After the effective time, (i) PACW will no longer be a public company, (ii) PACW common stock will be delisted from Nasdaq and will cease to be publicly traded, and (iii) PACW common stock and PACW depositary shares will be deregistered under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Immediately after the second effective time, BANC stockholders will continue to own their existing shares of BANC common stock and PACW will cease to exist. See the information provided in the section entitled “The Merger Agreement—Structure of the Mergers” beginning on page 128 and the merger agreement attached as Annex A for more information about the mergers.

Concurrently with its entry into the merger agreement, BANC entered into separate investment agreements, each dated as of July 25, 2023, with the Warburg Investors (the “Warburg investment agreement”) and the Centerbridge Investor (the “Centerbridge investment agreement” and, together with the Warburg investment agreement, the “investment agreements”). On the terms and subject to the conditions set forth in the investment agreements, the Investors will invest an aggregate of $400 million in exchange for the sale and issuance by BANC of approximately (a) 21.8 million shares of BANC common stock and (b) 10.8 million shares of a new class of non-voting, common-equivalent stock of BANC (“BANC NVCE stock”), in each case, at a purchase price of $12.30 per share. In addition, the Warburg Investors will receive warrants to purchase approximately 15.9 million shares of BANC NVCE stock, and the Centerbridge Investor will receive warrants to purchase approximately 3.0 million shares of BANC common stock, each with an exercise price of $15.375 per share, a 25% premium to the price paid by the Investors for BANC common stock and BANC NVCE stock (collectively, the “warrants” and together with the BANC common stock and the BANC NVCE stock to be issued pursuant to the investment agreements, the “investments”). The warrants carry a term of seven years but are subject to mandatory exercise when the market price of BANC common stock reaches or exceeds $24.60 for 20 or more trading days during any 30-consecutive trading day period, a 100% premium to the price paid by the Investors for BANC common stock and BANC NVCE stock. Additionally, following the ninetieth (90th) day after the date of the closing of the Warburg investment (the “Warburg investment closing”) and upon the written request of the Warburg Investors (or certain permitted transferees), the Warburg Investors (or such transferee) may exchange all or a portion of such person’s shares of BANC NVCE stock (including shares of BANC NVCE stock for which the warrants issued to the Warburg Investors may be exercised) for shares of BANC common stock or non-voting common stock of BANC, subject to certain conditions. See the section entitled “ Investment Agreements—Additional Warburg Investors Rights and Covenants—Covenants Regarding BANC NVCE Stock ” beginning on page 156 for more information. In this joint proxy statement/prospectus, we refer to the closing of the investments as the “investment closing.”

The investments are contingent upon the merger closing in accordance with the terms of the merger agreement and are subject to the satisfaction or waiver of certain other closing conditions. See the information provided in the section entitled “The Investment Agreements” beginning on page 150 and the investment agreements attached as Annex B and Annex C for more information about the investments.

The PACW special meeting will be held on [   ], 2023 at [   ], Mountain Time at Denver Marriott Tech Center, 4900 S. Syracuse St, Denver, CO 80237.

Even if you plan to attend your respective company’s special meeting, BANC and PACW recommend that you vote your shares in advance as described below so that your vote will be counted if you later decide not to attend or become unable to attend the applicable special meeting. See the section entitled “—Q: How can I vote my shares without attending my respective special meeting?” beginning on page 9.

At the PACW special meeting, PACW stockholders will be asked to consider and vote on the following proposals:

In order to complete the mergers and the investments, among other things, BANC stockholders must approve the BANC issuance proposal, and PACW stockholders must approve the PACW merger proposal. None of the approvals of the BANC incentive plan proposal, BANC exemption amendment proposal, BANC adjournment proposal, PACW compensation proposal or PACW adjournment proposal is a condition to the obligations of BANC or PACW to complete the mergers or of BANC or the Investors to complete the investments.

(after taking into account all shares of PACW common stock held by such holder immediately prior to the completion of the first merger and rounded to the nearest thousandth when expressed in decimal form) of BANC common stock that such PACW stockholder would otherwise be entitled to receive.

In the second merger, each outstanding share of PACW preferred stock will be converted into the right to receive one share of new BANC preferred stock and each outstanding PACW depositary share will become a BANC depositary share. Upon completion of the second merger, BANC will enter into a deposit agreement with Computershare Inc. and Computershare Trust Company, N.A., jointly acting as depositary thereunder. For more information, see the sections entitled “ Description of New BANC Preferred Stock ” beginning on page 189 and “ Description of the BANC Depositary Shares ” beginning on page 200 .

In considering the recommendations of the BANC board of directors, BANC stockholders should be aware that BANC directors and executive officers may have interests in the mergers that are different from, or in addition to, the interests of BANC stockholders generally. For a more complete description of these interests, see the information provided in the section entitled “The Transactions—Interests of Certain BANC Directors and Executive Officers in the Mergers” beginning on page 115.

In considering the recommendations of the PACW board of directors, PACW stockholders should be aware that PACW directors and executive officers may have interests in the mergers that are different from, or in addition to, the interests of PACW stockholders generally. For a more complete description of these interests, see the information provided in the section entitled “The Transactions—Interests of Certain PACW Directors and Executive Officers in the Mergers” beginning on page 118.

Each holder of record of BANC common stock as of the BANC record date is entitled to cast one vote on each matter properly brought before the BANC special meeting for each share of BANC common stock that such holder owned of record as of the BANC record date; provided, however, that under Section F of Article 6 of the BANC charter, no BANC stockholder who beneficially owns more than ten percent (10%) of the shares of BANC common stock outstanding as of the BANC record date may vote shares held in excess of such amount. As of the close of business on the BANC record date, there were [   ] outstanding shares of BANC common stock held by [   ] holders of record.

Attendance at the BANC special meeting is not required to vote. See below and the section entitled “The BANC Special Meeting—Proxies” beginning on page 49 for instructions on how to vote your shares of BANC common stock without attending the BANC special meeting.

Each holder of record of PACW common stock as of the PACW record date is entitled to cast one vote on each matter properly brought before the PACW special meeting for each share of PACW common stock that such holder owned of record as of the PACW record date. As of the close of business on the PACW record date, there were [   ] outstanding shares of PACW common stock held by [   ] holders of record.

See below and the section entitled “The PACW Special Meeting—Proxies” beginning on page 65 for instructions on how to vote your shares of PACW common stock without attending the PACW special meeting.

meeting for the purpose of determining the presence of a quorum. As it is expected that all proposals to be voted on at the BANC special meeting will be “non-routine” matters, as discussed in the section entitled, “The BANC Special Meeting—Broker Non-Votes,” BANC does not expect any broker non-votes to occur at the BANC special meeting.

BANC Proposal 2: BANC incentive plan proposal. Approval of the BANC incentive plan proposal requires the affirmative vote of a majority of the votes cast by holders of shares of BANC common stock at the BANC special meeting.

BANC Proposal 3: BANC exemption amendment proposal. Approval of the BANC exemption amendment proposal requires the affirmative vote of the holders of a majority of the outstanding shares of BANC common stock entitled to vote on such proposal.

BANC Proposal 4: BANC adjournment proposal. Whether or not a quorum will be present at the meeting, approval of the BANC adjournment proposal requires the affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting.

PACW Proposal 2: PACW compensation proposal. Approval of the PACW compensation proposal requires the affirmative vote of the holders of at least a majority of the shares of PACW common stock present or represented by proxy at the PACW special meeting.

PACW Proposal 3: PACW adjournment proposal. Approval of PACW adjournment proposal requires the affirmative vote of the holders of at least a majority of the shares of PACW common stock present or represented by proxy at the PACW special meeting.

first merger. As of the close of business on the PACW record date, such persons beneficially owned, in the aggregate, [   ] shares of PACW common stock, allowing them to exercise approximately [   ]% of the voting power of PACW common stock (which does not include shares issuable upon the exercise, vesting or settlement of PACW equity-based awards that were not outstanding as of the close of business on the PACW record date).

In addition, each member of the BANC board of directors has entered into a voting agreement with PACW in which such director has agreed to vote all BANC common stock that such director owns and has the power to vote in favor of the BANC issuance proposal and any other matter that is reasonably necessary to be approved by the BANC stockholders to facilitate the consummation of the transactions contemplated by the merger agreement. Each member of the BANC board of directors has also agreed to vote against any proposal made in opposition to the approval of the adoption of the merger agreement or that is otherwise in competition or inconsistent with the transactions contemplated by the merger agreement, against any acquisition proposal and against any proposal, transaction, agreement or amendment to BANC’s organizational documents or other action that is intended to or could reasonably be expected to prevent, impede, interfere with, materially delay, postpone, adversely affect or discourage the consummation of the first merger. As of the close of business on the BANC record date, such persons beneficially owned, in the aggregate, [   ] shares of BANC common stock, allowing them to exercise approximately [   ]% of the voting power of BANC common stock (which does not include shares issuable upon the exercise, vesting or settlement of BANC equity-based awards that were not outstanding as of the close of business on the BANC record date).

Beneficial Owners. If you hold shares in the name of a bank, broker, trustee or other nominee (e.g., in a brokerage or other account in “street name”), then you are a “beneficial owner” of such shares. Please follow the instructions on the voting instruction card furnished by such bank, broker, trustee or other nominee in order to vote such shares.

BANC special meeting. If you are a holder of record of BANC common stock on the BANC record date, you will be able to attend the BANC special meeting, ask questions and vote during the meeting. Each person attending must present a valid, government issued form of identification in order to be admitted to the BANC special meeting. Each stockholder attending also must provide proof of ownership of shares of BANC common stock as of the BANC record date. If you are a record holder, proof of ownership will be established by BANC’s verification of your name against BANC’s list of record holders as of the BANC record date. If you hold your shares through a bank, broker, trustee or other nominee, you must provide one of the following as proof of ownership: (a) account statement showing share ownership as of the BANC record date, (b) a copy of an email that you received with instructions containing a link to the website where the BANC’s proxy materials are available and a valid control number, (c) a valid legal proxy containing a valid control number or a letter from a record holder naming you as proxy, or (d) a letter from the bank, broker, trustee or other nominee through which you hold your shares confirming your ownership as of the BANC record date.

PACW special meeting. All PACW stockholders, including stockholders of record of PACW common stock and PACW stockholders who hold their shares through banks, brokers, trustees or other nominees, are invited to attend the PACW special meeting. PACW stockholders of record on the PACW record date can vote in person at the PACW special meeting. If you are not a PACW stockholder of record on the PACW record date, you must obtain a legal proxy executed in your favor from the record holder of your shares to be able to vote in person at the PACW special meeting. If you plan to attend the PACW special meeting, you must hold your shares in your own name or have a letter from the record holder of your shares confirming your ownership. In addition, you must bring a form of personal photo identification with you in order to be admitted to the meeting. PACW reserves the right to refuse admittance to anyone without proper proof of share ownership or without proper photo identification.

Even if you plan to attend the BANC special meeting or the PACW special meeting, as applicable, BANC and PACW recommend that you vote your shares in advance as described below so that your vote will be counted if you later decide not to or become unable to attend the respective special meeting.

Additional information on attending the special meetings can be found under the section entitled “The BANC Special Meeting—Attending the Special Meeting” on page 48 and under the section entitled “The PACW Special Meeting—Attending the Special Meeting” on page 65.

If you intend to submit your proxy by telephone or via the internet, you must do so by [   ], local time, on the day before your respective company’s special meeting. If you intend to submit your proxy by mail, your completed proxy card must be received prior to your respective company’s special meeting.

Additional information on voting procedures can be found under the section entitled “The BANC Special Meeting—Attending the Special Meeting” on page 48 and under the section entitled “The PACW Special Meeting—Attending the Special Meeting” on page 65.

Each such PACW stockholder is entitled to one vote for each share of PACW common stock held as of the PACW record date. The PACW charter does not contain a limit on voting shares of PACW common stock.

A broker non-vote occurs when (a) a bank, broker, trustee or other nominee has discretionary authority to vote on one or more proposals to be voted on at a meeting of stockholders but is not permitted to vote on other proposals without instructions from the beneficial owner of the shares and (b) the beneficial owner fails to provide the bank, broker, trustee or other nominee with such instructions. Under applicable stock

exchange rules, banks, brokers, trustees and other nominees holding shares in “street name” do not have discretionary voting authority with respect to any of the proposals described in this joint proxy statement/prospectus to be voted at the BANC special meeting or the PACW special meeting. It is expected that all proposals to be voted on at each of the BANC special meeting and the PACW special meeting will be “non-routine” matters, and, as such, if a beneficial owner of shares of BANC common stock or PACW common stock held in “street name” does not give voting instructions to the bank, broker, trustee or other nominee, then those shares will not be counted as present in person or by proxy at the BANC special meeting or PACW special meeting.

Broker non-votes only count toward a quorum if at least one proposal is presented with respect to which the bank, broker, trustee or other nominee has discretionary authority. Since it is expected that all proposals to be voted on at each of the BANC special meeting and the PACW special meeting will be “non-routine” matters, as discussed in the sections entitled, “The BANC Special Meeting—Broker Non-Votes” and “The PACW Special Meeting—Broker Non-Votes,” no broker non-votes are expected to occur at the BANC special meeting or the PACW special meeting.

If you are a beneficial owner of BANC common stock and you do not instruct your bank, broker, trustee or other nominee on how to vote your shares of BANC common stock, your bank, broker, trustee or other nominee will not have authority to vote your shares on the BANC issuance proposal, the BANC incentive plan proposal, the BANC exemption amendment proposal or the BANC adjournment proposal and therefore such shares of BANC common stock will not be counted for purposes of establishing a quorum. Assuming a quorum is present, this will not have any effect on the BANC issuance proposal, the BANC incentive plan proposal or the BANC adjournment proposal and will have the same effect as a vote “AGAINST” the BANC exemption amendment proposal.

If you are a beneficial owner of PACW common stock and you do not instruct your bank, broker, trustee or other nominee on how to vote your shares of PACW common stock, your bank, broker, trustee or other nominee will not have authority to vote your shares of PACW common stock on the PACW merger proposal, the PACW compensation proposal or the PACW adjournment proposal, and therefore such shares of PACW common stock will not be counted for purposes of establishing a quorum. In the case of the PACW merger proposal, this will have the same effect as a vote “AGAINST” the PACW merger proposal. In the case of the PACW compensation proposal and the PACW adjournment proposal, this will have no effect on the outcome of such proposals.

If you intend to submit your proxy by telephone or via the internet, you must do so by [   ], local time, on the day before your respective company’s special meeting. If you intend to submit your proxy by mail, your completed proxy card must be received prior to your respective company’s special meeting.

If you are a beneficial owner and you have instructed a bank, broker, trustee or other nominee to vote your shares, you must follow the directions you receive from your bank, broker, trustee or other nominee in order to change or revoke your vote.

submit the PACW merger proposal to its stockholders even if the PACW board of directors has withdrawn, modified or qualified its recommendation in favor of approving such proposal.

stockholder approval and (f) the consummation of the equity financing occurring substantially concurrently with the merger closing. For more information, see the section entitled “The Merger Agreement—Conditions to Complete the First Merger” beginning on page 144.

In the event that the merger agreement is terminated and BANC receives all or any portion of the termination fee, BANC may be required to pay (i) the Warburg Investors an amount equal to 16.3% and (ii) the Centerbridge Investor an amount equal to 3.7%, in each case, of the amount of the termination fee net of certain out-of-pocket fees, costs and expenses of BANC. See the section entitled “The Investment Agreement—Commitment Compensation and Transaction Expenses” beginning on page 161 for a more detailed discussion of the circumstances under which BANC is required to pay the Investors a percentage of the termination fee.

In addition, if the merger agreement is terminated, the investment agreements will automatically terminate and BANC will not issue the shares of BANC common stock, shares of BANC NVCE stock or warrants pursuant to the investment agreements. Also, the amendment and restatement of the BANC existing omnibus stock incentive plan, to be renamed the Amended and Restated Banc of California, Inc. 2018 Omnibus Stock Incentive Plan, and the BANC charter amendment will not become effective.

Record Holders. For shares held directly, please complete, sign, date and return each proxy card (or cast your vote by telephone or internet as provided on each proxy card) or otherwise follow the voting instructions provided in this joint proxy statement/prospectus in order to ensure that all of your shares of BANC common stock or PACW common stock are voted.

Beneficial Owners. For shares held in “street name” through a bank, broker, trustee or other nominee, you should follow the procedures provided by your bank, broker, trustee or other nominee in order to vote your shares.

PACW Stockholders: If you have any questions about the mergers or how to submit your proxy or voting instruction card, or if you need additional copies of this document or the enclosed proxy card or voting instruction card, you should contact PACW’s proxy solicitor, Okapi Partners LLC, by emailing info@okapipartners.com or by calling toll-free at 888-785-6709, or for banks, brokers, trustees and other nominees, collect at 212-297-0720.

Certain brokerage firms may have instituted householding for beneficial owners of BANC common stock and PACW common stock, as applicable, held through such brokerage firms. If your family has multiple accounts holding BANC common stock or PACW common stock, as applicable, you may have already received a householding notification from your broker. Please contact your broker directly if you have any questions or require additional copies of this joint proxy statement/prospectus. The broker will arrange for delivery of a separate copy of this joint proxy statement/prospectus promptly upon your written or oral request. You may decide at any time to revoke your decision to household, and thereby receive multiple copies.

Some of the statements contained in this joint proxy statement/prospectus, or in documents incorporated by reference or attached as annexes to this joint proxy statement/prospectus, are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Exchange Act. Any statement that does not describe historical or current facts is a forward-looking statement.

Forward-looking statements may be identified by the use of the words such as “estimate,” “plan,” “project,” “forecast,” “intend,” “expect,” “anticipate,” “believe,” “seek,” “strategy,” “future,” “opportunity,” “may,” “could,” “target,” “should,” “will,” “would,” “will be,” “will continue,” “will likely result,” or similar expressions that predict or indicate future events or trends or that are not statements of historical matters, although not all forward-looking statements contain such identifying words. Forward-looking statements are based on current expectations, estimates and projections about PACW’s and BANC’s businesses, beliefs of PACW’s and BANC’s managements and assumptions made by PACW’s and BANC’s managements. These statements are not guarantees of future performance and are subject to numerous risks, uncertainties and assumptions (“future factors”) which are difficult to predict, change over time, and are often beyond the control of BANC, PACW and the combined company. Therefore, actual outcomes and results may differ materially from what is expressed or forecasted in such forward-looking statements.

While there is no assurance that any list of future factors is complete, in addition to the factors relating to the mergers discussed under the section entitled “Risk Factors” and the risk factors previously discussed in BANC’s and PACW’s reports filed with the SEC, which could cause actual results to differ materially from those contained or implied in the forward-looking statements, below are certain future factors, among others:

For any forward-looking statements made in this joint proxy statement/prospectus or in any documents incorporated by reference into or attached as annexes to this joint proxy statement/prospectus, BANC and PACW claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act, and Section 21E of the Exchange Act. You are cautioned not to place undue reliance on the forward-looking statements, which speak only as of the date of this joint proxy statement/prospectus or the dates of the documents incorporated by reference in or attached as annexes to this joint proxy statement/prospectus. Annualized, pro forma, projected and estimated numbers are

used for illustrative purposes only, are not forecasts and may not reflect actual results. Except as required by applicable law, neither BANC nor PACW undertakes to update these forward-looking statements to reflect facts, circumstances, assumptions or events that occur after the date the forward-looking statements are made.

For additional information about factors that could cause actual results to differ materially from those described in the forward-looking statements, please see the reports that BANC and PACW have filed with the SEC as described under the section entitled “ Where You Can Find More Information ” beginning on page 216 .

BANC and PACW expressly qualify in their entirety all forward-looking statements attributable to either of them or any person acting on their behalf by the cautionary statements contained in, referred to, attached to or incorporated by reference into this joint proxy statement/prospectus.

An investment by PACW stockholders in BANC common stock as a result of the exchange of shares of PACW common stock for shares of BANC common stock in the first merger involves certain risks. Similarly, a decision on the part of BANC stockholders to approve the BANC issuance also involves risks for BANC stockholders, who will continue to hold their shares of BANC common stock after the mergers. Certain material risks and uncertainties connected with the merger agreement and the investment agreements and transactions contemplated thereby and ownership of BANC common stock are discussed below. In addition, BANC and PACW have discussed certain other material risks connected with the ownership of BANC common stock and with BANC’s business, and with the ownership of PACW common stock and PACW’s business, respectively, under the caption “Risk Factors” appearing in their Annual Reports on Form 10-K most recently filed with the SEC, and BANC may include additional or updated disclosures of such material risks in its subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K that BANC may file with the SEC after the date of this joint proxy statement/prospectus.

PACW stockholders and BANC stockholders should carefully read and consider all of these risks and all other information contained in this joint proxy statement/prospectus, including the discussions of risk factors included in the documents incorporated by reference into or attached hereto as annexes to this joint proxy statement/prospectus, in deciding whether to vote for approval of the various proposals for which they may be entitled to vote at the PACW special meeting or the BANC special meeting. The risks described in this joint proxy statement/prospectus and in those documents incorporated by reference herein or attached as annexes hereto may adversely affect the value of BANC common stock that you, as an existing BANC stockholder, currently hold or that you, as an existing PACW stockholder, will hold upon consummation of the first merger, and could result in a significant decline in the value of BANC common stock and cause BANC stockholders and/or PACW stockholders to lose all or part of the value of their respective investments in BANC common stock.

In the first merger, the PACW stockholders will be entitled to receive 0.6569 of a share of BANC common stock for each share of PACW common stock they own, subject to certain exceptions. Although the number of shares of BANC common stock that PACW stockholders will be entitled to receive per share of PACW common stock is fixed, the market value of the merger consideration will fluctuate with the market price of BANC common stock and will not be known at the time of the BANC and PACW special meetings. Neither BANC nor PACW is permitted to terminate the merger agreement as a result of any increase or decrease in the market price of BANC common stock or PACW common stock.

Stock price changes may result from a variety of factors, including general market and economic conditions, changes in BANC’s and PACW’s businesses, operations and prospects, the performance of peer companies and other financial companies, volatility in the prices of securities in global financial markets, including market prices of BANC common stock, PACW common stock and the other public traded banking institutions as well as changes in applicable laws and regulations, many of which are beyond BANC’s and PACW’s control. Therefore, at the time of the BANC special meeting and the PACW special meeting, BANC stockholders and PACW stockholders will not know the market value of the merger consideration that PACW stockholders will receive at the effective time. Furthermore, the implied value of BANC common stock to be paid to the PACW stockholders upon completion of the first merger could be at the closing of the mergers (and was at the time of announcement of the merger agreement) significantly less than $10.54, which was the closing price per share of PACW common stock on the last trading day before the public announcement of the merger agreement, based on any fluctuations in the market price of BANC common stock. You should obtain current market quotations for shares of BANC common stock (NYSE: BANC) and for shares of PACW common stock (NASDAQ: PACW).

As a result of the first merger, PACW stockholders will become BANC stockholders, and certain adjustments may be made to the combined company’s business as a result of the mergers. Accordingly, the results of operations of the combined company and the market price of BANC common stock and BANC depositary shares after the completion of the mergers may be affected by factors different from those currently affecting the independent results of operations of each of BANC and PACW. For a discussion of the businesses of BANC and PACW and of certain factors to consider in connection with those businesses, see the documents incorporated by reference in, or attached as annexes to, this joint proxy statement/prospectus.

The opinion of JPM, BANC’s financial advisor, to the BANC board of directors, was delivered on and dated July 25, 2023 and the opinion of PSC, PACW’s financial advisor, to the PACW board of directors was delivered on and dated July 25, 2023. Changes in the operations and prospects of BANC or PACW, general market and economic conditions and other factors which may be beyond the control of BANC and PACW, including the ongoing effects of the COVID-19 pandemic on such market and economic conditions, and the market prices of BANC common stock and PACW common stock, may have altered the value of BANC or PACW or the prices of shares of BANC common stock and PACW common stock as of the date of this joint proxy statement/prospectus, or may alter such values and prices by the effective time. The opinions do not speak as of the date of this joint proxy statement/prospectus or as of any other date subsequent to the dates of those opinions.

Before the mergers and the bank merger may be completed, the requisite approvals, consents and non-objections must be obtained from the Federal Reserve and the DFPI. Under the investment agreements, before the investments by the Investors may be completed, the Warburg Investors and the Centerbridge Investor each must have received reasonably satisfactory oral confirmation from staff of the legal division of the Federal Reserve that the consummation of the applicable investment will not result in such Investor being deemed to have, or to have acquired, “control” of BANC or any of its subsidiaries for purposes of the BHC Act or the CIBC Act and the related regulations, either individually or as part of an association or group “acting in concert”. Other approvals, waivers or consents from regulators may also be required, both for the mergers and for the investments.

In determining whether to grant these approvals and confirmations, such regulatory authorities consider a variety of factors. These approvals or confirmations could be delayed or not obtained at all, including due to (i) a party’s regulatory standing (or adverse development in respect thereof), (ii) any other factors considered by regulators when granting such approvals or confirmations, including governmental, political or community group inquiries, investigations or opposition, or (iii) changes in legislation or the political environment generally.

The approvals that are granted may impose terms and conditions, limitations, obligations or costs, or place restrictions on the conduct of the combined company’s business or require changes to the terms of the transactions contemplated by the merger agreement or the investment agreements. There can be no assurance that regulators will not impose any such conditions, limitations, obligations or restrictions and that such conditions, limitations, obligations or restrictions will not have the effect of delaying or jeopardizing the completion of any of the transactions contemplated by the merger agreement or the investment agreements, imposing additional material costs on or materially limiting the revenues of the combined company following the mergers or otherwise reducing the anticipated benefits of the mergers (including the investments and their inclusion as common equity tier 1 capital, assuming the mergers and the investments are consummated successfully and within the expected timeframe). In addition, there can be no assurance that any such conditions, limitations, obligations or restrictions will not result in abandonment of the mergers and the investments. Additionally, the completion of the mergers and the investments is conditioned on the absence of certain orders, injunctions or decrees by any governmental entity of competent jurisdiction that would prevent, prohibit or make illegal the completion of any of the transactions contemplated by the merger agreement or the investment agreements, as applicable.

BANC and PACW have agreed in the merger agreement to use reasonable best efforts to consummate the transactions contemplated by the merger agreement on the terms and conditions set forth therein, including using reasonable best efforts to satisfy all conditions and covenants under their control in the merger agreement. However, under the terms of the merger agreement, neither BANC nor PACW, nor any of their respective subsidiaries, is required or permitted (without the written consent of the other party), to take any action, or commit to take or refrain from taking any action, or agree to any condition or restriction, in connection with obtaining the required permits, authorizations, consents, orders or approvals of governmental entities that would (i) reasonably be expected to require the combined company or any other person to issue equity securities or otherwise raise capital in excess of the amount contemplated by the investments under the merger agreement; or (ii) (A) not apply to a similarly sized financial holding company and state member bank that are well-capitalized and well-managed and (B) be materially more burdensome, individually or in the aggregate, on the operations, business or profitability of the combined company and its subsidiaries than those imposed on BANC or BANC N.A. as of the date of the merger agreement (a “materially burdensome regulatory condition”).

BANC and the Investors have agreed in the investment agreements to use reasonable best efforts to promptly prepare and file for all permits, consents, approvals, confirmations and authorizations of all third parties and governmental entities that are necessary or advisable to consummate the investments as promptly as reasonably practicable, and to respond to any request for information from any government authority related to the foregoing, so as to enable the parties to consummate the transactions contemplated by the investment agreements. However, under the terms of the investment agreements, neither BANC nor any of its subsidiaries is permitted (without the written consent of the other party), and none of the Investors or any of their affiliates is required, to take any action, or commit to take or refrain from taking any action, or accept or agree to any condition or restriction, that would reasonably be expected to cause any Investor, any of their respective affiliates or any of their partners or principals to (A) “control” BANC or be required to become a bank holding company, in each case, pursuant to the BHC Act; (B) “control” BANC or be required to provide prior notice pursuant to the CIBC Act; (C) serve as a source of financial strength to BANC pursuant to the BHC Act; or (D) enter into any capital or liquidity maintenance agreement or any similar agreement with any governmental entity, provide capital support to BANC, PACW or any of their respective subsidiaries or otherwise commit to or contribute any additional capital to, provide other funds to, or make any other investment in, BANC, PACW or any of their respective subsidiaries.

As a condition to the consummation of the mergers, BANC must substantially concurrently therewith consummate the purchase and sale of BANC common stock and BANC NVCE stock for an aggregate investment amount that is greater than or equal to $400 million pursuant to (i) the investment agreements and/or (ii) any other contract or agreement entered into after the execution of the merger agreement providing for the issuance of shares of BANC common stock and/or BANC NVCE stock on equivalent terms and conditions as set forth in the investment agreements, in each case qualifying as common equity tier 1 capital (“qualifying equity securities”). As a condition to the consummation of each Investor’s investment, BANC must have substantially concurrently received an investment which, together with the Investor’s investment, constitutes an investment of $400 million or greater in BANC’s qualifying equity securities. Although BANC has legally binding agreements with each of the Warburg Investors and the Centerbridge Investor pursuant to which the Investors (in the aggregate) have agreed to invest $400 million in BANC’s qualifying equity securities substantially concurrently with the consummation of the mergers, the obligation of each Investor to make such investment is subject to various conditions. If any Investor fails to consummate its portion of the investments, BANC may be required to seek a new investment in BANC’s qualifying equity securities from other third parties, which may or may not be available (and may or may not be available on the same terms as the investment agreements). Failure to consummate (or a delay in consummating) the investments may cause the failure or delay in the ability of the parties to consummate the mergers.

The consummation of the mergers is subject to the receipt of requisite regulatory and stockholder approvals and the satisfaction of other closing conditions, including the substantially concurrent consummation of the investments, as noted above. If the mergers are not completed for any reason, including as a result of BANC

stockholders or PACW stockholders failing to grant the applicable requisite stockholder approval at the applicable company’s special stockholders meeting or the imposition of a materially burdensome regulatory condition resulting in either BANC or PACW refusing to consummate the mergers, there may be various adverse consequences and BANC and PACW may experience negative reactions from the financial markets and from their customers and employees. For example, BANC’s business and PACW’s business may each be impacted adversely by the failure to pursue other beneficial opportunities due to the focus of management on the mergers, without realizing any of the anticipated benefits of consummating the mergers.

Additionally, if the merger agreement is terminated, the market price of the BANC common stock and/or the PACW common stock could decline to the extent that current market prices reflect a market assumption that the mergers and/or, in the case of BANC, the investments will be beneficial and will be consummated. BANC or PACW also could be subject to litigation related to any failure to complete the mergers or, in the case of BANC, the investments or to proceedings commenced against BANC or PACW to perform its obligations under the merger agreement or, in the case of BANC, the investment agreements. If the merger agreement is terminated under certain circumstances, one party may be required to pay a termination fee of $39.5 million to the other party. If BANC receives a termination fee, it may be required to remit a portion of that fee to the Investors.

Additionally, BANC and PACW have incurred and will incur substantial expenses in connection with the negotiation and completion of the transactions contemplated by the merger agreement and, in the case of BANC, the investment agreements (including the investments and the balance sheet repositioning (as defined below)), as well as the costs and expenses of preparing, filing, printing and mailing of a joint proxy statement/prospectus in connection with the mergers, and all filing and other fees paid in connection with the mergers. As of the date of signing the merger agreement, such transaction and integration costs were estimated to be approximately $280 million pre-tax and approximately $215 million post-tax, but the actual costs could fluctuate. If the mergers and/or the investments are not completed, BANC and PACW would have to pay these expenses without realizing the expected benefits of the mergers and/or the investments, as applicable. Although BANC or PACW may be entitled to receive a termination fee of $39.5 million from the other party and/or expense reimbursement with respect to certain costs and expenses associated with the balance sheet repositioning if the merger agreement is terminated under certain circumstances, (i) such payments may not be sufficient to fully compensate BANC or PACW for the losses it may incur in connection with a failure of the mergers to be consummated and (ii) BANC may be required to remit a portion of the termination fee it receives to the Investors.

The success of the mergers will depend, in part, on the ability of BANC and PACW to dispose certain assets in the planned balance sheet repositioning (the “balance sheet repositioning”) along with anticipated cost savings from combining the businesses of BANC and PACW. To realize certain anticipated benefits and cost savings from the mergers, BANC and PACW must successfully dispose of assets at closing, which is inherently subject to market conditions and the risk that such conditions will be less favorable than what the parties expected when entering into the merger agreement, and successfully integrate and combine their businesses in a manner that permits those benefits and cost savings to be realized without adversely affecting current revenues and future growth. If BANC and PACW are not able to successfully achieve these objectives, such anticipated benefits and cost savings of the mergers may not be realized fully or at all or may take longer to realize than expected. In addition, the actual cost savings of the mergers could be less than anticipated, and integration may result in additional and unforeseen expenses. For reference, as of the date of signing the merger agreement, the costs savings for the transaction were estimated to be approximately $130 million or approximately 15% pre-tax expense reduction of the combined company’s run-rate expense base.

An inability to realize the full extent of the anticipated benefits of, the mergers and the other transactions contemplated by the merger agreement (including the balance sheet repositioning), as well as any delays encountered in the integration process, could have an adverse effect upon the capital position, revenues, levels of expenses and operating results of the combined company following the completion of the mergers, which may adversely affect the value of the common stock of the combined company following the completion of the mergers.

It is possible that the integration process could result in the loss of key employees, the disruption of each company’s ongoing businesses or inconsistencies in standards, controls, procedures and policies that adversely affect the companies’ ability to maintain relationships with their stakeholders or to achieve the anticipated benefits and cost savings of the mergers. Integration efforts between the companies may also divert management attention and resources. These integration matters could have an adverse effect on BANC or PACW during this pre-closing period and for an undetermined period after consummation of the mergers on the combined company.

Furthermore, the board of directors and executive leadership of the combined company and the surviving bank will consist of former directors and executive officers from each of BANC and PACW, as well as a director designated by the Warburg Investors. Combining the boards of directors and management teams of each company into a single board of directors and a single management team could require the reconciliation of differing priorities and philosophies.

The success of the mergers will depend, in part, on the combined company’s ability to retain the talent and dedication of key employees currently employed by BANC and PACW. It is possible that these employees may decide not to remain with BANC or PACW, as applicable, while the mergers are pending or with the combined company after the mergers are consummated. If BANC and PACW are unable to retain key employees, including management, who are critical to the successful integration and future operations of the companies, BANC and PACW could face disruptions in their operations, loss of existing customers, loss of key information, expertise or know-how and unanticipated additional recruitment costs. In addition, following the mergers, if key employees terminate their employment, the combined company’s business activities may be adversely affected, and management’s attention may be diverted from successfully hiring suitable replacements, all of which may cause the combined company’s business to suffer. BANC and PACW also may not be able to locate or retain suitable replacements for any key employees who leave either company.

Uncertainty about the effect of the mergers on employees and customers may have an adverse effect on BANC or PACW. These uncertainties may impair BANC’s or PACW’s ability to retain and motivate key personnel until the mergers are completed and could cause customers and others that deal with BANC or PACW to seek to change existing business relationships with BANC or PACW. In addition, subject to certain exceptions, each of BANC and PACW has agreed to operate its business in the ordinary course in all material respects and to refrain from taking certain actions that may adversely affect its ability to (i) consummate the transactions contemplated by the merger agreement on a timely basis without the consent of the other party and (ii) in the case of BANC, obtain any necessary approvals of any governmental entity in connection with the investments without the consent of the Investors. These restrictions may prevent BANC or PACW from pursuing attractive business opportunities that may arise prior to the completion of the mergers.

BANC and PACW have incurred and expect to incur a number of non-recurring costs associated with the mergers and, in the case of BANC, the investments. These costs include legal, financial, accounting, consulting and other advisory fees, retention, severance and employee benefit-related costs, public company filing fees and other regulatory fees, financial printing and other printing costs, closing, integration and other related costs. Some of these costs are payable by BANC and/or PACW regardless of whether the mergers are completed.

In addition, the combined company will incur integration costs following the completion of the mergers as BANC and PACW integrate their businesses, including facilities and systems consolidation costs and employment-related costs. BANC and PACW may also incur additional costs to maintain employee morale and to retain key employees. There are a large number of processes, policies, procedures, operations, technologies and systems that may need to be integrated, including purchasing, accounting and finance, payroll, compliance, treasury management, branch operations, vendor management, risk management, lines of business, pricing and

benefits. While BANC and PACW have assumed that a certain level of costs will be incurred, there are many factors beyond their control that could affect the total amount or the timing of the integration costs. Moreover, many of the costs that will be incurred are, by their nature, difficult to estimate accurately. These integration costs may result in the combined company taking charges against earnings following the completion of the mergers, and the amount and timing of such charges are uncertain at present. There can be no assurances that the expected benefits and efficiencies related to the integration of the businesses will be realized to offset these transaction and integration costs over time.

Stockholders may bring claims in connection with the mergers and/or the investments and, among other remedies, may seek damages or an injunction preventing the mergers and/or the investments from closing. In September 2023, PACW received four demands from purported stockholders challenging the transaction and generally alleging that certain disclosures in the preliminary joint proxy statement/prospectus filed on August 28, 2023 were false, misleading, contained incomplete statements or omitted material information, and asserting claims against PACW and the PACW board of directors for violations of Sections 14(a) and/or 20(a) of the Exchange Act. If any plaintiff were successful in obtaining an injunction prohibiting BANC or PACW from completing the mergers or any other transactions contemplated by the merger agreement or BANC and the Investors from consummating the investments (or any portion thereof), then such injunction may delay or prevent the effectiveness of the mergers and the investments and could result in costs to BANC or PACW, including costs in connection with the defense or settlement of any stockholder lawsuits filed in connection with the mergers and/or the investments. Further, such lawsuits and the defense or settlement of any such lawsuits may have an adverse effect on the financial condition and results of operations of BANC, PACW or the combined company.

The obligation of the merger agreement parties to consummate the first merger is subject to a number of conditions that must be satisfied or waived in order to consummate the mergers. Those conditions include, among other things: (i) receiving the requisite approval by each of the BANC stockholders and the PACW stockholders of certain matters relating to the mergers at each company’s respective special stockholders meeting; (ii) the receipt of the requisite regulatory approvals from the Federal Reserve and the DFPI and that no requisite regulatory approval contains any materially burdensome regulatory condition; (iii) the absence of any order, injunction, decree or other legal restraint preventing the consummation of the mergers, the bank merger or any of the other transactions contemplated by the merger agreement or making the completion of the merger, the bank merger or any of the other transactions contemplated by the merger agreement illegal; (iv) the registration statement of which this joint proxy statement/prospectus is a part being declared effective by the SEC under the Securities Act; and (v) the consummation of a total of $400 million or greater investment in BANC’s qualifying equity securities substantially concurrently with the closing of the mergers. Each party’s obligation to consummate the mergers is also subject to certain additional conditions, including: (a) subject to applicable materiality standards, the accuracy of the representations and warranties of the other party (including the absence of any material adverse effect, as defined in the merger agreement); (b) the performance in all material respects by the other party of its obligations under the merger agreement; and (c) the receipt by each party of an opinion from its counsel to the effect that the mergers will qualify as a reorganization within the meaning of Section 368(a) of the Code.

These conditions to the consummation of the first merger may not be satisfied or waived in a timely manner or at all, and, accordingly, the mergers may not be consummated. In addition, the parties can mutually decide to terminate the merger agreement at any time, before or after the requisite stockholder approvals, or PACW or BANC may elect to terminate the merger agreement in certain other circumstances, including by BANC upon the occurrence of a material adverse effect under certain circumstances with respect to PACW or by PACW upon the occurrence of a material adverse effect under certain circumstances with respect to BANC.

The obligation of the parties to each investment agreement to consummate the investments is subject to a number of conditions which must be satisfied or waived in order to consummate the investments. Those conditions include, among other things: (i) the substantially concurrent consummation of the mergers and the satisfaction of the conditions to the mergers under the merger agreement; (ii) the Warburg Investors and the Centerbridge Investor each must have received reasonably satisfactory oral confirmation from staff of the legal division of the Federal Reserve that the consummation of the applicable investments will not result in such Investor being deemed to have, or to have acquired, “control” of BANC or any of its subsidiaries for purposes of the BHC Act or CIBC Act; (iii) the absence of any order, injunction, decree or other legal restraint preventing the completion of the investments or making the completion of the investments or any of the other transactions contemplated by the investment agreements illegal; and (iv) the consummation, or substantially concurrent consummation, of a total of $400 million or greater investment in BANC’s qualifying equity securities. Each party’s obligation to consummate the investments is also subject to certain additional customary conditions, including (a) subject to applicable materiality standards, the accuracy of the representations and warranties of the other party, and (b) the performance in all material respects by the other party of its obligations under the applicable investment agreement.

These conditions to the consummation of the investments may not be satisfied or waived in a timely manner or at all, and, accordingly, the investments may not be consummated. In addition, the parties to each investment agreement can mutually decide to terminate the applicable investment agreement at any time, before or after the requisite stockholder approvals, or the parties may elect to terminate the applicable investment agreement in certain other circumstances.

Although neither BANC’s nor PACW’s balance sheet repositioning is a condition to consummate the first merger under the merger agreement, the regulators may not approve the mergers or the bank merger until the balance sheet repositioning can be completed to minimize capital and liquidity risk of the combined company. Therefore, if either BANC or PACW is unable to complete its balance sheet repositioning to the extent of any actions required to be undertaken prior to the merger closing, regulatory approval may be delayed or denied.

Under the merger agreement, BANC and PACW commit to use reasonable best efforts to enter into agreements to complete the balance sheet repositioning at the best commercially reasonable available price. Therefore, depending on the existence of various potential buyers and competitive prices, BANC or PACW may sell its assets at a significant loss, which could affect the financial condition and results of operations of BANC, PACW or the combined company.

Both BANC and PACW are expected to incur taxable losses in connection with the balance sheet repositioning. To the extent these taxable losses exceed BANC’s or PACW’s taxable income, as applicable, unused losses will carry forward to offset a portion of future taxable income, if any, until such unused losses expire, if at all.

Under Sections 382 and 383 of Code, these federal net operating loss carryforwards, certain losses incurred following the mergers, and other tax attributes may become subject to an annual limitation in the event of certain cumulative changes in BANC’s or PACW’s ownership. An “ownership change” pursuant to Section 382 of the Code generally occurs if one or more stockholders or groups of stockholders who own at least 5% of a company’s stock increase their ownership by more than 50 percentage points over their lowest ownership percentage within a rolling three-year period. Each of BANC’s and PACW’s ability to utilize net operating loss carryforwards, certain losses incurred following the mergers, and other tax attributes to offset future taxable income or tax liabilities may be limited as a result of ownership changes, including potential changes in connection with the mergers or other transactions. Similar rules may apply under state tax laws. Neither BANC nor PACW has determined the amount of the cumulative change in BANC’s or PACW’s ownership resulting from the mergers or other transactions, or any resulting limitations on BANC’s or PACW’s ability to utilize BANC’s or PACW’s net operating loss carryforwards, certain losses incurred following the mergers, and other

tax attributes. Such limitations could result in increased future income tax liability to BANC or PACW and BANC’s or PACW’s future cash flows could be adversely affected. The effect of such limitations could also adversely affect BANC’s and PACW’s regulatory capital ratios.

In certain circumstances, to preserve BANC’s or PACW’s ability to utilize BANC’s or PACW’s tax attributes without limitation, BANC, PACW or the combined company may take actions to attempt to prevent an “ownership change” from occurring, including by adopting provisions that would limit or discourage stockholders from acquiring 5% or more of BANC or PACW or in the case of stockholders that already own 5% or more of BANC or PACW, from increasing their ownership. There can be no assurances that such actions will be available, or if such actions are available, whether BANC, PACW or the combined company will decide to undertake any such actions and if such actions are undertaken, whether such actions would be effective in preventing an “ownership change” pursuant to Section 382 of the Code.

The unaudited pro forma condensed combined financial information in this joint proxy statement/prospectus is presented for illustrative purposes only and is not necessarily indicative of what the combined company’s actual financial condition or results of operations would have been had the mergers and the investments been completed on the dates indicated. The unaudited pro forma condensed combined financial information reflects adjustments, which are based upon preliminary estimates, to record BANC’s identifiable assets acquired and liabilities assumed at fair value and the resulting goodwill recognized. The merger consideration value allocation reflected in this joint proxy statement/prospectus is preliminary, and the final allocation thereof will be based upon the value of the actual merger consideration and the fair value of the assets and liabilities of BANC as of the closing date. Accordingly, the actual value of the merger consideration may vary significantly from the value used in preparing the unaudited pro forma combined consolidated financial information in this joint proxy statement/prospectus. Accordingly, the final acquisition accounting adjustments may differ materially from the pro forma adjustments reflected in this document.

BANC stockholders and PACW stockholders should be aware that some of BANC’s and PACW’s directors and executive officers may have interests in the mergers and have arrangements that are different from, or in addition to, those of BANC stockholders and PACW stockholders. These interests and arrangements may create potential conflicts of interest. The BANC board of directors and the PACW board of directors were aware of these respective interests and considered these interests, among other matters, when making their decisions to approve the merger agreement, and in recommending that BANC stockholders vote to approve the BANC issuance proposal, the BANC incentive plan proposal, the BANC exemption amendment proposal and the BANC adjournment proposal and that PACW stockholders vote to approve the PACW merger proposal, the PACW compensation proposal and the PACW adjournment proposal.

Upon the closing of the subsequent merger, BANC will assume PACW’s outstanding indebtedness, which is estimated to be approximately $7.2 billion based on the amount outstanding as of June 30, 2023. BANC’s existing debt (including PACW’s assumed indebtedness), together with any future incurrence of additional indebtedness, could have important consequences for the combined company’s creditors and stockholders. For example, it could:

Whether or not the mergers are ultimately consummated, as a result of uncertainty related to the proposed transactions, risks relating to the impact of the announcement of the mergers on BANC’s and PACW’s business include the following:

If any of the aforementioned risks were to materialize, they could lead to significant costs which may impact each party’s results of operations and financial condition.

The merger agreement contains customary “no shop” covenants that restrict each of BANC’s and PACW’s ability to, directly or indirectly, among other things, initiate, solicit, knowingly encourage or knowingly facilitate inquiries or proposals with respect to, or, subject to certain exceptions generally related to the exercise of fiduciary duties by each respective board of directors, engage or participate in any negotiations concerning, or provide any confidential or nonpublic information or data relating to, any alternative acquisition proposals, subject to certain exceptions. These provisions, which could result in a $39.5 million termination fee payable under certain circumstances, may discourage a potential third-party acquirer that might have an interest in acquiring all or a significant part of BANC or PACW from considering or making that acquisition proposal.

Upon completion of the first merger, the rights of former PACW stockholders who receive shares of BANC common stock in the first merger and thereby become BANC stockholders will be governed by the BANC charter and the BANC bylaws. The rights associated with PACW common stock are different from the rights associated with BANC common stock. In addition, the rights of stockholders under Maryland law, where BANC is incorporated, may differ from the rights of stockholders under Delaware law, where PACW is incorporated. See the section entitled “Comparison of the Rights of BANC stockholders and PACW stockholders.”

BANC stockholders and PACW stockholders currently have the right to vote in the election of the board of directors and on other matters affecting BANC and PACW, respectively. Each BANC stockholder and each PACW stockholder before the mergers will be a BANC stockholder upon completion of the mergers, with a percentage ownership of the shares of common stock of the combined company that is smaller than the holder’s percentage ownership of either shares of BANC common stock or shares of PACW common stock individually,

as applicable, prior to the consummation of the mergers. Further, based on the number of shares of BANC common stock and PACW common stock outstanding as of the close of business on the respective record dates, and based on the number of shares of BANC common stock expected to be issued in the first merger and the investments, the former PACW stockholders, as a group, are estimated to receive approximately 47% of the outstanding shares of the combined company immediately after the first merger and the investments, and the shares of BANC common stock currently held by BANC stockholders as a group are estimated to represent approximately 34% of the outstanding shares of the combined company immediately after the first merger and the investments. As such, a former stockholder of PACW will, immediately after the merger closing, own a percentage of BANC common stock equal to such stockholder’s current percentage ownership of PACW multipled by approximately 47% (disregarding any ownership of BANC such stockholder may otherwise hold). Because of this, PACW stockholders may have less influence on the management and policies of the combined company than they now have on the management and policies of PACW, and BANC stockholders may have less influence on the management and policies of the combined company after the closing of the mergers than they now have on the management and policies of BANC.

In connection with the payment of the merger consideration, BANC expects to issue approximately 77.9 million shares of BANC common stock to PACW stockholders and approximately 1 million shares of BANC common stock to the holders of PACW restricted stock awards. The issuance of these new shares of BANC common stock may result in fluctuations in the market price of BANC common stock, including a stock price decrease.

You should read and consider risk factors specific to BANC’s business that will also affect the combined company after the mergers. These risks are described in the “Risk Factors” section of BANC’s Annual Report on Form 10-K for the year ended December 31, 2022, and in any updates to those risk factors set forth in BANC’s Quarterly Reports on Form 10-Q and in other documents incorporated by reference into this joint proxy statement/prospectus. Please see the section entitled “Where You Can Find More Information” beginning on page 216 of this joint proxy statement/prospectus for the location of information incorporated by reference into this joint proxy statement/prospectus.

You should read and consider risk factors specific to PACW’s business that will also affect the combined company after the mergers. These risks are described in the “Risk Factors” section of PACW’s Annual Report on Form 10-K for the year ended December 31, 2022, and in any updates to those risk factors set forth in PACW’s Quarterly Reports on Form 10-Q and in other documents attached as annexes to this joint proxy statement/prospectus. Please see the section entitled “Where You Can Find More Information” beginning on page 216 of this joint proxy statement/prospectus for the location of information that is attached as annexes to this joint proxy statement/prospectus.

This section contains information for BANC stockholders about the special meeting that BANC has called to allow BANC stockholders to consider and vote on the BANC issuance proposal, the BANC incentive plan proposal, the BANC exemption amendment proposal and the BANC adjournment proposal. This joint proxy statement/prospectus is accompanied by a notice of the BANC special meeting, and a form of proxy card that the BANC board of directors is soliciting for use by BANC stockholders at the BANC special meeting and at any adjournments or postponements of the BANC special meeting.

The BANC special meeting will be held on [  ], 2023 at [  ], Pacific Time at 3 MacArthur Place, Santa Ana, CA 92707, or at any postponement or adjournment thereof.

At the BANC special meeting, BANC stockholders will be asked to consider and vote on the following proposals:

The BANC board of directors unanimously recommends that the BANC stockholders vote “FOR” the BANC issuance proposal, “FOR” the BANC incentive plan proposal, “FOR” the BANC exemption amendment proposal and “FOR” the BANC adjournment proposal. See the section entitled “The Transactions—BANC’s Reasons for the Mergers; Recommendation of the BANC Board of Directors” for a more detailed discussion of the BANC board of directors’ recommendation.

The BANC board of directors has fixed the close of business on [  ], 2023 as the BANC record date for the determination of BANC stockholders entitled to notice of, and to vote at, the BANC special meeting. As of the close of business on the BANC record date, there were [  ] shares of BANC common stock outstanding held by [  ] holders of record.

The presence at the BANC special meeting, in person or by proxy, of holders entitled to cast one-third of all the votes entitled to be cast at the meeting will constitute a quorum for the transaction of business at the BANC special meeting. Abstentions will be included in determining the number of shares present at the meeting for the purpose of determining the presence of a quorum. As it is expected that all proposals to be voted on at the BANC special meeting will be “non-routine” matters, as discussed in the section entitled “—Broker Non-Votes,” BANC does not expect any broker non-votes to occur at the BANC special meeting.

Under the BANC bylaws, even if less than a quorum, the chair of the meeting or the holders of a majority of the shares of BANC common stock entitled to vote who are present, in person or by proxy, may adjourn the meeting from time to time without further notice.

At the BANC special meeting, each share of BANC common stock is entitled to one vote on all matters properly submitted to BANC stockholders; provided, however, that under Section F of Article 6 of the BANC charter, no BANC stockholder who beneficially owns more than ten percent (10%) of BANC common stock outstanding as of the BANC record date may vote shares held in excess of that amount.

Each of the members of the BANC board of directors has entered into a voting agreement with PACW in which such director has agreed to vote all BANC common stock that such director owns and has the power to vote in favor of the BANC issuance proposal and any other matter that is reasonably necessary to be approved by the BANC stockholders to facilitate the consummation of the transactions contemplated by the merger agreement.

Such persons also agreed to vote against any proposal made in opposition to the approval of the adoption of the merger agreement or that is otherwise in competition or inconsistent with the transactions contemplated by the merger agreement, against any acquisition proposal and against any proposal, transaction, agreement or amendment to BANC’s organizational documents or other action that is intended to or could reasonably be expected to prevent, impede, interfere with, materially delay, postpone, adversely affect or discourage the consummation of the first merger. As of the close of business on the BANC record date, such persons beneficially owned and were entitled to vote, in the aggregate, [  ] shares of BANC common stock, allowing them to exercise approximately [ ]% of the voting power of BANC common stock (which does not include shares issuable upon the exercise, vesting or settlement of BANC equity-based awards that were not outstanding as of the close of business on the BANC record date).

A broker non-vote occurs when (a) a bank, broker, trustee or other nominee has discretionary authority to vote on one or more proposals to be voted on at a meeting of stockholders but is not permitted to vote on other proposals without instructions from the beneficial owner of the shares and (b) the beneficial owner fails to provide the bank, broker, trustee or other nominee with such instructions. Under stock exchange rules, banks, brokers, trustees and other nominees holding shares in “street name” do not have discretionary voting authority with respect to any of the proposals described in this joint proxy statement/prospectus to be voted at the BANC special meeting. It is expected that all proposals to be voted on the BANC special meeting will be “non-routine” matters, and, as such, if a beneficial owner of shares of BANC common stock held in “street name” does not give voting instructions to the bank, broker, trustee or other nominee, then those shares will not be counted as present in person or by proxy at the BANC special meeting and will not be counted for purposes of establishing a quorum.

Broker non-votes only count toward a quorum if at least one proposal is presented with respect to which the bank, broker, trustee or other nominee has discretionary authority. Since it is expected that all proposals to be voted on at the BANC special meeting will be “non-routine” matters, BANC does not expect any broker non-votes to occur at the BANC special meeting.

Assuming a quorum is present, if you hold shares of BANC common stock in “street name” and fail to issue voting instructions to your bank, broker, trustee or other nominee, it will not have any effect on the BANC issuance proposal, the BANC incentive plan proposal or the BANC adjournment proposal, but will have the effect of a vote “AGAINST” the BANC exemption amendment proposal.

Vote required: Approval of the BANC issuance proposal requires the affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting. Approval of the BANC issuance proposal is a condition to the completion of the first merger and the investments.

Effect of abstentions and failure to vote: An abstention by a BANC stockholder who is present (in person or by proxy) at the BANC special meeting (or a BANC stockholder who is not present at the BANC special meeting and does not respond by proxy) will have no effect on the BANC issuance proposal. If you are a beneficial owner of BANC common stock and you do not instruct your bank, broker, trustee or other nominee on how to vote your shares of BANC common stock, your bank, broker, trustee or other nominee will not be able to vote your shares on the BANC issuance proposal or any other proposal being considered by the BANC stockholders as described in this joint proxy statement/prospectus and therefore such shares of BANC common stock will not be counted for purposes of establishing a quorum. Assuming a quorum is present, the failure to vote on the BANC issuance proposal will not have any effect on the BANC issuance proposal.

Vote required: Approval of the BANC incentive plan proposal requires the affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting. Approval of the BANC incentive plan proposal is not a condition to the completion of the mergers or the investments. In addition, if the mergers are not consummated, then the amendment and restatement of the BANC existing omnibus stock incentive plan will not occur.

Effect of abstentions and failure to vote: An abstention by a BANC stockholder who is present (in person or by proxy) at the BANC special meeting (or a BANC stockholder who is not present at the BANC special meeting and does not respond by proxy) will have no effect on the BANC incentive plan proposal. If you are a beneficial owner of BANC common stock and you do not instruct your bank, broker, trustee or other nominee on how to vote your shares of BANC common stock, your bank, broker, trustee or other nominee may not vote your shares on the BANC incentive plan proposal and therefore such shares of BANC common stock will not be counted for purposes of establishing a quorum. Assuming a quorum is present, the failure to vote on the BANC incentive plan proposal will not have any effect on the BANC incentive plan proposal.

Vote required: Approval of the BANC exemption amendment proposal requires the affirmative vote of the holders of a majority of the outstanding shares of BANC common stock entitled to vote on the proposal. Approval of the BANC exemption amendment proposal is not a condition to the completion of the mergers or the investments. In addition, if the mergers are not consummated, then the BANC charter exemption amendment will not become effective.

Effect of abstentions and failure to vote: An abstention by a BANC stockholder who is present (in person or by proxy) at the BANC special meeting (or a BANC stockholder who is not present at the BANC special meeting and does not respond by proxy) will have the same effect as a vote “AGAINST” the BANC exemption amendment proposal. If you are a beneficial owner of BANC common stock and you do not instruct your bank, broker, trustee or other nominee on how to vote your shares of BANC common stock, your bank, broker, trustee or other nominee may not vote your shares on the BANC exemption amendment proposal and therefore such shares of BANC common stock will not be counted for purposes of establishing a quorum. The failure to vote on the BANC exemption amendment proposal will have the same effect as a vote “AGAINST” the BANC exemption amendment proposal.

Vote required: Whether or not a quorum will be present at the meeting, approval of the BANC adjournment proposal requires the affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting. Approval of the BANC adjournment proposal is not a condition to the completion of the mergers or the investments.

Effect of abstentions and failure to vote: An abstention by a BANC stockholder who is present (in person or by proxy) at the BANC special meeting (or a BANC stockholder who is not present at the BANC special meeting and does not respond by proxy) will have no effect on the BANC adjournment proposal. If you are a beneficial owner of BANC common stock and you do not instruct your bank, broker, trustee or other nominee on how to vote your shares of BANC common stock, your bank, broker, trustee or other nominee may not vote your shares on the BANC adjournment proposal and therefore such shares of BANC common stock will not be counted for purposes of establishing a quorum. Assuming a quorum is present, the failure to vote on the BANC adjournment proposal will not have any effect on the BANC adjournment proposal.

If you are a holder of record of BANC common stock on the BANC record date, you will be able to attend the BANC special meeting, ask questions and vote during the meeting. Each person attending the BANC special meeting must present a valid, government issued form of identification in order to be admitted to the BANC special meeting. Each stockholder attending also must provide proof of ownership of shares of BANC common stock as of the BANC record date. If you are a record holder, proof of ownership will be established by BANC’s verification of your name against BANC’s list of record holders as of the BANC record date.

If you hold your shares of BANC common stock through a bank, broker, trustee or other nominee and you would like to attend and vote in person at the BANC special meeting, you will need to obtain a legal proxy from the holder of record of your BANC common stock indicating that you were the beneficial owner of those shares on the BANC record date and that you are authorized to vote such shares. Please contact your bank, broker, trustee or other nominee for further instructions. Additionally, you must provide one of the following as proof of ownership: (a) account statement showing share ownership as of the BANC record date, (b) a copy of an email that you received with instructions containing a link to the website where the BANC’s proxy materials are

available and a valid control number, (c) a valid legal proxy containing a valid control number or a letter from a record holder naming you as proxy, or (d) a letter from the bank, broker, trustee or other nominee through which you hold your shares confirming your ownership as of the BANC record date. See the section entitled “—Shares Held in Street Name” below for further information. If you hold your shares through a bank, broker, trustee or other nominee and you do not want to attend the BANC special meeting, please contact the respective entity for instructions on how to vote your shares of BANC common stock at the BANC special meeting.

Even if you plan to attend the BANC special meeting, BANC recommends that you vote your shares in advance by proxy as described below so that your vote will be counted if you later decide not to or become unable to attend the BANC special meeting.

A BANC stockholder may vote by proxy or at the BANC special meeting. If you hold your shares of BANC common stock in your name as a record holder, to submit a proxy, you, as a BANC stockholder, may use one of the following methods:

If you intend to submit your proxy by telephone or via the internet, you must do so by [  ], Pacific Time, on the day before the BANC special meeting. If you intend to submit your proxy by mail, your completed proxy card must be received prior to the BANC special meeting.

BANC requests that BANC stockholders vote by telephone, over the internet or by completing, signing, dating and returning the accompanying proxy card and returning it to BANC as soon as possible in the enclosed postage-paid envelope. When the accompanying proxy card is returned properly executed, the shares of BANC common stock represented by it will be voted at the BANC special meeting in accordance with the instructions contained on the proxy card. If you make no specification on your proxy card as to how you want your shares voted before signing and returning it, your proxy will be voted “FOR” the BANC issuance proposal, “FOR” the BANC incentive plan proposal, “FOR” the BANC exemption amendment proposal and “FOR” the BANC adjournment proposal.

If you hold your shares through a bank, broker, trustee or other nominee, you should check the voting instruction card provided by your bank, broker, trustee or other nominee to determine whether you may vote by telephone or the internet.

Every vote is important. Accordingly, you should sign, date and return the enclosed proxy card, or vote via the internet or by telephone, whether or not you plan to attend the BANC special meeting. Sending in your proxy card or voting by telephone or on the internet will not prevent you from voting your shares personally at the BANC special meeting because you may revoke your proxy at any time before it is voted. See “—Revocability of Proxies” below for further information.

If you hold shares in the name of a bank, broker, trustee or other nominee (e.g., in a brokerage or other account in “street name”), then you are a “beneficial owner” of such shares. Please follow the instructions on the voting instruction card furnished by such bank, broker, trustee or other nominee in order to vote such shares.

If your shares are held in the name of a bank, broker, trustee or other nominee, you must instruct the bank, broker, trustee or other nominee on how to vote your shares. You may not vote shares held in “street name” by returning a proxy card directly to BANC unless you have obtained a legal proxy from your bank, broker, trustee or other nominee.

Further, banks, brokers, trustees or other nominees who hold shares of BANC common stock on behalf of their customers may not give a proxy to BANC to vote those shares with respect to any of the proposals without

specific instructions from their customers, as brokers, banks, trustees and other nominees do not have discretionary voting power on the proposals that will be voted upon at the BANC special meeting, including the BANC issuance proposal, BANC incentive plan proposal, BANC exemption amendment proposal and BANC adjournment proposal.

If you directly hold shares of BANC common stock in your name as a record holder, you can change your vote at any time before your proxy is voted at your meeting. You can do this by:

If you are a beneficial owner and your shares are held by a bank, broker, trustee or other nominee, you may change your vote by:

Attendance at the BANC special meeting will not in and of itself constitute revocation of a proxy. A revocation or later-dated proxy received by BANC after the vote will not affect the vote. If you intend to submit your proxy by telephone or via the internet, you must do so by [ ], Pacific Time, on the day before the BANC special meeting. If you intend to submit your proxy by mail, your completed proxy card must be received prior to the BANC special meeting.

Although it is not currently expected, the BANC special meeting may be adjourned or postponed for the purpose of soliciting additional proxies. In the event that there is present, in person or by proxy, sufficient favorable voting power to secure the vote of BANC stockholders necessary to approve the BANC issuance proposal, BANC does not anticipate that it will adjourn or postpone the BANC special meeting, unless it is advised by counsel that such adjournment or postponement is necessary under applicable law to allow additional time for any disclosure. Any adjournment or postponement of the BANC special meeting for the purpose of soliciting additional proxies will allow BANC stockholders who have already sent in their proxies to revoke them at any time prior to their use at the BANC special meeting as adjourned or postponed.

As permitted by applicable law, only one copy of this joint proxy statement/prospectus is being delivered to BANC stockholders residing at the same address, unless such BANC stockholders have notified BANC of their desire to receive multiple copies of the joint proxy statement/prospectus.

BANC will promptly deliver, upon oral or written request, a separate copy of the joint proxy statement/prospectus to any BANC stockholder residing at an address to which only one copy of such document was mailed. Requests for additional copies should be directed to BANC’s proxy solicitor, Okapi Partners LLC, by emailing info@okapipartners.com or by calling toll-free at 888-785-6673, or for banks, brokers, trustees and other nominees, collect at 212-297-0720.

BANC and PACW will share equally the expenses incurred in connection with the printing and mailing of this joint proxy statement/prospectus. To assist in the solicitation of proxies, BANC has retained Okapi Partners LLC to assist it in soliciting proxies and has agreed to pay Okapi Partners LLC a fee of $[ ] plus the reimbursement

of certain costs and expenses incurred in connection with the solicitation. BANC and its proxy solicitor may also request banks, brokers, trustees and other nominees holding shares of BANC common stock beneficially owned by others to send this document to, and obtain proxies from, the beneficial owners and may reimburse such record holders for their reasonable out-of-pocket expenses in so doing. Solicitation of proxies by mail may be supplemented by telephone and other electronic means, advertisements and personal solicitation by the directors, officers or employees of BANC. No additional compensation will be paid to our directors, officers or employees for solicitation.

BANC management knows of no other business to be presented at the BANC special meeting, but if any other matters are properly presented at the meeting or any adjournments or postponements thereof, the persons named in the proxies will vote upon them in accordance with the recommendation of the BANC board of directors.

If you need assistance in completing your proxy card, have questions regarding the BANC special meeting or would like additional copies of this joint proxy statement/prospectus, please contact Investor Relations, Banc of California, 3 MacArthur Place, Santa Ana, CA 92707, email IR@bancofcal.com or telephone: (855) 361-2262 or BANC’s proxy solicitor, Okapi Partners LLC, by emailing info@okapipartners.com or by calling toll-free at 888-785-6673, or for banks, brokers, trustees and other nominees, collect at 212-297-0720.

BANC is asking the BANC stockholders to approve the issuance of BANC common stock to PACW stockholders pursuant to the merger agreement and the issuance of BANC common stock, BANC NVCE stock and warrants to the Investors pursuant to the investment agreements.

Pursuant to the merger agreement, BANC expects to issue approximately 77.9 million shares of BANC common stock and approximately 1 million shares of BANC common stock to the holders of PACW restricted stock awards in connection with the consummation of the first merger. Pursuant to the investment agreements, BANC will issue (a) approximately (i) 21.8 million shares of BANC common stock and (ii) 10.8 million shares of BANC NVCE stock and (b) warrants to purchase approximately (i) 15.9 million shares of BANC NVCE stock and (ii) 3.0 million shares of BANC common stock, in each case, in connection with the consummation of the investments.

Under the NYSE Listed Company Manual, a company listed on the NYSE is required to obtain stockholder approval prior to the issuance of common stock, or of securities convertible into or exercisable for common stock, in any transaction or series of related transactions if (a) the common stock has, or will have upon issuance, voting power equal to or in excess of 20% of the voting power outstanding before the issuance of such stock or securities convertible into or exercisable for common stock, or (b) the number of shares of common stock to be issued is, or will be upon issuance, equal to or in excess of 20% of the number of shares of common stock outstanding before the issuance of the common stock or of securities convertible into or exercisable for common stock.

If the first merger and the investments are completed, the number of shares of BANC common stock issued, and securities convertible into or exercisable for BANC common stock, will exceed 20% of the BANC common stock outstanding before such issuance. In this proposal, BANC is asking BANC stockholders to authorize the issuance of BANC common stock, BANC NVCE stock and warrants in connection with the first merger and the investments.

Approval of the BANC issuance proposal requires the affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting. The approval of the BANC issuance proposal is a condition to the completion of the first merger and the investments.

The BANC board of directors unanimously recommends a vote “FOR” the BANC issuance proposal.

On August 25, 2023, on the recommendation of its Joint Compensation, Nominating and Corporate Governance Committee, the BANC board of directors has determined that it is necessary and appropriate to amend and restate BANC’s existing 2018 omnibus stock incentive plan, to be renamed the Amended and Restated Banc of California, Inc., 2018 Omnibus Stock Incentive Plan, or the “A&R 2018 Plan”, pursuant to which the combined company will be able to make grants of equity-based awards to employees, officers, directors and consultants of the combined company following the closing of the transactions contemplated by the merger agreement. The combined company will have a substantially larger number of employees who are eligible to receive equity-based awards, and the BANC board of directors believes that the A&R 2018 Plan is needed to ensure that the combined company has a sufficient number of shares available to make these grants following the closing of the transactions contemplated by the merger agreement. The existing BANC 2018 Omnibus Stock Incentive Plan (the “Current Plan”) was adopted more than five years ago and the remaining share reserve is unlikely to be sufficient to make these grants. As described in more detail below, the terms of the A&R 2018 Plan are substantially similar to the terms contained in the Current Plan, except that the A&R 2018 Plan:

If approved by BANC stockholders at the BANC special meeting, contingent upon the closing of the transactions contemplated by the merger agreement, the A&R 2018 Plan will replace the Current Plan and the Amended and Restated PacWest 2017 Stock Incentive Plan with respect to any future equity-based awards effective as of the closing of the transactions contemplated by the merger agreement. In the event the BANC stockholders do not approve the A&R 2018 Plan at the BANC special meeting, the A&R 2018 Plan will not become effective. Upon the closing of the transactions contemplated by the merger agreement, awards that are then outstanding under the Current Plan and the Amended and Restated PacWest 2017 Stock Incentive Plan will continue to remain outstanding under those plans as adjusted for the effects of the transaction. For more information on the treatment of these awards in connection with the transactions, please see the section entitled “The Merger Agreement—Treatment of PACW Equity Awards” and the section entitled “The Merger Agreement—Treatment of BANC Equity Awards”.

The terms and conditions of the A&R 2018 Plan are substantially similar to those that are currently included in the Current Plan, except as noted above, which BANC has determined are still appropriate from a corporate governance and general market standard perspective. An overview of the key corporate governance provisions is provided below.

✔ Provide for a minimum one-year vesting period subject to a 5% carve-out.

✔ Provide for “double-trigger vesting” of awards, so that a change in control does not, by itself, trigger full vesting of an award.

✔ Provide for an annual limit on director awards.

✔ Provide for administration by the Joint Compensation, Nominating and Corporate Governance Committee of the board of directors of the combined company, which committee will consist entirely of independent directors, or such other committee or subcommittee as may be appointed by the board of directors of the combined company.

✘ Contain any “evergreen” provision that automatically adds additional shares to the plan pool.

✘ Permit direct or indirect repricing of underwater options or stock appreciation rights without stockholder approval.

✘ Permit the grant of options with below-market exercise prices other than in connection with substitute awards.

✘ Permit re-issuance, or recycling, of shares tendered or withheld to pay the exercise price of an option or shares used to satisfy withholding obligations with respect to outstanding awards.

✘ Permit BANC to pay and deliver dividends or dividend equivalents on any awards prior to vesting or permit BANC to pay dividends or dividend equivalents on stock options or stock appreciation rights.

The total number of shares of BANC common stock that will be available for issuance under the A&R 2018 Plan effective as of the closing of the transactions contemplated by the merger agreement will be equal to [  ], plus a number of shares that are reserved for awards under the Current Plan but are unissued as of the effective date of the A&R 2018 Plan, subject in each case to equitable adjustment in the event of certain corporate transactions or similar events. In addition, shares underlying awards that are outstanding under the Current Plan that become forfeited, terminated, expired, lapsed or settled for cash will become available for issuance pursuant to awards issued under the A&R 2018 Plan. As of August 15, 2023, a total of 1,901,322 shares of BANC common stock were available for issuance pursuant to new awards under the Current Plan, and 1,343,303 shares were available for issuance pursuant to outstanding awards under the Current Plan, assuming BANC PSU Awards were achieved at target performance. In reaching the conclusion as to the appropriateness of the number of shares of BANC common stock requested to be reserved for equity-based awards under the A&R 2018 Plan, the BANC board of directors reviewed key metrics that are typically used to evaluate such recommendations, including burn rate and dilution. Since the A&R 2018 Plan will be used for grants of equity-based awards to employees and other applicable service providers of the combined company following the closing of the transactions contemplated by the merger agreement, the BANC board of directors reviewed these key metrics both for BANC and PACW to ensure that it had the most comprehensive set of information in making its determinations.

The table below illustrates BANC’s historical grant practices.

The information included in this joint proxy statement/prospectus and BANC’s 2022 Annual Report on Form 10-K is updated by the following information regarding all existing BANC equity compensation plans as of June 30, 2023 (except as noted otherwise):

Overhang provides a measure of potential dilution. The total number of shares of BANC common stock subject to outstanding awards, plus the total number of shares of BANC common stock available for future grants under the Current Plan, represents a current overhang percentage of 1.9%, calculated on a fully-diluted basis using the post-transaction shares of BANC common stock outstanding. If the BANC stockholders approve the A&R 2018 Plan, the issuance of an additional [ ] shares of BANC common stock would increase BANC’s overhang by [ ], calculated using the same methodology, which would result in total potential dilution of [ ].

This section summarizes the material terms of the A&R 2018 Plan and is qualified in its entirety by the full text of the A&R 2018 Plan, which is included as Annex J to this joint proxy statement/prospectus. Capitalized terms used below and not defined in this proposal are as defined in the A&R 2018 Plan.

The following is a summary of certain U.S. federal income tax consequences of awards made under the A&R 2018 Plan based upon the laws in effect on the date hereof. The discussion is general in nature and does not take into account a number of considerations that may apply in light of the circumstances of a particular participant under the A&R 2018 Plan. The income tax consequences under applicable state and local tax laws may not be the same as under U.S. federal income tax laws.

Non-Qualified Stock Options. A participant will not recognize taxable income at the time of grant of a non-qualified stock option, and BANC will not be entitled to a tax deduction at such time. A participant will recognize compensation taxable as ordinary income (and subject to income tax withholding in respect of an employee) upon exercise of a non-qualified stock option equal to the excess of the fair market value of the shares purchased at the time of exercise over their exercise price. BANC will be entitled to a deduction in the amount of ordinary income recognized by the participant, subject to the deduction limitations of Section 162(m) of the Code.

Incentive Stock Options. A participant will not recognize taxable income at the time of grant of an incentive stock option. A participant will not recognize taxable income (except for purposes of the alternative minimum tax) upon exercise of an incentive stock option. If the shares acquired by exercise of an incentive stock option are held for the longer of two years from the date the option was granted and one year from the date of exercise, any gain or loss arising from a subsequent disposition of such shares will be taxed as long-term capital gain or loss, and BANC will not be entitled to any deduction. If, however, such shares are disposed of within such two- or one-year periods, then in the year of such disposition the participant will recognize compensation taxable as ordinary income equal to the excess of the lesser of the amount realized upon such disposition and the fair market value of such shares on the date of exercise over the exercise price. BANC will be entitled to a deduction in the amount of any ordinary income recognized by the participant, subject to the deduction limitations of Section 162(m) of the Code. The excess of the amount realized through the disposition date over the fair market value of the stock on the exercise date will be treated as capital gain.

Stock Appreciation Rights. A participant will not recognize taxable income at the time of grant of a stock appreciation right, and BANC will not be entitled to a tax deduction at such time. Upon exercise, a participant will recognize compensation taxable as ordinary income (and subject to income tax withholding in respect of an employee) equal to the fair market value of any shares delivered and the amount of cash paid by us. BANC will be entitled to a deduction in the amount of ordinary income recognized by the participant, subject to the deduction limitations of Section 162(m) of the Code.

Restricted Stock. A participant will not recognize taxable income at the time of grant of shares of restricted stock, and BANC will not be entitled to a tax deduction at such time, unless the participant makes an election under Section 83(b) of the Code to be taxed at such time. If such election is made, the participant will recognize compensation taxable as ordinary income (and subject to income tax withholding in respect of an employee) at the time of the grant equal to the excess of the fair market value of the shares at such time over the amount, if any, paid for such shares. If such election is not made, the participant will recognize compensation taxable as ordinary income (and subject to income tax withholding in respect of an employee) at the time the restrictions lapse in an amount equal to the excess of the fair market value of the shares at such time over the amount, if any, paid for such shares. BANC will be entitled to a deduction in the amount of ordinary income recognized by the participant, subject to the deduction limitations of Section 162(m) of the Code.

Restricted Stock Units. A participant will not recognize taxable income at the time of grant of a restricted stock unit, and BANC will not be entitled to a tax deduction at such time. A participant will recognize compensation taxable as ordinary income (and subject to income tax withholding in respect of an employee) at the time of settlement of the award equal to the fair market value of any shares delivered and the amount of cash paid by us. BANC will be entitled to a deduction in the amount of ordinary income recognized by the participant, subject to the deduction limitations of Section 162(m) of the Code.

Performance Units. A participant will not recognize taxable income at the time of grant of performance units, and BANC will not be entitled to a tax deduction at such time. A participant will recognize compensation taxable as ordinary income (and subject to income tax withholding in respect of an employee) at the time of settlement of the award equal to the fair market value of any shares or property delivered and the amount of cash paid by us. BANC will be entitled to a deduction in the amount of ordinary income recognized by the participant, subject to the deduction limitations of Section 162(m) of the Code.

The foregoing general tax discussion is intended for the information of BANC stockholders considering how to vote with respect to this proposal and not as tax guidance to participants in the A&R 2018 Plan. Participants are strongly urged to consult their own tax advisors regarding the federal, state, local, foreign and other tax consequences to them of participating in the A&R 2018 Plan.

The benefits that will be awarded or paid under the A&R 2018 Plan are not currently determinable. Awards granted under the A&R 2018 Plan will be within the discretion of the Joint Compensation, Nominating and Corporate Governance Committee of board of directors of the combined company, and no determinations have been made about future awards or who might receive them.

The following table sets forth information as of December 31, 2022 with respect to compensation plans under which shares of BANC common stock may be issued:

If approved by stockholders at the BANC special meeting, the A&R 2018 Plan will become effective as of the closing of the transactions contemplated by the merger agreement. By approving the A&R 2018 Plan, the BANC stockholders will also satisfy the NYSE requirements for stockholder approval of equity compensation plans.

As noted above, if BANC stockholders do not approve the A&R 2018 Plan at the BANC special meeting, the A&R 2018 Plan will not become effective.

The affirmative vote of a majority of the votes cast on the proposal is required to approve this proposal.

The BANC board of directors unanimously recommends a vote “FOR” the BANC incentive plan proposal.

BANC is asking the BANC stockholders to approve the amendment of Section F of Article 6 of the BANC charter in a manner to exempt the Warburg Investors and their affiliates (but not any other stockholder of BANC) from the application of Section F of Article 6 (other than paragraph 4 thereof, which deals mainly with the quorum requirement for meetings of BANC stockholders) of the BANC charter. Under Section F of Article 6 of the BANC charter, no person who beneficially owns, directly or indirectly, more than 10% of the then-outstanding shares of BANC common stock is entitled to vote any shares held in excess of the 10% threshold. A copy of the proposed BANC charter amendment is attached to this joint proxy statement/prospectus as Annex D. BANC stockholders should read the BANC charter amendment in its entirety.

Pursuant to the Warburg investment agreement, BANC has agreed to, among other things, use reasonable best efforts to submit to the BANC stockholders the proposed BANC charter amendment for the requisite approval of the BANC stockholders at the BANC special meeting. A copy of the Warburg investment agreement is attached to this joint proxy statement/prospectus as Annex B. BANC stockholders should read the Warburg investment agreement in its entirety.

Approval of the BANC exemption amendment proposal requires the affirmative vote of the holders of a majority of the outstanding shares of BANC common stock entitled to vote on the proposal. The approval of the BANC exemption amendment proposal by BANC stockholders is not a condition to the completion of the mergers or the investments. If approved by stockholders at the BANC special meeting, contingent upon the closing of the transactions contemplated by the merger agreement, the BANC charter will be amended by the BANC charter amendment, which form is attached to this joint proxy statement/prospectus as Annex D.

Under the Warburg investment agreement, if the BANC exemption amendment proposal is not approved by BANC stockholders at the BANC special meeting, but the Warburg investment is nevertheless consummated, BANC will be required to, at each annual meeting of the BANC stockholders following the Warburg investment closing until such time as the BANC exemption amendment proposal is duly approved, use reasonable best efforts (including recommending the BANC exemption amendment proposal to the BANC stockholders) to (i) submit to the BANC stockholders the BANC exemption amendment proposal and (ii) obtain the requisite approval of the BANC stockholders of the BANC exemption amendment proposal at any such meeting of the BANC stockholders; provided that following the first anniversary of the Warburg investment closing, BANC’s foregoing obligations described in this paragraph will be subject to receipt of a written request from the Warburg Investors no later than 30 business days prior to the anniversary of the date on which BANC first filed its proxy materials for the preceding annual BANC stockholder meeting.

Following the receipt of the requisite approval of the BANC stockholders of the BANC exemption amendment proposal, BANC will be required under the Warburg investment agreement to file the BANC exemption amendment with the Maryland Department of State. This filing will be made in connection with the Warburg investment closing if the BANC exemption amendment proposal is approved at the BANC special meeting.

The BANC board of directors unanimously recommends a vote “FOR” the BANC exemption amendment proposal.

The BANC special meeting may be adjourned to another time or place, if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the BANC special meeting to approve the BANC issuance proposal. If, at the BANC special meeting, the number of shares of BANC common stock present or represented and voting in favor of the BANC issuance proposal is insufficient to approve the BANC issuance proposal, BANC intends to move to adjourn the BANC special meeting in order to enable the BANC board of directors to solicit additional proxies for approval of the BANC issuance proposal. In that event, BANC will ask BANC stockholders to vote upon the BANC adjournment proposal, but not the BANC issuance proposal.

In this proposal, BANC is asking BANC stockholders to authorize the holder of any proxy solicited by the BANC board of directors, on a discretionary basis, to vote in favor of adjourning the BANC special meeting to another time and place for the purpose of soliciting additional proxies, including the solicitation of proxies from BANC stockholders who have previously voted, if a quorum is not present or if there are not sufficient votes at the time of the BANC special meeting to approve the BANC issuance proposal. Pursuant to the BANC bylaws, the BANC special meeting may be adjourned without further notice being given.

Whether or not a quorum will be present at the meeting, approval of the BANC adjournment proposal requires the affirmative vote of a majority of votes cast by holders of shares of BANC common stock at the BANC special meeting.

The approval of the BANC adjournment proposal by BANC stockholders is not a condition to the completion of the mergers or the investments.

The BANC board of directors unanimously recommends a vote “FOR” the BANC adjournment proposal.

This section contains information for PACW stockholders about the special meeting of PACW stockholders that PACW has called to allow PACW stockholders to consider and vote on the PACW merger proposal, the PACW compensation proposal and the PACW adjournment proposal. This joint proxy statement/prospectus is accompanied by a notice of the PACW special meeting, and a form of proxy card that the PACW board of directors is soliciting for use by PACW stockholders at the PACW special meeting and at any adjournments or postponements of the PACW special meeting.

The PACW special meeting will be held on [ ], 2023, at [ ], Mountain Time, at Denver Marriott Tech Center, 4900 S. Syracuse St, Denver, CO 80237, or at any postponement or adjournment thereof.

At the PACW special meeting, PACW stockholders will be asked to consider and vote on the following matters:

The PACW board of directors has determined that the mergers are fair to, advisable and in the best interests of PACW and PACW stockholders and has unanimously approved the merger agreement. The PACW board of directors unanimously recommends that PACW stockholders vote “FOR” the PACW merger proposal, “FOR” the PACW compensation proposal and “FOR” the PACW adjournment proposal. See the section entitled “The Transactions—PACW’s Reasons for the Mergers; Recommendation of the PACW Board of Directors” for a more detailed discussion of the PACW board of directors’ recommendation.

The PACW board of directors has fixed the close of business on [ ], 2023 as the PACW record date for the determination of PACW stockholders entitled to notice of, and to vote at, the PACW special meeting. As of the close of business on the PACW record date, there were [ ] shares of PACW common stock outstanding held by [ ] holders of record. Each holder of record of PACW common stock is entitled to cast one vote on each matter properly brought before the PACW special meeting for each share of PACW common stock that such holder owned of record as of the PACW record date.

Holders of a majority of the shares of PACW common stock entitled to vote on a matter at the PACW special meeting, present in person or represented by proxy, will constitute a quorum for the transaction of business at the PACW special meeting. All shares of PACW common stock present in person or represented by proxy, including abstentions, will be treated as present for purposes of determining the presence or absence of a quorum for all matters voted on at the PACW special meeting. Because, under applicable rules, banks, brokers, trustees and other nominees do not have discretionary voting authority with respect to any of the three proposals described in this joint proxy statement/prospectus to be voted on by PACW stockholders, if a beneficial owner of PACW common stock held in “street name” does not give voting instructions to the record holder of its, his or her shares, then those shares will not be counted as present in person or by proxy at the PACW special meeting if no other proposals are brought before the PACW special meeting.

Each of the directors of PACW has entered into a voting agreement with BANC in which such director has agreed to vote all PACW common stock that such director owns and has the power to vote in favor of the PACW merger proposal and any other matter that is reasonably necessary to be approved by the PACW stockholders to facilitate the consummation of the transactions contemplated by the merger agreement. Such persons also agreed to vote against any proposal made in opposition to the approval of the adoption of the merger agreement or that is otherwise in competition or inconsistent with the transactions contemplated by the merger agreement, against any acquisition proposal and against any proposal, transaction, agreement or amendment to PACW’s organizational documents or other action that is intended to or could reasonably be

expected to prevent, impede, interfere with, materially delay, postpone, adversely affect or discourage the consummation of the first merger. As of the close of business on the PACW record date, such persons beneficially owned and were entitled to vote, in the aggregate, [ ] shares of PACW common stock, allowing them to exercise approximately [ ]% of the voting power of PACW common stock (which does not include shares issuable upon the exercise, vesting or settlement of PACW equity-based awards that were not outstanding as of the close of business on the PACW record date).

A broker non-vote occurs when (a) a bank, broker, trustee or other nominee has discretionary authority to vote on one or more proposals to be voted on at a meeting of stockholders but is not permitted to vote on other proposals without instructions from the beneficial owner of the shares and (b) the beneficial owner fails to provide the bank, broker, trustee or other nominee with such instructions. Under stock exchange rules, banks, brokers, trustees and other nominees holding shares in “street name” do not have discretionary voting authority with respect to any of the proposals described in this joint proxy statement/prospectus to be voted at the PACW special meeting. It is expected that all proposals to be voted on the PACW special meeting will be “non-routine” matters, and, as such, if a beneficial owner of shares of PACW common stock held in “street name” does not give voting instructions to the bank, broker, trustee or other nominee, then those shares will not be counted as present in person or by proxy at the PACW special meeting and will not be counted for purposes of establishing a quorum.

Broker non-votes only count toward a quorum if at least one proposal is presented with respect to which the bank, broker, trustee or other nominee has discretionary authority. Since it is expected that all proposals to be voted on at the PACW special meeting will be “non-routine” matters, PACW does not expect any broker non-votes to occur at the PACW special meeting.

As the vote to approve the PACW merger proposal is based on the total number of shares of PACW common stock outstanding at the close of business on the record date, if you are a PACW stockholder and fail to issue voting instructions to your bank, broker, trustee or other nominee, it will have the same effect as a vote “AGAINST” the PACW merger proposal. Assuming a quorum is present, the failure to vote will not have any effect on the PACW compensation proposal or the PACW adjournment proposal. Although PACW does not expect to bring any matters before the PACW special meeting other than the three PACW proposals described in this joint proxy statement/prospectus, if an additional matter is brought before the PACW special meeting and is one on which brokers have discretionary voting authority and you fail to provide instructions to your broker with respect to the PACW compensation proposal or the PACW adjournment proposal, such broker non-votes will be counted for purposes of determining a quorum and have the same effect as a vote “AGAINST” such proposal.

Vote required: Approval of the PACW merger proposal requires the affirmative vote of the holders of a majority of the outstanding shares of PACW common stock entitled to vote on the merger agreement. Approval of the PACW merger proposal is a condition to the completion of the first merger and the investments.

Effect of abstentions and failure to vote: If you fail to vote, mark “ABSTAIN” on your proxy or fail to instruct your bank or broker with respect to the PACW merger proposal, it will have the same effect as a vote “AGAINST” the proposal.

Vote required: Approval of the PACW compensation proposal requires the affirmative vote of the holders of at least a majority of the shares of PACW common stock present or represented by proxy at the PACW special meeting. Approval of the PACW compensation proposal is not a condition to the completion of the first merger or the investments.

Effect of abstentions and failure to vote: If you mark “ABSTAIN” on your proxy card, it will have the same effect as a vote “AGAINST” the proposal. If you fail to submit a proxy card or vote in person at the PACW special meeting, or fail to instruct your bank or broker with respect to the PACW compensation proposal, it will have no effect on the proposal.

Vote required: Whether or not a quorum is present, approval of the PACW adjournment proposal requires the affirmative vote of the holders of at least a majority of the shares of PACW common stock present or represented by proxy at the PACW special meeting. Approval of the PACW adjournment proposal is not a condition to the completion of the first merger or the investments.

Effect of abstentions and failure to vote: If you mark “ABSTAIN” on your proxy card, it will have the same effect as a vote “AGAINST” the proposal. If you fail to submit a proxy card or vote in person at the PACW special meeting, or fail to instruct your bank or broker how to vote with respect to the PACW adjournment proposal, it will have no effect on the proposal.

All PACW stockholders, including stockholders of record of PACW common stock and PACW stockholders who hold their shares through banks, brokers, trustees or other nominees, are invited to attend the PACW special meeting. PACW stockholders of record can vote in person at the PACW special meeting. If you are not a PACW stockholder of record, you must obtain a legal proxy executed in your favor from the record holder of your shares to be able to vote in person at the PACW special meeting. If you plan to attend the PACW special meeting, you must hold your shares in your own name or have a letter from the record holder of your shares confirming your ownership. In addition, you must bring a form of personal photo identification with you in order to be admitted to the meeting. PACW reserves the right to refuse admittance to anyone without proper proof of share ownership or without proper photo identification.

If you are a stockholder of record of PACW common stock, you may have your shares of PACW common stock voted on matters presented at the PACW special meeting in any of the following ways:

If you are a beneficial owner of shares of PACW common stock held in “street name,” you should receive instructions from your bank, broker, trustee or other nominee of record that you must follow in order to have your shares of PACW common stock voted. Those instructions will identify which of the above choices are available to you in order to have your shares of PACW common stock voted. If you have not received such voting instructions or require further information regarding such voting instructions, contact your broker. If your bank, broker, trustee or other nominee holds your shares of PACW common stock in “street name,” such record holder will vote your shares of PACW common stock only if you provide instructions on how to vote by filling out the voter instruction form sent to you by such record holder with this joint proxy statement/prospectus. Please note that, if you are a beneficial owner of shares of PACW common stock held in “street name” and wish to vote in person at the PACW special meeting, you must provide a legal proxy executed in your favor from your bank, broker or other holder of record at the PACW special meeting.

If you submit a proxy, regardless of the method you choose to submit such proxy, the individuals named on the enclosed proxy card, and each of them, with full power of substitution, will vote your shares of PACW common stock in the way that you indicate. When completing the Internet or telephone processes or the proxy card, you

may specify whether your shares of PACW common stock should be voted for or against, or may choose to abstain from voting, on all, some or none of the specific items of business to come before the PACW special meeting.

All shares represented by valid proxies that PACW receives through this solicitation, and that are not revoked, will be voted in accordance with your instructions on the proxy card. If you properly sign your proxy card but do not mark the boxes showing how your shares of PACW common stock should be voted on a matter, the shares of PACW common stock represented by your properly signed proxy will be voted in accordance with the recommendation of the PACW board of directors, which, as of the date of this joint proxy statement/prospectus, are “FOR” the PACW merger proposal, “FOR” the PACW compensation proposal and “FOR” the PACW adjournment proposal.

Please refer to the instructions on your proxy or voting instruction card to determine the deadlines for submitting your proxy over the Internet or by telephone. If you choose to submit a proxy by mailing a proxy card, your proxy card should be mailed in the accompanying prepaid reply envelope and must be received by PACW’s Corporate Secretary by the time the PACW special meeting begins.

If you are the stockholder of record of your shares of PACW common stock, you have the right to revoke a proxy, whether delivered over the Internet, by telephone or by mail, at any time before it is exercised, by submitting a later-dated proxy through any of the methods available to you, by giving written notice of revocation to PACW’s Corporate Secretary, which must be received by the Corporate Secretary by 5:00 p.m. Mountain Time on the business day immediately prior to the date of the PACW special meeting, or by attending the PACW special meeting and voting in person. Attending the PACW special meeting alone, without voting at the PACW special meeting, will not be sufficient to revoke your proxy. Written notice of revocation should be mailed to: 9701 Wilshire Blvd., Suite 700, Beverly Hills, CA 90212.

If you are a “street name” holder of PACW common stock, you may change your vote by submitting new voting instructions to your bank, broker or other holder of record. You must contact the record holder of your shares to obtain instructions as to how to change your proxy vote.

Although it is not currently expected, the PACW special meeting may be adjourned or postponed for the purpose of soliciting additional proxies. In the event that there is present, in person or by proxy, sufficient favorable voting power to secure the vote of PACW stockholders necessary to approve the PACW merger proposal, PACW does not anticipate that it will adjourn or postpone the PACW special meeting, unless it is advised by counsel that such adjournment or postponement is necessary under applicable law to allow additional time for any disclosure. Any adjournment or postponement of the PACW special meeting for the purpose of soliciting additional proxies will allow PACW stockholders who have already sent in their proxies to revoke them at any time prior to their use at the PACW special meeting as adjourned or postponed.

As permitted by the Exchange Act, only one copy of this joint proxy statement/prospectus is being delivered to multiple PACW stockholders sharing an address, unless PACW has previously received contrary instructions from one or more such stockholders. This is referred to as “householding.” Stockholders who hold their shares in “street name” can request further information on householding through their banks, brokers or other holders of record. On written or oral request to PACW’s proxy solicitor, Okapi Partners LLC, by emailing info@okapipartners.com or by calling toll-free at 888-785-6709, or for banks, brokers, trustees and other nominees, collect at 212-297-0720, PACW will deliver promptly a separate copy of this document to a stockholder at a shared address to which a single copy of the document was delivered.

PACW is soliciting the proxies of PACW stockholders in conjunction with the mergers. PACW will bear the cost of soliciting proxies from PACW stockholders. In addition to solicitation of proxies by mail, PACW will request that banks, brokers, trustees and other nominees send proxies and proxy material to the beneficial owners of

PACW common stock and secure their voting instructions. PACW has also made arrangements with Okapi Partners LLC to assist it in soliciting proxies and has agreed to pay Okapi Partners LLC a fee of $25,000 plus the reimbursement of certain costs and expenses incurred in connection with the solicitation.

PACW management knows of no other business to be presented at the PACW special meeting, but if any other matters are properly presented at the meeting or any adjournments or postponements thereof, the persons named in the proxies will vote upon them in accordance with the recommendation of the PACW board of directors.

If you are a PACW stockholder and have questions about the mergers or how to submit your proxy, or if you need additional copies of this joint proxy statement/prospectus, the enclosed proxy card or voting instructions, please contact PacWest Bancorp, Investor Relations, 9701 Wilshire Blvd., Suite 700, Beverly Hills, CA 90212, or Okapi Partners LLC, by emailing info@okapipartners.com or by calling toll-free at 888-785-6709, or for banks, brokers, trustees and other nominees, collect at 212-297-0720.

Pursuant to the merger agreement, PACW is asking PACW stockholders to adopt the merger agreement. PACW stockholders should read this joint proxy statement/prospectus carefully and in its entirety, including the annexes, for more detailed information concerning the merger agreement and the mergers. A copy of the merger agreement is attached to this joint proxy statement/prospectus as Annex A. After careful consideration, the PACW board of directors, by a unanimous vote, (i) determined that the merger agreement and the transactions contemplated thereby are fair to, advisable and in the best interests of PACW and PACW stockholders and (ii) adopted and approved the merger agreement and the transactions contemplated thereby.

The approval of the PACW merger proposal by PACW stockholders is a condition to the completion of the first merger and the investments.

The PACW board of directors unanimously recommends a vote “FOR” the PACW merger proposal.

Pursuant to Section 14A of the Exchange Act and Rule 14a-21(c) thereunder, PACW is seeking a non-binding, advisory stockholder approval of the compensation of PACW’s named executive officers that is based on or otherwise relates to the mergers as disclosed in the section entitled “The Transactions—Interests of Certain PACW Directors and Executive Officers in the Mergers—Quantification of Potential Payments and Benefits to PACW’s Named Executive Officers” beginning on page 117. The proposal gives PACW stockholders the opportunity to vote, on a non-binding, advisory basis, on the merger-related compensation that may be paid or become payable to PACW’s named executive officers.

The PACW board of directors encourages you to review carefully the named executive officer merger-related compensation information disclosed in this joint proxy statement/prospectus, and, accordingly, is asking PACW stockholders to vote “FOR” the adoption of the following resolution, on a non-binding advisory basis:

“RESOLVED, that the compensation that will or may be paid or become payable to the PACW named executive officers, in connection with the mergers, and the agreements or understandings pursuant to which such compensation will or may be paid or become payable, in each case as disclosed pursuant to Item 402(t) of Regulation S-K in “The Transactions—Interests of Certain PACW Directors and Executive Officers in the Mergers—Quantification of Potential Payments and Benefits to PACW’s Named Executive Officers” is hereby APPROVED.”

The vote on the PACW compensation proposal is a vote separate and apart from the votes on the PACW merger proposal and the PACW adjournment proposal. Accordingly, if you are a PACW stockholder, you may vote to approve the PACW merger proposal and/or the PACW adjournment proposal and vote not to approve the PACW compensation proposal, and vice versa. The approval of the PACW compensation proposal by PACW stockholders is not a condition to the completion of the first merger and the investments. Because the vote on the PACW compensation proposal is advisory only, it will not affect the obligation of PACW or BANC to pay or provide the compensation contemplated by the compensation agreements and arrangements. Accordingly, if the mergers are completed, the merger-related compensation will be paid to PACW’s named executive officers to the extent payable in accordance with the terms of the compensation agreements and arrangements even if PACW stockholders fail to approve the advisory vote regarding merger-related compensation.

The PACW board of directors unanimously recommends a vote “FOR” the PACW compensation proposal.

The PACW special meeting may be adjourned to another time or place, if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the PACW special meeting to approve the PACW merger proposal. If, at the PACW special meeting, the number of shares of PACW common stock present or represented and voting in favor of the PACW merger proposal is insufficient to approve the PACW merger proposal, PACW intends to move to adjourn the PACW special meeting in order to enable the PACW board of directors to solicit additional proxies for approval of the PACW merger proposal. In that event, PACW will ask PACW stockholders to vote upon the PACW adjournment proposal, but not the PACW merger proposal.

In this proposal, PACW is asking PACW stockholders to authorize the holder of any proxy solicited by the PACW board of directors, on a discretionary basis, to vote in favor of adjourning the PACW special meeting to another time and place for the purpose of soliciting additional proxies, including the solicitation of proxies from PACW stockholders who have previously voted, if a quorum is not present or if there are not sufficient votes at the time of the PACW special meeting to approve the PACW merger proposal. Pursuant to the PACW bylaws, the PACW special meeting may be adjourned without further notice being given if the new time and place is announced at the meeting prior to adjournment and the date is set 30 days or less from the date of the original PACW special meeting.

The approval of the PACW adjournment proposal by PACW stockholders is not a condition to the completion of the first merger and the investments.

The PACW board of directors unanimously recommends a vote “FOR” the PACW adjournment proposal.

3 MacArthur Place

Santa Ana, California 92707-7704

(855) 361-2262

BANC, a Maryland corporation, was incorporated in March 2002 and serves as the holding company for its wholly-owned subsidiary, BANC N.A., a California-based bank. BANC has 32 offices, including 26 full-service branches located throughout Southern California. BANC has served California markets since 1941 through BANC N.A. and its predecessors. As of June 30, 2023, BANC, together with its subsidiaries, had total assets of $9.37 billion, loans and leases, net of deferred fees, of $7.08 billion, total deposits of $6.87 billion and total stockholders’ equity of $0.957 billion.

Through its dedicated professionals, BANC provides customized and innovative banking and lending solutions to businesses, entrepreneurs and individuals throughout California, and full stack payment processing solutions through its subsidiary Deepstack Technologies. BANC helps to improve the communities where it lives and works, by supporting organizations that provide financial literacy and job training, small business support and affordable housing. With a commitment to service and to building enduring relationships, BANC provides a higher standard of banking.

BANC’s principal source of income is dividends from BANC N.A. BANC N.A., a national banking association regulated by the OCC, is a relationship-focused, full-service business banking organization. It offers an array of commercial loan and deposit products and services, including demand, savings and money market accounts, certificates of deposit, commercial and industrial loans, commercial real estate and multifamily loans, Small Business Administration loans and construction loans, and other business-oriented products.

Shares of BANC common stock are traded on the NYSE under the trading symbol “BANC.”

For more information about BANC, please visit BANC’s website at www.bancofcal.com. The information provided on BANC’s website (other than the documents incorporated by reference herein) is not part of this joint proxy statement/prospectus and is not incorporated herein by reference. Additional information about BANC is included in documents incorporated by reference in this joint proxy statement/prospectus. See the section entitled “Where You Can Find More Information” on page 216.

3 MacArthur Place

Santa Ana, California 92707-7704

(855) 361-2262

Merger Sub is a Delaware corporation and a wholly-owned subsidiary of BANC. Merger Sub was incorporated for the sole purpose of effecting the first merger. Merger Sub will not conduct any activities other than those incidental to its formation, the execution of the merger agreement and the transactions contemplated by the merger agreement. Following the first merger, the separate corporate existence of Merger Sub will cease.

9701 Wilshire Boulevard, Suite 700

Beverly Hills, California 90212-2007

(310) 887-8500

PACW is a bank holding company headquartered in Los Angeles, California, with an executive office in Denver, Colorado, with one wholly-owned banking subsidiary, PACW Bank. PACW Bank is a relationship-based community bank focused on providing business banking and treasury management services to small, middle-market, and venture-backed businesses. PACW Bank offers a broad range of loan and lease and deposit products and services through full-service branches throughout California and in Durham, North Carolina and Denver, Colorado, and loan production offices around the country. As of June 30, 2023, PACW, together with its subsidiaries, had total assets of $38.3 billion, loans and leases, net of deferred fees, of $22.3 billion, total deposits of $27.9 billion and total stockholders’ equity of $2.5 billion.

PACW’s principal source of income is dividends from PACW Bank. PACW Bank is a state-chartered non-member bank and, as such, is regulated by the FDIC as its primary federal regulator and the California Department of Financial Protection and Innovation. In addition, PACW Bank is regulated by the Consumer Financial Protection Bureau with respect to compliance with certain consumer financial laws.

PACW Bank is currently a California state-chartered non-member bank. Subject to the completion of the mergers and prior to the completion of the bank merger, PACW Bank intends to become a member of the Federal Reserve System. PACW Bank becoming a member of the Federal Reserve System is subject to approval of the Federal Reserve. As a state member bank, PACW Bank’s primary federal bank regulator would become the Federal Reserve.

PACW common stock is traded on Nasdaq under the symbol “PACW.” The PACW depositary shares are currently listed on Nasdaq under the symbol “PACWP.” Additional information about PACW and its subsidiaries is included in the annexes to this joint proxy statement/prospectus. For additional information about PACW and its subsidiaries, please visit PACW’s website www.pacwestbancorp.com. The information provided on PACW’s website is not part of this joint proxy statement/prospectus and is not incorporated herein by reference. See the section entitled “Where You Can Find More Information” on page 216.

This section of the joint proxy statement/prospectus describes material aspects of the mergers and the investments. This summary may not contain all of the information that is important to you. You should carefully read this entire joint proxy statement/prospectus and the other documents we refer you to for a more complete understanding of the mergers and the investments. In addition, we incorporate important business and financial information about BANC into this document by reference and include important business and financial information about PACW in the annexes to this document. See the section entitled “Where You Can Find More Information” beginning on page 216.

Each of BANC’s and PACW’s respective board of directors has unanimously approved the merger agreement and the transactions contemplated thereby, including the combination and, in the case of the BANC board of directors, the investment agreements and the transactions contemplated thereby. The merger agreement provides that, on the terms and subject to the conditions set forth therein, Merger Sub will merge with and into PACW, with PACW as the surviving entity, which we refer to as the “first merger.” Immediately following the first merger, PACW will merge with and into BANC, with BANC as the surviving corporation, which we refer to as the “second merger.” We refer to the first merger and the second merger collectively as the “mergers.” Promptly following the second merger, PACW Bank will become a member bank of the Federal Reserve System, which we refer to as the “FRS Membership.” Promptly following the effectiveness of the FRS Membership, BANC N.A. will merge with and into PACW Bank, with PACW Bank continuing as the surviving bank, which we refer to as the “bank merger.” Following the bank merger, the surviving bank will operate under the “Banc of California” name and brand.

On the terms and subject to the conditions set forth in the merger agreement, at the effective time of the first merger, each holder of PACW common stock issued and outstanding immediately prior to the effective time of the first merger, except for shares of PACW common stock owned by PACW as treasury stock or owned by PACW, BANC or Merger Sub (subject to certain exceptions) will be entitled to receive 0.6569 of a share of BANC common stock for each share of PACW common stock held by such holder.

On the terms and subject to the conditions set forth in the merger agreement, at the second effective time, each share of the PACW preferred stock issued and outstanding immediately prior to the second effective time will be converted into the right to receive one share of the new BANC preferred stock and, upon such conversion, the PACW preferred stock will no longer be outstanding and will automatically be cancelled and will cease to exist as of the second effective time. Additionally, following the mergers, each outstanding PACW depositary share representing a 1/40th interest in a share of PACW preferred stock will become a BANC depositary share and will represent a 1/40th interest in a share of new BANC preferred stock.

On the terms and subject to the conditions set forth in the investment agreements, at the investment closing, the Investors will invest an aggregate of $400 million in exchange for the sale and issuance by BANC of approximately (a) 21.8 million shares of BANC common stock and (b) 10.8 million shares of BANC NVCE stock, in each case, at a purchase price of $12.30 per share. In addition, the Warburg Investors will receive warrants to purchase approximately 15.9 million shares of BANC NVCE stock, and the Centerbridge Investor will receive warrants to purchase approximately 3.0 million shares of BANC common stock, each with an exercise price of $15.375 per share, a 25% premium to the price paid by the Investors for BANC common stock and BANC NVCE stock. The warrants carry a term of seven years but are subject to mandatory exercise when the market price of BANC common stock reaches or exceeds $24.60 for 20 or more trading days during any 30-consecutive trading day period, a 100% premium to the price paid by the Investors for BANC common stock and BANC NVCE stock. Additionally, following the ninetieth (90th) day after the date of the Warburg investment closing and upon the written request of the Warburg Investors (or certain permitted transferees), the Warburg Investors (or such transferee) may exchange all or a portion of such person’s shares of BANC NVCE stock (including shares of BANC NVCE stock for which the warrants issued to the Warburg Investors may be exercised) for shares of BANC common stock or non-voting common stock of BANC, subject to certain conditions. See the section entitled “ Investment Agreements—Additional Warburg Investors Rights and Covenants—Covenants Regarding BANC NVCE Stock ” beginning on page 156 for more information.

See the sections entitled “The Merger Agreement” and “The Investment Agreements” for additional and more detailed information regarding the legal documents that govern the mergers and the investments, including

information about the conditions to the completion of the mergers and the investments and the provisions for terminating or amending the merger agreement and the investment agreements.

Under the merger agreement, although neither BANC’s nor PACW’s balance sheet repositioning is a condition to consummate the first merger, BANC and PACW commit to use reasonable best efforts to enter into agreements to complete the balance sheet repositioning at the best commercially reasonable available price, contingent upon the merger closing and either, as BANC and PACW reasonably determine, prior to the merger closing or effective as of, or as soon as reasonably practicable after, the merger closing. The information provided below is based on BANC and PACW’s current expectations and is not a guaranty or assurance that the balance sheet repositioning will be completed by the expected timing or on the terms described below. The amounts set forth below represent the best reasonable estimates of the BANC management team regarding the balance sheet repositioning activity as of the date of this joint proxy statement/prospectus. Accordingly, the actual amounts may vary depending on market conditions.

In connection with the balance sheet repositioning contingent upon the merger closing, as of the date of this joint proxy statement/prospectus, BANC and PACW plan to sell an aggregate of $7 billion of BANC and PACW assets, collectively, at or following closing, comprised of the following possible assets:

(i) $1.8 billion of its single-family residential mortgage portfolio

(ii) $1.6 billion of its multi-family residential mortgage portfolio

(iii) $1.2 billion of available-for-sale securities and held-to-maturity securities (“BANC bond portfolio”), which may include, among others, collateralized mortgage obligations (“CMO”), mortgage-backed securities (“MBS”), taxable municipal bonds and collateralized loan obligations (“CLO”)

Proceeds of the asset sales along with excess cash are expected to be utilized in the repayment of BANC and PACW’s $13 billion of wholesale borrowings, which include (1) $5.9 billion of brokered deposits of BANC and PACW, (2) $1.3 billion outstanding of PACW’s $1.4 billion repurchase agreement facility (“Repurchase Agreement Facility”), (3) $1.1 billion of FHLB borrowings by BANC and (4) $4.9 billion of Bank Term Funding Program (“BTFP”) borrowings by PACW. The repayment of these wholesale borrowings is contingent upon the completion of the balance sheet repositioning. The expected timing of the repayments is as follows:

The management of each of BANC and PACW and each of the BANC board of directors and the PACW board of directors frequently review their respective business strategies and objectives, including strategic opportunities and challenges. From time to time, the management teams and boards of directors of each of BANC and PACW have considered various strategic options potentially available to them, in each case with the goal of enhancing value for their respective stockholders and delivering the best possible services to their respective customers and communities. These strategic discussions have focused on, among other things, the business and regulatory environments facing financial institutions generally, as well as conditions and trends in the banking industry and financial markets, including for regional banks.

In January 2023, PACW announced a new strategic plan designed to maximize stockholder value and improve its liquidity position and capital ratios by strengthening its community bank business, exiting non-core products and services, improving capital and liquidity, and enhancing operational efficiency. Specifically, PACW made the decision to wind down operations in its premium finance and multi-family lending groups in the fourth quarter of 2022. In addition, PACW began planning for a restructuring of its Civic subsidiary in January 2023. Further, PACW sold $1.0 billion of available-for-sale securities at a loss in the fourth quarter of 2022 and used the proceeds to pay down borrowings from the Federal Home Loan Bank of San Francisco (“FHLB”). As part of its strategic plan, PACW also announced that it was slowing loan growth to preserve capital and strengthen its balance sheet. Around the time PACW announced this strategic plan, a combination of factors, including in particular the onset of higher interest rates, began to increase deposit funding costs and drove a general trend toward deposit outflows, particularly at regional banks.

While PACW intended to execute on this strategic plan throughout the course of 2023 and beyond, in early March 2023, the failures of Silicon Valley Bank and Signature Bank drew a significant degree of customer, market and regulatory focus to the state of the banking industry generally. A number of banks, including PACW, experienced further elevated deposit outflows in the days immediately following the failure of Silicon Valley Bank. In the days and weeks that followed the failures of Silicon Valley Bank and Signature Bank, PACW took a number of steps to ensure available liquidity for uninsured deposits by, among other things, pledging additional assets to and/or drawing on available federal facilities, including facilities with the FHLB and the Federal Reserve Discount Window and the Federal Reserve’s Bank Term Funding Program, and utilizing reciprocal deposit products (resulting in, in each case as of March 31, 2023, a borrowing capacity of $5.7 billion with the FHLB, of which $5.5 billion had been borrowed; borrowing capacity of $5.6 billion at the Federal Reserve Discount Window, all of which was available; and borrowing capacity under the Bank Term Funding Program of $4.9 billion, all of which had been borrowed). In addition, on March 17, 2023, PACW Bank entered into a $1.4 billion repurchase agreement facility, which was collateralized by loans in order to secure additional liquidity. In the two weeks following the failure of Silicon Valley Bank, PACW provided frequent updates to the market with respect to its financial position. Senior PACW management remained in regular communication with applicable federal and state regulators during this time.

Concurrently, the PACW board of directors and PACW management began evaluating various strategic alternatives for PACW and PACW Bank, including the potential of raising additional equity capital through a private placement or a registered public offering. With the assistance of representatives of PSC and a separate capital markets advisor, PACW engaged in discussions with prospective investors and ultimately entered into confidentiality agreements with three of these prospective investors during March and April 2023. Investors affiliated with the Warburg Investors were among these prospective investors, and the confidentiality agreement between PACW and Warburg Pincus LLC was entered into on March 12, 2023. Investors affiliated with the Centerbridge Investor were also among these prospective investors. Various potential investors conducted due diligence, and indicative terms and documentation were discussed. These discussions and negotiations progressed for approximately two weeks amidst the height of the volatility in the regional banking sector in March 2023.

PACW management frequently updated the PACW board of directors on the status of its operations and the potential equity capital alternatives. On March 20, 2023 and March 21, 2023, the PACW board of directors, other than Paul Taylor, President and Chief Executive Officer of PACW, met with members of PACW management, including Angela Kelley, Executive Vice President, General Counsel and Corporate Secretary of PACW, and Kevin Thompson, Executive Vice President and Chief Financial Officer of PACW, and representatives of PSC and Sullivan & Cromwell to review these potential equity capital alternatives and consider various proposals that had emerged from the discussions referenced above. Following further discussions with PSC and a separate capital markets advisor, and considering the volatility in the market and depressed market prices for regional bank stocks, as well as the availability of other options to enhance capital and liquidity through potential asset sales, the PACW board of directors determined on March 21, 2023 that it would not be prudent to move forward with any equity capital raising transaction at such time. PACW publicly announced this decision on March 22, 2023, along with providing an update on certain key deposit and liquidity metrics.

Following the announcement on March 22, 2023, the PACW board of directors and PACW management continued work to execute on the previously announced strategic plan to focus on its community bank business, in particular by pursuing strategic asset sales, while also evaluating potential broader strategic alternatives. In the weeks that followed, PACW, with the assistance of PSC, held discussions with a small number of parties it had contacted, or that had contacted it, with respect to potential acquisition or business combination transactions, including a party in which affiliates of the Warburg Investors have an interest.

On May 3, 2023, the entire PACW board of directors met with members of PACW management, including Mr. Taylor, Ms. Kelley and Mr. Thompson, to consider, among other matters, the status of these strategic discussions. In light of these discussions, the PACW board of directors determined that it would be in the best interests of PACW stockholders to approach and initiate discussions with a larger number of prospective strategic partners and instructed the representatives of PSC in attendance to do so. Representatives of Sullivan & Cromwell were also in attendance and advised members of the PACW board of directors with respect to their

fiduciary duties. Later that day, there were media reports that the PACW board of directors was reviewing strategic alternatives relating to the sale of some or all of the assets of PACW and PACW Bank. Following these reports, PACW Bank experienced additional deposit losses of approximately $1.7 billion on May 4 and May 5, 2023.

Over the next three weeks, the PACW board of directors met four times, with various members of PACW management, including Mr. Taylor, Ms. Kelley, Mr. Thompson, Christopher D. Blake, Executive Vice President, President and Chief Executive Officer of the Community Banking Group, Stanley R. Ivie, Executive Vice President, Chief Risk Officer, and Mark T. Yung, Executive Vice President, Chief Operating Officer, and provided updates on discussions with potential strategic partners as well as on the status of PACW’s operations.

Through the months of May and June, representatives of PSC, acting at the direction of the PACW board of directors and PACW management, contacted 13 potential acquirers and business combination partners, with ten of such parties entering into confidentiality agreements and conducting preliminary due diligence, including BANC who entered into a confidentiality agreement with PACW on May 4, 2023 (the “NDA”). One of the confidentiality agreements contained a standstill provision but did not contain a “don’t ask, don’t waive” provision; none of the other confidentiality agreements contained a standstill. Of the ten parties who conducted initial due diligence, two (which did not include BANC) indicated an interest in pursuing a potential all cash transaction.

On or about May 5, 2023, PACW indicated to BANC that its discussions with other parties were in more advanced stages. Therefore, from May 5, 2023 to about June 16, 2023, BANC and PACW ceased further discussions.

As noted above, PACW concurrently continued to execute on its strategic plan and on May 22, 2023, consistent with the objective to pursue strategic asset sales set out in such plan, PACW announced the sale of 74 real estate construction loans, with an aggregate commitment amount of approximately $5.3 billion, including an aggregate outstanding principal balance of $2.6 billion at the time of the announcement, to a wholly-owned subsidiary of Kennedy-Wilson Holdings, Inc.

On June 12, 2023, the PACW board of directors, other than Polly Jessen, met and Mr. Taylor, Mr. Thompson and Ms. Kelley provided an update on discussions with potential strategic partners. Mr. Taylor and Mr. Thompson summarized the discussions they had with various parties that had entered into confidentiality agreements and that two parties had expressed interest in an all cash acquisition of PACW. These two parties in particular had conducted the largest amount of due diligence to date and had preliminary discussions with PACW management about a potential transaction. Each was also provided with draft forms of definitive documentation to consider. While one of the two parties delivered to PACW on May 2, 2023 a very preliminary set of proposed terms, contemplating in general terms a proposed purchase price at or at a discount to market prices (without specifying a price), by the time of the June 12, 2023 meeting, discussions with these two parties had essentially ceased with neither delivering proposed definitive acquisition terms. Accordingly, at the time of the June 12, 2023 meeting, PACW was no longer in active discussions with any party regarding a potential strategic transaction. Management of PACW reported on these developments to the PACW board at the June 12 meeting, indicating that neither party was willing or able to commit the required capital to support the contemplated all cash acquisition transaction. Accordingly, PACW determined that a transaction would not be likely to be completed with either of the potential counterparties and continued its focus on executing on its strategic plan (subsequently, one of the two parties confirmed to PACW that it was unable to procure the required capital to continue consideration of a transaction). On June 22, 2023, and in connection with such strategic plan, PACW announced that PACW Bank had entered into a purchase agreement to sell a portfolio of lender finance loans with an aggregate commitment amount of $3.54 billion, including an aggregate outstanding principal balance of $2.21 billion as of the date of the announcement, to certain alternative credit strategy funds managed by Ares Management Corporation.

In mid-June, Jared Wolff, Chairman, President and Chief Executive Officer of BANC, remained interested in the prospects of a transaction with PACW. Recognizing that PACW had not at that time publicly announced an alternative transaction, Mr. Wolff reached out to Mr. Taylor and PSC, at which point Mr. Wolff learned that PACW was no longer pursuing a transaction with other parties. Therefore, on June 16, 2023, Mr. Wolff communicated to Mr. Taylor that BANC was interested in resuming, and inquired as to whether PACW was amenable to resuming discussions regarding a potential transaction. Thereafter, on or about June 16, 2023,

BANC management recommenced further due diligence on PACW. Mr. Wolff and Mr. Taylor remained in contact, discussing at a high level the possibility of a potential business combination transaction and the potential commercial and strategic benefits of a combination of their two businesses, among other things. In each of those conversations, they discussed that any potential transaction would reflect an “at market” exchange ratio.

In mid-June 2023, Mr. Wolff had various discussions with representatives of PACW, JPM and PSC regarding restarting negotiations for a potential transaction. In these discussions, the parties began to discuss in further detail the potential combined company’s business lines, markets of operation, potential synergies and efficiencies as well as the pro forma balance sheet, capital ratios, liquidity and deposit funding profile. The parties also provided updates with respect to the prospective transaction to federal and state regulatory authorities and continued to do so on a regular basis throughout the negotiation process. BANC management had also determined that, in order to proceed with a transaction with PACW, the potential combined company would require an infusion of equity capital.

From mid-June until the signing of the definitive transaction agreements and as set forth in more detail below in relation to specific discussions, Mr. Wolff and Mr. Taylor held a number of discussions on various topics related to the proposed transaction, including the exchange ratio, closing conditions, regulatory matters, governance matters, employment matters and interim operating covenants. At one such meeting, Mr. Wolff and Mr. Taylor discussed a proposal that the combined company’s board of directors would include eight currently serving directors of the BANC board of directors and three currently serving directors of the PACW board of directors (which board composition would be subject to the ongoing negotiations with prospective investors, though it was expected that likely one additional director representative would be selected by one of the prospective investors). Mr. Wolff and Mr. Taylor agreed to propose this construct to their respective boards of directors and that John Eggemeyer, the current Lead Director of the PACW board of directors, would be an advisable candidate to propose as the Chairman of the combined company’s board of directors, and did not otherwise identify which existing BANC or PACW board members would be included on the combined company board of directors.

On June 17, 2023, PACW made available to BANC, and on July 3, 2023, BANC made available to PACW, virtual data rooms to permit expanded mutual due diligence review. BANC and PACW, and their respective legal, financial and other advisors, engaged in mutual due diligence, including with respect to business, credit, operational, legal and compliance matters, among others. From approximately June 24 through July 11, 2023, BANC also negotiated and entered into confidentiality agreements with multiple potential investors, and certain potential investors entered into joinders to the NDA to facilitate their due diligence review for purposes of evaluating participation in the proposed equity financing. The Warburg Investors and the Centerbridge Investor entered into confidentiality agreements with BANC on June 23, 2023 and July 6, 2023, respectively (with the Centerbridge Investor further entering into a joinder to the NDA on July 10, 2023), and began to independently engage in due diligence with respect to PACW and BANC, including several meetings between the Warburg Investors, on the one hand, and BANC management or JPM, on the other hand, and several meetings between the Centerbridge Investor, on the one hand, and BANC management or JPM, on the other hand.

In the days leading up to the June 26, 2023 meeting of the BANC board of directors, as described below, Mr. Wolff connected regularly with all members of the BANC board of directors to provide updates on a potential strategic opportunity to engage in a business combination transaction with PACW.

On June 26, 2023, BANC held a special meeting of the BANC board of directors, attended by the entire BANC board of directors (other than Shannon Eusey), Ido Dotan, General Counsel and Corporate Secretary of BANC, Raymond Rindone, Chief Accounting Officer and Deputy Chief Financial Officer of BANC, and representatives of JPM and Skadden, to discuss the proposed transaction rationale, receive a financial, legal and regulatory overview of the proposed transaction, review the proposed non-binding indication of interest (the “LOI”) for a potential strategic combination between BANC and PACW to be submitted to PACW and appoint a transaction committee of the BANC board of directors, which we refer to as the “BANC transaction committee.” The BANC board of directors approved the LOI, and BANC submitted the LOI to PACW. The BANC board of directors also approved the formation of the BANC transaction committee and appointed members of the BANC transaction committee. The LOI proposed an all-stock merger based on an “at-market” fixed exchange ratio. It proposed a transaction structure in which BANC would be the legal acquirer at the holding company level, and PACW Bank would be the surviving bank and that the combined company would operate under the “Banc of California” name and brand. The LOI proposed that BANC would procure equity financing in connection with the proposed transaction of $350 million and that Mr. Wolff would lead the combined company as Chief

Executive Officer. The LOI also provided for a 45-day period in which PACW agreed to negotiate with BANC exclusively with respect to the potential transaction, with a potential for a 15-day extension of such period if the parties were negotiating in good faith regarding the proposed transaction. The LOI did not address any matters related to the governance of the combined company post-closing or any post-closing compensatory matters, other than Mr. Wolff’s position and the determination that the superior severance package between BANC and PACW would be paid to terminated employees after closing. Upon receipt of the LOI, Mr. Taylor discussed with representatives of PSC the terms of the LOI, after which Mr. Taylor informed Matthew Wagner, Executive Chairman of the PACW board of directors, and Mr. Eggemeyer, Lead Director of the PACW board of directors, of the LOI. Mr. Taylor then informed other members of PACW management and scheduled a call with the PACW board of directors and representatives of PSC and Sullivan & Cromwell to discuss the LOI.

Throughout the process, BANC and PACW continued to evaluate the optimal size of the capital raise based on continued financial due diligence and discussions with Investors.

On or about July 1, 2023, BANC and PACW increased the proposed equity financing from $350 million to $400 million committed by the Investors following further discussions between BANC and PACW based on their review of the financial model for the transaction and in order to bolster the financial strength of the combined company.

On June 28, 2023, the entire PACW board of directors met with members of PACW management, including Mr. Taylor, Ms. Kelley and Mr. Thompson, to review the results of the process, including to review the terms of the LOI. Representatives of PSC and Sullivan & Cromwell were also in attendance, and PSC presented on the business and financial aspects of the proposed transaction with BANC. The PACW board of directors then discussed with PACW management and PSC the strategic rationale, risks, financial metrics presented by a potential transaction with BANC and the potential value to the PACW stockholders resulting from such transaction. The PACW board of directors and PACW management also discussed the risks and regulatory considerations of the potential transaction with BANC relative to alternative strategic transactions, including continuing to search for other parties interested in such a transaction, as well as potentially electing not to pursue any strategic transaction, given the two remaining interested parties had become non-responsive or confirmed that they could not procure the required capital to support the contemplated all cash transaction. Following these discussions, the PACW board of directors was of the view that a potential transaction with BANC had a compelling strategic rationale and potential to provide meaningful benefits to PACW stockholders relative to other strategic alternatives and indicated its support for PACW proceeding with negotiations of the potential transaction with BANC.

On June 29, 2023, BANC and PACW executed the LOI and instructed their respective financial and legal advisors to begin work toward the potential transaction. Shortly thereafter, at the direction of BANC’s management, JPM initiated or reinitiated discussions with various prospective investors in connection with the proposed equity financing, including the Warburg Investors and the Centerbridge Investor.

BANC and PACW (principally through Mr. Wolff and Mr. Taylor) then, with the assistance of their respective advisors, discussed a variety of matters with respect to the potential transaction, including, without limitation, details regarding the governance and management of the combined company. Specifically, Mr. Wolff and Mr. Taylor discussed different potential numbers of each of BANC and PACW board members on the initial combined company board of directors, without agreeing on specific numbers, and held preliminary discussions concerning management roles for the combined company. In these discussions, Mr. Wolff and Mr. Taylor and the parties’ respective advisors also discussed the need for the two institutions to each engage in certain asset sales in order to enhance the combined company’s liquidity and capital ratios, without agreeing on specific investment securities or loan portfolios at that time. In addition, each party, with the assistance of their respective advisors, advanced their respective diligence reviews of the other party, and the Investors, with the assistance of their respective advisors, advanced their respective diligence reviews of BANC and PACW.

On July 11, 2023, Skadden sent the first draft of the merger agreement to Sullivan & Cromwell.

During July 2023, BANC, JPM and Skadden also discussed certain structural matters pertaining to the proposed equity financing with the Warburg Investors, along with Wachtell Lipton Rosen & Katz LLP (“Wachtell”), counsel to the Warburg Investors, and the Centerbridge Investor, along with Simpson Thacher & Bartlett LLP (“Simpson”), counsel to the Centerbridge Investor.

On July 13, 2023, the in-house and outside counsels of BANC and PACW had a conference call to discuss the merger agreement, including discussions on closing conditions, regulatory matters and termination rights.

The parties also continued their discussions around a method for measuring an “at market” fixed exchange ratio as set forth in the LOI. At the direction of BANC’s management, JPM communicated to PSC a proposal that the “at market” exchange ratio be based on the volume-weighted average price of BANC common stock and PACW common stock in the five trading days up to, and including, June 29, 2023, the date on which the LOI was executed by PACW and BANC. This was calculated to be 0.6569 shares of BANC common stock for each share of PACW common stock. PSC communicated this proposal to PACW.

On July 14, 2023, Sullivan & Cromwell sent a revised draft of the merger agreement to Skadden, which: (i) proposed a revised version of the definition of “materially burdensome regulatory condition” and made the related closing condition mutual, (ii) removed certain proposed conditions to closing and related termination rights, (iii) proposed a bylaw amendment to protect go forward governance rights for the PACW directors and (iv) proposed decreasing the termination fee from 5% of the deal value, as proposed in Skadden’s initial July 11 draft, to 3.9% of the deal value.

On July 14, 2023, BANC held a meeting of the BANC board of directors, attended by the entire BANC board of directors, Mr. Dotan, Mr. Rindone, Joseph Kauder, Chief Financial Officer of BANC, and representatives of JPM and Skadden, to discuss the status and timing of the proposed transaction, review such transaction and their vision for the combined company, review financial models for the proposed transaction, discuss legal structure and definitive agreements, discuss the capital raising process and legal components thereof, and receive updates on regulatory and key open issues.

On July 16, 2023, BANC and PACW agreed that the exchange ratio of 0.6569 of a share of BANC common stock for each share of PACW common stock adequately reflected the parties’ intention that the transaction would not involve any established premium or discount to any particular party’s stock price, and avoided the risk that any potential future market volatility (in light of recent market conditions) would lead to any unwanted distortions in the pricing of the transaction.

On July 17, 2023, BANC held a meeting of the BANC board of directors, attended by all directors, other than Mary Curran and Vania Schlogel, and Messrs. Dotan, Rindone and Kauder, where Mr. Wolff provided an update on the status and various aspects of the proposed transaction and the BANC board of directors asked questions and discussed the proposed transaction.

From July 17, 2023 until July 25, 2023, Skadden, Wachtell and Simpson exchanged multiple drafts of the Warburg investment agreement and the Centerbridge investment agreement, as applicable, and various ancillary documents.

On July 18, 2023, Mr. Wolff spoke with Mr. Eggemeyer to discuss the proposal for Mr. Eggemeyer to serve in the role of Chairman of the combined company’s board of directors.

On July 18, 2023, Skadden sent a revised draft of the merger agreement to Sullivan & Cromwell, which, among other things, (i) proposed a revised definition of “material adverse effect,” (ii) proposed the combined company’s board of directors to consist of (a) eight legacy BANC directors, (b) three legacy PACW directors and (c) one individual designated by the Warburg Investors and (iii) proposed the independent Lead Director of PACW to serve as the Chairman of the combined company’s board of directors and the Chairman of BANC N.A. to serve as the Chairman of the surviving bank.

On July 19, 2023, BANC held a meeting of the BANC transaction committee, attended by all committee members, Messrs. Dotan and Kauder and Connie Lam, Deputy General Counsel of BANC, with JPM and Skadden in attendance, to discuss the terms of the proposed investments by the Warburg Investors and the Centerbridge Investor, respectively.

On July 20, 2023, the entire PACW board of directors and members of PACW management, including Mr. Taylor, Mr. Thompson and Ms. Kelley, met with representatives of PSC and Sullivan & Cromwell present. Mr. Taylor and Mr. Thompson provided an update on the status of the negotiations and discussed with the PACW board of directors the due diligence conducted to that point. Management also discussed with the PACW board the effect of the proposed transaction on PACW’s existing compensation plans and arrangements.

On July 21, 2023, Sullivan & Cromwell sent a revised draft of the merger agreement, including (i) a revised definition of “material adverse effect”, (ii) proposing a revised definition of “materially burdensome regulatory condition” conceptually agreed to between PACW and BANC and (iii) removing the balance sheet repositioning as a mutual condition to closing, among other changes.

On July 22, 2023, BANC reached an agreement in principle with the Warburg Investors to invest a total of $325 million for common and/or common equivalent equity securities of BANC in the proposed equity financing and with the Centerbridge Investor to invest a total of $75 million for common securities of BANC in the proposed equity financing and that, in each case, certain warrants would be included with the investments. Based on the outcome of these discussions and the fixing of the exchange ratio, ownership of the common equity in the combined company at closing (excluding warrants or other equity awards) would be PACW stockholders with approximately 47% of the common shares outstanding in the combined company, BANC stockholders with approximately 34% of the common shares outstanding in the combined company and the Investors with approximately 19% of the common shares outstanding in the combined company (before the exercise of any of the warrants).

On July 24, 2023, the entire PACW board of directors held a meeting with members of PACW management in attendance, including Mr. Taylor, Mr. Thompson and Ms. Kelley, to consider the proposed terms of the transaction between PACW and BANC and the entry into the merger agreement by PACW, and representatives of Sullivan & Cromwell and PSC were in attendance. At the meeting, Mr. Taylor and Mr. Thompson provided an update on the results of the negotiations since the July 20, 2023 meeting of the PACW board of directors, reviewed the proposed terms of the transaction and advised of the remaining negotiation points that would need to be resolved prior to entering into a definitive agreement. Representatives of Sullivan & Cromwell provided members of the PACW board of directors with a summary of the proposed terms of the merger agreement, including certain negotiated terms of the merger agreement concerning the transaction’s closing conditions, and discussed the relationship between the closing conditions of the merger agreement and those in the investment agreements as well as certain executive compensation and benefits and employment-related matters.

On July 24, 2023, BANC held a meeting of the BANC board of directors, attended by the entire BANC board of directors, Messrs. Dotan, Kauder and Rindone, Debbie Dahl-Amundson, Chief Internal Audit Officer of BANC, Robert Dyck, Chief Credit Officer of BANC, Hamid Hussein, President of BANC N.A., Connie Lam, SVP, Deputy General Counsel of BANC; Olivia Lindsay, Chief Risk Officer of BANC, John Sotoodeh, Chief Operating Officer of BANC, and representatives of Skadden and JPM, to consider the proposed terms of the proposed transactions. During the meeting, the BANC board of directors discussed the major issues of the proposed transactions and terms of the definitive agreements, including the merger agreement and the investment agreements, treatment of employees and social issues. Members of BANC management provided an update on the final negotiation points and presented its view that from a documentation perspective the negotiations were effectively complete. JPM then reviewed the financial aspects of the mergers with the BANC board of directors and rendered its oral opinion to the BANC board of directors, which was confirmed by a written opinion, dated July 25, 2023, to the effect that, as of such date and based upon and subject to the factors and assumptions made, procedures followed, matters considered, and limitations and qualifications set forth in its opinion, the exchange ratio in the first merger was fair, from a financial point of view, to BANC. See the section entitled “ The Transactions—Opinion of BANC’s Financial Advisor. ” At the conclusion of the meeting, after further review and discussion by the BANC board of directors, including consideration of the factors described below under the section entitled “ The Transactions—BANC’s Reasons for the Mergers; Recommendation of the BANC Board of Directors ”, the BANC board of directors unanimously determined that the first merger was fair to, advisable and in the best interests of BANC and its stockholders and unanimously (a) determined that the merger agreement and the investment agreements, and the transactions contemplated thereby, were advisable and in the best interests of BANC and its stockholders and (b) approved the execution, delivery and performance of the merger agreement and the investment agreements, and the consummation of the transactions contemplated thereby (and the bank merger was also approved by the board of directors of BANC N.A. at a joint meeting with the BANC board of directors).

On July 25, 2023, the entire PACW board of directors held an additional meeting with members of PACW management in attendance, including Mr. Taylor, Mr. Thompson and Ms. Kelley, to consider the proposed transaction, and representatives of PSC and Sullivan & Cromwell were in attendance. Mr. Taylor and Mr. Thompson provided an update on the final negotiation points and presented its view that from a

documentation perspective the negotiations were effectively complete. PSC then reviewed the financial aspects of the mergers with the PACW board of directors and rendered its opinion to the PACW board of directors, which was initially rendered verbally and confirmed by a written opinion, dated July 25, 2023, to the effect that, as of such date and subject to the procedures followed, assumptions made, matters considered, and qualifications and limitations on the review undertaken by PSC as set forth in its opinion, the exchange ratio in the first merger was fair, from a financial point of view, to holders of PACW common stock. For more information, see the section entitled “The Transactions—Opinion of PACW’s Financial Advisor.” At the conclusion of the meeting, after further review and discussion by the PACW board of directors, including consideration of the factors described below under the section entitled “The Transactions—PACW’s Reasons for the Mergers; Recommendation of the PACW Board of Directors”, the PACW board of directors unanimously determined that the first merger was fair to, advisable and in the best interests of PACW and its stockholders and unanimously approved the merger agreement and the transactions contemplated thereby, including the mergers and the bank merger (and the bank merger was also approved by the board of directors of PACW Bank in a joint board capacity with the PACW board of directors) and entry into the merger agreement by PACW.

BANC and PACW executed the merger agreement, and BANC concurrently executed the applicable investment agreement with the Warburg Investors and the Centerbridge Investor, respectively, in the afternoon of July 25, 2023. The transactions were announced thereafter in a press release jointly issued by BANC and PACW on July 25, 2023.

After careful consideration, the BANC board of directors, at a special meeting held on July 24, 2023, unanimously (a) determined that the merger agreement and the investment agreements, and the transactions contemplated thereby, are advisable and in the best interests of BANC and its stockholders and (b) approved the execution, delivery and performance of the merger agreement and the investment agreements, and the consummation of the transactions contemplated thereby (and the bank merger was also approved by the board of directors of BANC N.A. at a joint meeting with the BANC board of directors).

In reaching this decision, the BANC board of directors evaluated the merger agreement, the mergers and the other matters contemplated by the merger agreement, as well as the investment agreements, in consultation with BANC’s senior management, as well as with BANC’s legal counsel and financial advisor, and considered a number of factors, including the following principal factors:

The BANC board of directors also considered potential risks related to the transaction. The BANC board of directors concluded that the anticipated benefits of combining with PACW and consummating the investments, which are described above, were likely to outweigh these risks. These potential risks include:

The foregoing discussion of the information and factors considered by the BANC board of directors is not intended to be exhaustive but includes the material factors considered by the BANC board of directors. In reaching its decision to approve the merger agreement and the investment agreements and the transactions contemplated thereby, the BANC board of directors did not quantify or assign any relative weights to the factors considered, and individual directors may have given different weights to different factors. The BANC board of directors considered all these factors as a whole, and overall considered the factors to support its determination.

For the reasons set forth above, the BANC board of directors determined that the merger agreement and the investment agreements, and the transactions contemplated thereby, are advisable and in the best interests of BANC and its stockholders. The BANC board of directors recommends that BANC stockholders vote “FOR” the BANC issuance proposal, “FOR” the BANC incentive plan proposal, “FOR” the BANC exemption amendment proposal and “FOR” the BANC adjournment proposal.

Certain of BANC’s directors and executive officers have other interests in the mergers that are different from, or in addition to, those of BANC stockholders generally, as discussed under the caption “The Transactions—Interests of Certain BANC Directors and Executive Officers in the Mergers” below. The BANC board of directors was aware of and considered these potential interests, among other matters, in evaluating the mergers and in making its recommendation to BANC stockholders.

It should be noted that this explanation of the reasoning of the BANC board of directors and all other information presented in this section is forward-looking in nature and, therefore, should be read in light of the future factors discussed in the section entitled “Cautionary Statement Regarding Forward-Looking Statements.”

In reaching its decision to approve the merger agreement and the transactions contemplated thereby, including the mergers, and to recommend that PACW stockholders adopt the merger agreement, the PACW board of directors reviewed and discussed with PACW’s management and with PACW’s financial and legal advisors the terms of the merger agreement and the transactions contemplated thereby, and considered a number of factors, including the following:

The PACW board of directors also considered potential risks related to the mergers but concluded that the anticipated benefits of the mergers were likely to outweigh these risks. These potential risks include:

The foregoing discussion of the information and factors considered by the PACW board of directors is not intended to be exhaustive but includes the material factors considered by the PACW board of directors. In reaching its decision to approve the merger agreement and the transactions contemplated thereby, including the mergers, the PACW board of directors did not quantify or assign any relative weights to the factors considered, and individual directors may have given different weights to different factors. The PACW board of directors considered all these factors as a whole, including through its discussions with PACW’s management and financial and legal advisors, in evaluating the merger agreement and the transactions contemplated thereby, including the mergers.

The PACW board of directors realized that there can be no assurance about future results, including results expected or considered in the factors listed above. It should be noted that this explanation of the reasoning of the PACW board of directors and all other information presented in this section is forward-looking in nature and, therefore, should be read in light of the future factors discussed in the section entitled “Cautionary Statement Regarding Forward-Looking Statements.” The PACW board of directors concluded, however, that the potential positive factors outweighed the potential risks of completing the mergers.

In considering the recommendation of the PACW board of directors, you should be aware that certain directors and executive officers of PACW may have interests in the mergers that are different from, or in addition to, interests of PACW stockholders generally and may create potential conflicts of interest. The PACW board of directors was aware of these interests and considered them when evaluating and negotiating the merger

agreement, the mergers and the other transactions contemplated by the merger agreement, and in recommending to PACW stockholders that they vote in favor of the PACW merger proposal. See the section entitled “The Transactions—Interests of Certain BANC Directors and Executive Officers in the Mergers” for more information.

For the reasons set forth above, the PACW board of directors unanimously determined that the first merger was fair to, advisable and in the best interests of PACW and its stockholders and unanimously approved the merger agreement and the transactions contemplated thereby, including the mergers and the bank merger (which was also approved by the board of directors of PACW Bank in a joint board capacity with the PACW board of directors) and entry into the merger agreement by PACW. The PACW board of directors recommends that PACW stockholders vote “FOR” the PACW merger proposal, “FOR” the PACW compensation proposal and “FOR” the PACW adjournment proposal.

Pursuant to an engagement letter, BANC retained JPM to act as its financial advisor in connection with the mergers. At the meeting of the BANC board of directors on July 24, 2023, JPM rendered its oral opinion to the BANC board of directors that, as of such date and based upon and subject to the factors and assumptions made, procedures followed, matters considered, and limitations and qualifications set forth in its opinion, the exchange ratio in the first merger was fair, from a financial point of view, to BANC. JPM has confirmed its July 24, 2023, oral opinion by delivering its written opinion to the BANC board of directors, dated July 25, 2023, that, as of such date, the exchange ratio in the first merger was fair, from a financial point of view, to BANC.

The full text of the written opinion of JPM, dated July 25, 2023, which sets forth, among other things, the assumptions made, matters considered and limits on the review undertaken, is attached as Annex O to this joint proxy statement/prospectus and is incorporated herein by reference. The summary of the opinion of JPM set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of such opinion. BANC stockholders are urged to read the opinion in its entirety. JPM’s written opinion was addressed to the BANC board of directors in connection with and for the purposes of its evaluation of the mergers, was directed only to the exchange ratio in the first merger and did not address any other aspect of the mergers. JPM expressed no opinion as to the fairness of the exchange ratio to the holders of any class of securities, creditors or other constituencies of BANC or as to the underlying decision by BANC to engage in the mergers. The issuance of JPM’s opinion was approved by a fairness committee of JPM. The summary of the opinion of JPM set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of such opinion. The opinion of JPM does not constitute a recommendation to any BANC stockholder as to how such stockholder should vote with respect to the mergers or any other matter.

In arriving at its opinion, JPM, among other things:

In addition, JPM held discussions with certain members of the management of PACW and BANC with respect to certain financial aspects of the mergers, and the past and current business operations of PACW and BANC, the financial condition and future prospects and operations of PACW and BANC, the effects of the mergers on the financial condition and future prospects of BANC, and certain other matters JPM believed necessary or appropriate to its inquiry.

In giving its opinion, JPM relied upon and assumed the accuracy and completeness of all information that was publicly available or was furnished to or discussed with JPM by PACW and BANC or otherwise reviewed by or for JPM. JPM did not independently verify any such information or its accuracy or completeness and, pursuant to its engagement letter with BANC, JPM did not assume any obligation to undertake any such independent verification. JPM did not conduct and was not provided with any valuation or appraisal of any assets or liabilities, nor did JPM evaluate the solvency of PACW or BANC under any state or federal laws relating to bankruptcy, insolvency or similar matters. JPM is not an expert in evaluating the adequacy of allowances for loan and lease losses of BANC or PACW with respect to their loan and lease portfolios and, accordingly, JPM did not make an independent evaluation of the adequacy of the allowance for loan and lease losses of BANC or PACW and JPM assumed, with BANC’s consent, that the respective allowances for loan and lease losses for both BANC and PACW, respectively, are adequate to cover such losses and will be adequate on a pro forma basis for the combined entity. In relying on the Financial Projections and the Synergies, JPM assumed with BANC’s consent that they were reasonably prepared based on assumptions reflecting the best currently available estimates and judgments by management of BANC as to the expected future results of operations and financial condition of PACW and BANC to which such analyses or forecasts relate or, in the case of the BANC projections, that they represent a reasonable basis upon which to evaluate the expected future results of operations and financial condition of BANC. On that basis, in giving its opinion, JPM assumed the accuracy of such analyses and forecasts (including the Synergies) and JPM expressed no view as to the accuracy of such analyses or forecasts (including the Synergies) or the assumptions on which they were based. In addition, JPM assumed that the proposed equity financing from the Warburg Investors and the Centerbridge Investor or certain other investors, balance sheet repositioning and sale of non-core businesses will occur on the terms and in the time frame described by management of BANC. JPM also assumed that the mergers and the other transactions contemplated by the merger agreement will qualify as a tax-free reorganization for U.S. federal income tax purposes and will be consummated as described in the merger agreement, and that the definitive merger agreement would not differ in any material respects from the draft thereof furnished to JPM. JPM also assumed that the representations and warranties made by BANC and PACW in the merger agreement and the related agreements were and will be true and correct in all respects material to its analysis. JPM is not a legal, regulatory or tax expert and relied on the assessments made by advisors to BANC with respect to such issues. JPM further assumed that all material governmental, regulatory or other consents and approvals necessary for the consummation of the mergers will be obtained without any adverse effect on PACW or BANC or on the contemplated benefits of the mergers.

The BANC projections reviewed and relied upon by JPM were derived from a consensus of selected Wall Street research analysts that were identified by BANC’s management and, with the guidance and assistance of BANC’s management, extrapolated for the fiscal years ended 2025-2028, and the PACW projections reviewed and relied upon by JPM were prepared by PACW’s management. PACW does not publicly disclose internal management projections of the type provided to JPM in connection with JPM’s analysis of the mergers, and such projections were not prepared with a view toward public disclosure. The Synergies reviewed and relied upon by JPM were provided by BANC management and reflected BANC management’s go-forward operating plan for the pro forma company, including the merger adjustments described in the section entitled “ Certain Estimated Synergies Attributable to the Mergers ” of this joint proxy statement/prospectus. The Financial Projections were based on numerous variables and assumptions that are inherently uncertain and may be beyond the control of BANC’s and PACW’s respective managements, including factors related to general economic and competitive conditions and prevailing interest rates. Accordingly, actual results could vary significantly from those set forth in such

projections. For more information and certain other important disclosures, limitations and qualifications regarding the use of projections and other forward-looking statements, please refer to the section entitled “Certain Unaudited Prospective Financial Information” of this joint proxy statement/prospectus.

JPM’s opinion was necessarily based on economic, market and other conditions as in effect on, and the information made available to JPM as of, the date of such opinion. JPM’s opinion noted that subsequent developments may affect JPM’s opinion and that JPM does not have any obligation to update, revise, or reaffirm such opinion. Furthermore, JPM expressed no opinion with respect to the amount or nature of any compensation to any officers, directors, or employees of any party to the mergers, or any class of such persons relative to the exchange ratio in the first merger or with respect to the fairness of any such compensation. JPM expressed no opinion as to the price at which the PACW common stock or BANC common stock will trade at any future time.

The terms of the merger agreement, including the exchange ratio, were determined through arm’s length negotiations between BANC and PACW, and the decision to enter into the merger agreement was solely that of the BANC board of directors and the PACW board of directors. JPM’s opinion and financial analyses were only one of the many factors considered by the BANC board of directors in its evaluation of the mergers and should not be viewed as determinative of the views of the BANC board of directors or management with respect to the mergers or the exchange ratio.

In accordance with customary investment banking practice, JPM employed generally accepted valuation methodology in rendering its written opinion to the BANC board of directors on July 25, 2023, and contained in the presentation delivered to the BANC board of directors on July 24, 2023 in connection with the rendering of such opinion and does not purport to be a complete description of the analyses or data presented by JPM. Some of the summaries of the financial analyses include information presented in tabular format. The tables are not intended to stand alone, and in order to more fully understand the financial analyses used by JPM, the tables must be read together with the full text of each summary. Considering the data set forth below without considering the full narrative description of the financial analyses, including the methodologies and assumptions underlying the analyses, could create a misleading or incomplete view of JPM’s analyses.

Using publicly available information, JPM compared selected financial data of PACW with similar data for selected publicly traded companies engaged in businesses that JPM judged to be analogous to PACW (collectively, referred to in this section as the “PACW selected companies”). The companies selected by JPM were:

These companies were selected by JPM because of similarities to PACW in one or more of their business characteristics and, in certain cases, similarities to PACW based on certain operational characteristics and/or certain financial metrics. However, none of the PACW selected companies is identical or directly comparable to PACW, and certain of the companies may have characteristics that are materially different from those of PACW. Accordingly, a complete analysis of the results of the following calculations cannot be limited to a quantitative review of such results and involves complex considerations and judgments concerning the differences in the financial and operating characteristics of the PACW selected companies compared to PACW and other factors that could affect the public trading value of the PACW selected companies and PACW.

In all instances, multiples were based on closing stock prices on July 21, 2023, which was the last practicable day prior to the delivery of the JPM opinion. For each of the following analyses performed by JPM, financial data for the PACW selected companies were based on the PACW selected companies’ public filings and information JPM obtained from S&P Global Market Intelligence and FactSet Research Systems. The multiples and ratios for each of the PACW selected companies were based on the most recent publicly available information.

With respect to the PACW selected companies, publicly available financial information as of March 31, 2023 was measured. With respect to PACW and the PACW selected companies, the information JPM presented included:

in each case, based on reported metrics and available estimates obtained from public filings, S&P Global Market Intelligence and FactSet Research Systems and/or the PACW projections.

Based on the results of this analysis and other factors which JPM considered appropriate based on its experience and judgment, JPM selected multiple reference ranges for PACW as follows:

Based on the above analysis, JPM then applied a multiple reference range of 5.8x to 15.8x for 2024E P/E to PACW’s estimated earnings per share for the fiscal year 2024 of $1.12 as set forth in the PACW projections. JPM also applied a multiple reference range of 0.93x to 1.00x for the P/TBV regression, which it derived from the estimated range of PACW’s 2024E ROATCE of 5.8% to 7.8% as derived from the PACW projections to PACW’s tangible book value per share of $18.66, based on the most recent publicly available financial information as of March 31, 2023.

After applying these ranges to PACW’s estimated 2024 earnings per share and PACW’s tangible book value per share, JPM’s analysis indicated the following implied equity value per share ranges for the shares of PACW common stock, as compared to the closing price of PACW common stock of $9.71 on July 21, 2023.

JPM calculated a range of implied values for PACW common stock by discounting to present value estimates of PACW’s future dividend stream and terminal value. In performing its analysis, JPM utilized, among others, the following assumptions, which were reviewed and approved by BANC’s management:

Based on the PACW projections and using a range of discount rates from 10.0% to 12.0%, reflecting estimates of PACW’s cost of equity as described above, JPM discounted the estimated dividend streams from PACW for the period of the fourth quarter of 2023 and calendar years 2024 through 2027 and the range of terminal values as of December 31, 2027 to derive present values, as of September 30, 2023, of PACW.

These calculations resulted in a range of implied values of $10.75 to $13.68 per share of PACW common stock, as compared to the closing price of PACW common stock of $9.71 on July 21, 2023.

Using publicly available information, JPM compared selected financial data of BANC with similar data for selected publicly traded companies engaged in businesses that JPM judged to be analogous to BANC (collectively, referred to in this section as the “BANC selected companies”). The companies selected by JPM were:

These companies were selected by JPM because of similarities to BANC in one or more of their business characteristics and, in certain cases, similarities to BANC based on certain operational characteristics and/or certain financial metrics. However, none of the BANC selected companies is identical or directly comparable to BANC, and certain of the companies may have characteristics that are materially different from those of BANC. Accordingly, a complete analysis of the results of the following calculations cannot be limited to a quantitative review of such results and involves complex considerations and judgments concerning the differences in the financial and operating characteristics of the BANC selected companies compared to BANC and other factors that could affect the public trading value of the BANC selected companies and BANC.

In all instances, multiples were based on closing stock prices on July 21, 2023, which was the last practicable day prior to the delivery of the JPM opinion. For each of the following analyses performed by JPM, financial data for the BANC selected companies were based on the BANC selected companies’ public filings and information JPM obtained from S&P Global Market Intelligence and FactSet Research Systems. The multiples and ratios for each of the BANC selected companies were based on the most recent publicly available information.

With respect to the BANC selected companies, publicly available financial information as of March 31, 2023 was measured. With respect to BANC and the BANC selected companies, the information JPM presented included 2024 P/E and a P/TBV regression, in each case, based on reported metrics and available estimates obtained from public filings, S&P Global Market Intelligence, FactSet Research Systems and/or the BANC projections.

Based on the results of this analysis and other factors which JPM considered appropriate based on its experience and judgment, JPM selected multiple reference ranges for BANC as follows:

Based on the above analysis, JPM then applied a multiple reference range of 8.2x to 11.4x for 2024E P/E to BANC’s estimated earnings per share for the fiscal year 2024 of $1.42 as set forth in the BANC projections. JPM also applied a multiple reference range of 0.72x to 0.97x for the P/TBV regression, which it derived from the estimated range of BANC’s 2024E ROATCE of 8.0% to 10.0% as derived from the BANC projections to BANC’s tangible book value per share of $14.26, based on the most recent publicly available financial information as of March 31, 2023.

Applying these ranges to BANC’s estimated 2024E earnings per share and BANC’s tangible book value per share, JPM’s analysis indicated the following implied equity value per share ranges for the shares of BANC common stock, as compared to the closing price of BANC common stock of $12.79 on July 21, 2023.

JPM calculated a range of implied values for BANC common stock by discounting to present value estimates of BANC’s future dividend stream and terminal value. In performing its analysis, JPM utilized, among others, the following assumptions, which were reviewed and approved by BANC’s management:

Based on the BANC projections and using a range of discount rates from 7.5% to 9.5%, reflecting estimates of BANC’s cost of equity as described above, JPM discounted the estimated dividend streams from BANC for the period of the fourth quarter of 2023 and calendar years 2024 through 2027 and the range of terminal values as of December 31, 2027 to derive present values, as of September 30, 2023, of BANC.

These calculations resulted in a range of implied values of $16.38 to $19.32 per share of BANC common stock, as compared to the closing price of BANC common stock of $12.79 on July 21, 2023.

Based upon the implied valuations for each of PACW and BANC as derived above under “PACW Public Trading Multiples Analysis,” “—PACW Standalone Dividend Discount Analysis,” “—BANC Public Trading Multiples Analysis” and “—BANC Standalone Dividend Discount Analysis,” JPM calculated a range of implied exchange ratios of a share of PACW common stock to a share of BANC common stock, and then compared that range of implied exchange ratios to the exchange ratio.

For each of the analyses referred to above, JPM calculated the ratio implied by dividing the low end of each range of implied equity values of PACW by the high end of each range of implied equity values of BANC. JPM also calculated the ratio implied by dividing the high end of each range of implied equity values of PACW by the low end of each range of implied equity values of BANC. In each case, the implied exchange ratios were compared to the exchange ratio. This analysis indicated the following implied exchange ratios:

JPM compared these ranges of implied exchange ratios to the exchange ratio of 0.6569x.

At BANC management’s direction and based on the Financial Projections and the Synergies, PACW and BANC public filings, S&P Global Market Intelligence and FactSet, JPM prepared a value creation analysis that compared the equity value of BANC (based on the standalone dividend discount analysis) to the BANC stockholders’ portion of the pro forma combined company equity value, taking into consideration the pro forma ownership of the Warburg Investors and the Centerbridge Investor (including the impact of the warrants on a net

settlement basis). JPM determined the pro forma combined company equity value by calculating the sum of (i) the equity value of BANC using the midpoint value determined in JPM’s dividend discount analysis described above in “BANC Standalone Dividend Discount Analysis” (referred to in this section as the “BANC standalone value”), (ii) the equity value of PACW derived using the midpoint value determined in JPM’s dividend discount analysis described above in “PACW Standalone Dividend Discount Analysis” and (iii) the net present value of the Synergies according to BANC management’s forward operating plan. The value creation analysis, at the exchange ratio, yielded accretion to the holders of BANC common stock of 35.0% as compared to the BANC standalone value. There can be no assurance that the Synergies will not be substantially greater or less than the estimates described above.

JPM also reviewed and presented other information, solely for informational purposes, including:

The foregoing summary of certain material financial analyses does not purport to be a complete description of the analyses or data presented by JPM. The preparation of a fairness opinion is a complex process and is not necessarily susceptible to partial analysis or summary description. JPM believes that the foregoing summary and its analyses must be considered as a whole and that selecting portions of the foregoing summary and these analyses, without considering all of its analyses as a whole, could create an incomplete view of the processes underlying the analyses and its opinion. As a result, the ranges of valuations resulting from any particular analysis or combination of analyses described above were merely utilized to create points of reference for analytical purposes and should not be taken to be the view of JPM with respect to the actual value of BANC or PACW. The order of analyses described does not represent the relative importance or weight given to those analyses by JPM. In arriving at its opinion, JPM did not attribute any particular weight to any analyses or factors considered by it and did not form an opinion as to whether any individual analysis or factor (positive or negative), considered in isolation, supported or failed to support its opinion. Rather, JPM considered the totality of the factors and analyses performed in determining its opinion.

Analyses based upon forecasts of future results are inherently uncertain, as they are subject to numerous factors or events beyond the control of the parties and their advisors. Accordingly, forecasts and analyses used or made by JPM are not necessarily indicative of actual future results, which may be significantly more or less favorable than suggested by those analyses. Moreover, JPM’s analyses are not and do not purport to be appraisals or otherwise reflective of the prices at which businesses actually could be acquired or sold. None of the selected companies reviewed as described in the above summary is identical to BANC or PACW. However, the companies selected were chosen because they are publicly traded companies with operations and businesses that, for purposes of JPM’s analysis, may be considered similar to those of BANC or PACW.

As a part of its investment banking business, JPM and its affiliates are continually engaged in the valuation of businesses and their securities in connection with mergers and acquisitions, investments for passive and control purposes, negotiated underwritings, secondary distributions of listed and unlisted securities, private placements, and valuations for corporate and other purposes. JPM was selected to advise BANC with respect to the mergers on the basis of, among other things, such experience and its qualifications and reputation in connection with such matters and its familiarity with BANC, PACW and the industries in which they operate.

For services rendered in connection with the mergers, BANC has agreed to pay JPM a mergers and acquisitions advisory fee of $12,000,000, $2,000,000 of which became payable upon the delivery of JPM’s opinion and the

remainder of which will become payable only upon consummation of the mergers. Separately, for services rendered in connection with the equity financing, BANC has agreed to pay JPM a capital markets placement fee of $14,000,000, which will become payable upon consummation of the equity financing. In addition, BANC has agreed to reimburse JPM for its costs and expenses incurred in connection with its services, including the fees and disbursements of counsel, and will indemnify JPM against certain liabilities arising out of JPM’s engagement.

During the two years preceding the date of JPM’s opinion, neither JPM nor its affiliates have had material financial advisory or other material commercial or investment banking relationships with BANC or PACW. In addition, as part of the balance sheet repositioning transactions planned in connection with the mergers, affiliates of JPM are acting as counterparties to BANC in connection with (i) the purchase of a residential mortgage portfolio which is conditioned upon completion of the mergers and (ii) certain interest rate hedging transactions for which JPM has received customary fees. The total value of those transactions to JPM will depend on market conditions at the time the mergers are completed and certain future events and therefore cannot be calculated at this time. During the two year period preceding delivery of its opinion dated July 25, 2023, the aggregate fees recognized by JPM from BANC were approximately $150,000 and from PACW were approximately $3.5 million. During the two years preceding the date of JPM’s opinion, JPM and its affiliates have had commercial or investment banking relationships with the Warburg Investors and their affiliates, for which JPM and such affiliates have received customary compensation. Such services during such period have included acting as sole financial advisor on the acquisition by Warburg Pincus LLC of Exeter Finance LLC in November 2021, as joint lead bookrunner on a bond offering in October 2022 and as lead arranger and bookrunner on a credit facility in November 2022. During the two years preceding the date of JPM’s opinion, JPM and its affiliates have had commercial or investment banking relationships with portfolio companies of Warburg Pincus LLC, for which JPM and such affiliates have received customary compensation. Such services during such period have included providing debt syndication, equity underwriting, debt underwriting and financial advisory services to portfolio companies of Warburg Pincus LLC. In addition, during the two years preceding the date of JPM’s opinion, JPM and its affiliates have had commercial or investment banking relationships with certain portfolio companies of Centerbridge Partners, L.P., for which JPM and such affiliates have received customary compensation. Such services during such period have included providing debt syndication, equity underwriting and debt underwriting to certain portfolio companies of Centerbridge Partners, L.P. JPM’s commercial banking affiliate is an agent bank and a lender under outstanding credit facilities of Warburg Pincus LLC and its portfolio companies and Centerbridge Partners, L.P. and its portfolio companies for which it receives customary compensation or other financial benefits. In addition, JPM and its affiliates hold, on a proprietary basis, less than 1% of the outstanding common stock of each of BANC and PACW. In the ordinary course of their businesses, JPM and its affiliates may actively trade the debt and equity securities or financial instruments (including derivatives, bank loans or other obligations) of BANC or PACW for their own accounts or for the accounts of customers and, accordingly, they may at any time hold long or short positions in such securities or other financial instruments.

PACW retained PSC to act as financial advisor to the PACW board of directors in connection with PACW’s consideration of a possible business combination with BANC. PACW selected PSC to act as its financial advisor because PSC is a nationally recognized investment banking firm whose principal business specialty is financial institutions. In the ordinary course of its investment banking business, PSC is regularly engaged in the valuation of financial institutions and their securities in connection with mergers and acquisitions and other corporate transactions.

PSC acted as financial advisor to the PACW board of directors in connection with the mergers and participated in certain of the negotiations leading to the execution of the merger agreement. At the July 25, 2023 meeting at which the PACW board of directors considered the mergers and the merger agreement, PSC delivered to the PACW board of directors its oral opinion, which was subsequently confirmed in writing on July 25, 2023, to the effect that, as of such date, the exchange ratio in the first merger was fair to the holders of PACW’s common stock from a financial point of view. The full text of PSC’s opinion is attached as Annex P to this joint proxy statement/prospectus. The opinion outlines the procedures followed, assumptions made, matters considered and qualifications and limitations on the review undertaken by PSC in rendering its opinion. The description of the opinion set forth below is qualified in its entirety by reference to the full text of the opinion. Holders of PACW common stock are urged to read the entire opinion carefully in connection with their consideration of the proposed first merger.

PSC’s opinion was directed to the PACW board of directors in connection with its consideration of the mergers and the merger agreement and does not constitute a recommendation to any PACW stockholder as to how any such stockholder should vote at any meeting of stockholders called to consider and vote upon the approval of the first merger and the merger agreement. PSC’s opinion was directed only to the fairness, from a financial point of view, of the exchange ratio to the holders of PACW common stock and did not address the underlying business decision of PACW to engage in the mergers, the form or structure of the mergers or any other transactions contemplated in the merger agreement, the relative merits of the mergers as compared to any other alternative transactions or business strategies that might exist for PACW or the effect of any other transaction in which PACW might engage. PSC also did not express any opinion as to the fairness of the amount or nature of the compensation to be received in the first merger by any officer, director or employee of, or any class of such persons, if any, relative to the compensation to be received in the first merger by any other stockholder. PSC’s opinion was approved by PSC’s fairness opinion committee.

In connection with its opinion, PSC reviewed and considered, among other things:

PSC also discussed with certain members of the senior management of PACW and its representatives the business, financial condition, results of operations and prospects of PACW and held similar discussions with certain members of the management of BANC and its representatives regarding the business, financial condition, results of operations and prospects of BANC.

In performing its review, PSC relied upon the accuracy and completeness of all of the financial and other information that was available to and reviewed by PSC from public sources, that was provided to PSC by PACW or BANC or their respective representatives, or that was otherwise reviewed by PSC, and PSC assumed such accuracy and completeness for purposes of rendering its opinion without any independent verification or investigation. PSC relied on the assurances of the respective managements of PACW and BANC that they were not aware of any facts or circumstances that would have made any of such information inaccurate or misleading. PSC was not asked to and did not undertake an independent verification of any of such information and PSC did not assume any responsibility or liability for the accuracy or completeness thereof. PSC did not make an independent evaluation or perform an appraisal of the specific assets, the collateral securing assets or the liabilities (contingent or otherwise) of PACW or BANC, nor was PSC furnished with any such evaluations or appraisals. PSC rendered no opinion or evaluation on the collectability of any assets or the future performance of any loans of PACW or BANC, nor any of their respective subsidiaries. PSC did not make an independent evaluation of the adequacy of the allowance for loan losses of PACW or BANC, any of their respective subsidiaries or the combined company after the mergers, and PSC did not review any individual credit files relating to PACW or BANC or any of their respective subsidiaries. PSC assumed, with PACW’s consent, that the respective allowances for loan losses for both PACW and BANC were adequate to cover such losses and would be adequate on a pro forma basis for the combined company.

In preparing its analyses, PSC used internal financial projections for PACW for the years ending December 31, 2023 through December 31, 2025, as provided by the senior management of PACW. In addition, PSC used publicly available mean analyst earnings per share estimates for BANC for the quarters ending September 30, 2023 and December 31, 2023 and the year ending December 31, 2024, as well as an estimated long-term annual earnings per share growth rate for the year ending December 31, 2025 and dividends per share for the years ending December 31, 2023 through December 31, 2025, as provided by the senior management of BANC and its representatives. PSC also received and used in its pro forma analyses certain assumptions relating to operating profile as provided by the senior management of BANC and its representatives, including with respect to transaction expenses, cost savings, purchase accounting adjustments, certain assumptions for CECL accounting standards, as well as certain balance sheet assumptions, including the offer and sale of a certain amount of common stock by BANC concurrent with the merger closing to the Warburg Investors and the Centerbridge Investor in the investments. With respect to the foregoing information, the respective senior managements of PACW and BANC confirmed to PSC that such information reflected (or, in the case of the publicly available analyst estimates referred to above, were consistent with) the best currently available projections, estimates and judgments of those respective managements as to the future financial performance of PACW and BANC, respectively, and PSC assumed that the financial results reflected in such information would be achieved. PSC expressed no opinion as to such projections, estimates or judgements, or the assumptions on which they were based. PSC also assumed that there had been no material change in the respective assets, financial condition, results of operations, business or prospects of PACW or BANC since the date of the most recent financial statements made available to PSC. PSC assumed in all respects material to its analyses that PACW and BANC would remain as going concerns for all periods relevant to its analyses.

PSC also assumed, with PACW’s consent, that (i) each of the parties to the merger agreement would comply in all material respects with all material terms and conditions of the merger agreement and all related agreements, that all of the representations and warranties contained in such agreements were true and correct in all material respects, that each of the parties to such agreements would perform in all material respects all of the covenants and other obligations required to be performed by such party under such agreements and that the conditions precedent in such agreements were not and would not be waived, (ii) in the course of obtaining the necessary regulatory or third party approvals, consents and releases with respect to the mergers, no delay, limitation, restriction or condition would be imposed that would have an adverse effect on PACW, BANC, the mergers or any related transactions, and (iii) the mergers and any related transactions would be consummated in accordance

with the terms of the merger agreement without any waiver, modification or amendment of any material term, condition or agreement thereof and in compliance with all applicable laws and other requirements. PSC expressed no opinion as to any legal, accounting or tax matters relating to the mergers and the other transactions contemplated by the merger agreement.

PSC’s opinion was necessarily based on financial, economic, regulatory, market and other conditions as in effect on, and the information made available to PSC as of, the date thereof. Events occurring after the date thereof could materially affect PSC’s opinion. PSC has not undertaken to update, revise, reaffirm or withdraw its opinion or otherwise comment upon events occurring after the date thereof. PSC expressed no opinion as to the trading value of PACW common stock or BANC common stock at any time or what the value of BANC common stock will be once the shares are actually received by the holders of PACW common stock.

In rendering its opinion, PSC performed a variety of financial analyses. The summary below is not a complete description of all the analyses underlying PSC’s opinion or the presentation made by PSC to the PACW board of directors, but is a summary of the material analyses performed and presented by PSC. The summary includes information presented in tabular format. In order to fully understand the financial analyses, these tables must be read together with the accompanying text. The tables alone do not constitute a complete description of the financial analyses. The preparation of a fairness opinion is a complex process involving subjective judgments as to the most appropriate and relevant methods of financial analysis and the application of those methods to the particular circumstances. The process, therefore, is not necessarily susceptible to a partial analysis or summary description. PSC believes that its analyses must be considered as a whole and that selecting portions of the factors and analyses to be considered without considering all factors and analyses, or attempting to ascribe relative weights to some or all such factors and analyses, could create an incomplete view of the evaluation process underlying its opinion. Also, no company included in PSC’s comparative analyses described below is identical to PACW or BANC and no transaction is identical to the mergers. Accordingly, an analysis of comparable companies or transactions involves complex considerations and judgments concerning differences in financial and operating characteristics of the companies and other factors that could affect the public trading values or transaction values, as the case may be, of PACW and BANC and the companies to which they were compared. In arriving at its opinion, PSC did not attribute any particular weight to any analysis or factor that it considered. Rather, PSC made qualitative judgments as to the significance and relevance of each analysis and factor. PSC did not form an opinion as to whether any individual analysis or factor (positive or negative) considered in isolation supported or failed to support its opinion; rather, PSC made its determination as to the fairness of the exchange ratio to the holders of PACW common stock on the basis of its experience and professional judgment after considering the results of all its analyses taken as a whole.

In performing its analyses, PSC also made numerous assumptions with respect to industry performance, business and economic conditions and various other matters, many of which cannot be predicted and are beyond the control of PACW, BANC, and PSC. The analyses performed by PSC are not necessarily indicative of actual values or future results, both of which may be significantly more or less favorable than suggested by such analyses. PSC prepared its analyses solely for purposes of rendering its opinion and provided such analyses to the PACW board of directors at its July 25, 2023 meeting. Estimates on the values of companies do not purport to be appraisals or necessarily reflect the prices at which companies or their securities may actually be sold. Such estimates are inherently subject to uncertainty and actual values may be materially different. Accordingly, PSC’s analyses do not necessarily reflect the value of PACW common stock or BANC common stock or the prices at which PACW or BANC common stock may be sold at any time. The analyses of PSC and its opinion were among a number of factors taken into consideration by the PACW board of directors in making its determination to approve the merger agreement and the analyses described below should not be viewed as determinative of the decision of the PACW board of directors with respect to the fairness of the exchange ratio.

PSC reviewed the financial terms of the first merger. Pursuant to the terms of the merger agreement, at the effective time each share of PACW common stock issued and outstanding immediately prior to the effective time, except for certain shares as set forth in the merger agreement, shall be converted into the right to receive 0.6569 of a share of BANC common stock. PSC calculated an aggregate implied transaction value of approximately $1,014 million and an implied purchase price per share of $8.40 consisting of the implied value of 120,011,310 shares of PACW common stock and 656,049 performance stock units of PACW based on the closing price of BANC common stock on July 21, 2023. Based upon financial information for PACW as of or

for the last twelve months (“LTM”) ended June 30, 2023, and the closing price of PACW’s common stock on July 21, 2023, PSC calculated the following implied transaction metrics:

PSC reviewed the relative contribution of PACW and BANC to the pro forma balance sheet and income of the combined company. This analysis excluded mark-to-market and other transaction-related adjustments. The results of this analysis are set forth in the following table, which also compares the results of this analysis with the implied pro forma ownership percentages of PACW and BANC stockholders in the combined company, with pricing data as of July 21, 2023:

PSC reviewed the publicly available historical reported trading prices of PACW common stock and BANC common stock for the one-year and three-year periods ended July 21, 2023. PSC then compared the relationship between the movements in the price of PACW common stock and BANC common stock, respectively, to movements in their respective peer groups (as described below) as well as certain stock indices.