You are cordially invited to attend a virtual special meeting (including any adjournments or postponements thereof, the “Special Meeting”) of stockholders of Cornerstone OnDemand, Inc. (“Cornerstone” or the “Company”) to be held virtually on October 12, 2021, at 8:00 a.m. Pacific time at www.virtualshareholdermeeting.com/CSOD2021SM.

At the Special Meeting, you will be asked to consider and vote on (i) a proposal to adopt the Agreement and Plan of Merger, dated August 5, 2021 (such agreement, as it may be amended, modified or supplemented from time to time, the “Merger Agreement”), by and among Cornerstone, Sunshine Software Holdings, Inc., a Delaware corporation (“Parent”), and Sunshine Software Merger Sub, Inc., a Delaware corporation (“Merger Sub”), (ii) a proposal to approve, on an advisory (non-binding) basis, the compensation that may be paid or become payable to Cornerstone’s named executive officers that is based on or otherwise relates to the Merger Agreement and the transactions contemplated by the Merger Agreement (the “Compensation Proposal”), and (iii) a proposal to approve the adjournment of the Special Meeting to a later date or dates, if necessary or appropriate, including to solicit additional proxies to approve the proposal to adopt the Merger Agreement if there are insufficient votes to adopt the Merger Agreement at the time of the Special Meeting (the “Adjournment Proposal”). Parent and Merger Sub are owned by funds managed by affiliates of Clearlake Capital Group, L.P. (“Clearlake”), which is an investment firm operating integrated businesses across private equity, credit and other related strategies. Clearlake’s core sectors are technology, industrial and consumer. Pursuant to the terms of the Merger Agreement, Merger Sub will merge with and into Cornerstone, with Cornerstone continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the “Merger”).

If the Merger is completed, you will be entitled to receive $57.50 in cash, without interest thereon and less any applicable withholding taxes required by applicable law, for each share of Cornerstone common stock (“common stock”) that you own (unless you have properly exercised your appraisal rights), which represents a premium of approximately: (i) 31% to the closing price of Cornerstone’s common stock on June 1, 2021, the last full trading day prior to Clearlake filing a Schedule 13D in connection with Cornerstone’s potential strategic review process; and (ii) 40% to the 30-day volume weighted average price, ending on June 1, 2021, the last full trading day prior to Clearlake filing a Schedule 13D in connection with Cornerstone’s potential strategic review process.

The Company’s Board of Directors (the “Board of Directors”), after considering the factors more fully described in the enclosed proxy statement, has unanimously: (i) determined the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are advisable and fair to, and in the best interests of, Cornerstone and its stockholders; (ii) agreed that the Merger shall be governed by and effected in accordance with the General Corporation Law of the State of Delaware (the “DGCL”); (iii) declared it advisable to enter into the Merger Agreement and to consummate the transactions contemplated by the Merger Agreement, including the Merger; (iv) authorized and approved the execution, delivery and performance by Cornerstone of the Merger Agreement, and the consummation of the Merger and the transactions contemplated by the Merger Agreement; and (v) subject to the terms and conditions of the Merger Agreement, resolved to recommend, on behalf of Cornerstone, that the Cornerstone stockholders adopt the Merger Agreement and approve the Merger and the transactions contemplated thereby in accordance with the DGCL. The Board of Directors unanimously recommends, on behalf of Cornerstone that you vote: (1) “FOR” the adoption of the Merger Agreement; (2) “FOR” the approval, on an advisory (non-binding) basis, of the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

The enclosed proxy statement provides detailed information about the Special Meeting, the Merger Agreement and the Merger. A copy of the Merger Agreement is attached as Annex A to the proxy statement.

The proxy statement also describes the actions and determinations of the Board of Directors in connection with its evaluation of the Merger Agreement and the Merger. You should carefully read and consider the entire enclosed proxy statement and its annexes, including, but not limited to, the Merger Agreement, as they contain important information about, among other things, the Merger and how it affects you.

Whether or not you plan to attend the Special Meeting virtually, please sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card). If you attend the Special Meeting and vote virtually in person, your vote will revoke any proxy that you have previously submitted.

If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions.

Your vote is very important, regardless of the number of shares that you own. We cannot complete the Merger unless the proposal to adopt the Merger Agreement is approved by the affirmative vote of the holders of a majority of the shares of Cornerstone’s common stock that are issued and outstanding as of the close of business on August 24, 2021, which is the record date for the Special Meeting.

If you have any questions or need assistance voting your shares, please contact our proxy solicitor:

On behalf of the Board of Directors, I thank you for your support and appreciate your consideration of this matter.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the Merger, passed upon the merits or fairness of the Merger Agreement or the transactions contemplated thereby, including the proposed Merger, or passed upon the adequacy or accuracy of the information contained in the accompanying proxy statement. Any representation to the contrary is a criminal offense.

The accompanying proxy statement is dated September 10, 2021 and, together with the enclosed form of proxy card, is first being mailed on or about September 10, 2021.

Notice is hereby given that a virtual special meeting of stockholders (including any adjournments or postponements thereof, the “Special Meeting”) of Cornerstone OnDemand, Inc., a Delaware corporation (“Cornerstone” or the “Company”), to be held virtually on October 12, 2021, at 8:00 a.m. Pacific time at www.virtualshareholdermeeting.com/CSOD2021SM, for the following purposes:

Only stockholders of record as of the close of business on August 24, 2021, are entitled to notice of the Special Meeting and to vote at the Special Meeting or any adjournment, postponement or other delay thereof.

The Company’s Board of Directors (the “Board of Directors”) unanimously recommends, on behalf of Cornerstone, that you vote: (1) “FOR” the adoption of the Merger Agreement; (2) “FOR” the approval, on an advisory (non-binding) basis, of the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

All stockholders are invited to attend the Special Meeting virtually. Whether or not you plan to attend the Special Meeting virtually in person, please sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card). If you attend the Special Meeting and vote virtually in person, your vote will revoke any proxy that you have previously submitted. If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions.

This proxy statement is available on www.proxyvote.com. We intend to mail these proxy materials on or about September 10, 2021 to all stockholders of record entitled to vote at the special meeting.

A complete list of the stockholders entitled to vote at the Special Meeting will be available for examination during regular business hours for the 10 days prior to the Special Meeting at our headquarters, located at 1601 Cloverfield Blvd., Suite 620 South, Santa Monica, California 90404. Stockholders may examine the list for any legally valid purpose related to the Special Meeting. If you would like to examine the list, please contact our Secretary to schedule an appointment by calling (888) 365-2763 or writing to him at the address above. This list also will be available during the Special Meeting at www.virtualshareholdermeeting.com/CSOD2021SM.

WHETHER OR NOT YOU PLAN TO ATTEND THE SPECIAL MEETING VIRTUALLY IN PERSON, WE ENCOURAGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE: (1) BY TELEPHONE; (2) THROUGH THE INTERNET; OR (3) BY SIGNING AND DATING THE ENCLOSED PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. You may revoke your proxy or change your vote at any time before it is voted at the Special Meeting.

If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your broker or other agent cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions.

If you are a stockholder of record, voting virtually in person at the Special Meeting will revoke any proxy that you previously submitted. If you hold your shares through a bank, broker or other nominee, you must obtain a “legal proxy” in order to vote virtually in person at the Special Meeting.

If you fail to (1) return your proxy card, (2) grant your proxy electronically over the Internet or by telephone or (3) vote virtually in person at the Special Meeting, your shares will not be counted for purposes of determining whether a quorum is present at the Special Meeting and, if a quorum is present, will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement, but will have no effect on the Compensation Proposal or the Adjournment Proposal (as defined below).

You should carefully read and consider the entire accompanying proxy statement and its annexes, including, but not limited to, the Merger Agreement, along with all of the documents incorporated by reference into the accompanying proxy statement, as they contain important information about, among other things, the Merger and how it affects you. If you have any questions concerning the Merger Agreement, the Merger, the Special Meeting or the accompanying proxy statement, would like additional copies of the accompanying proxy statement or need help voting your shares of common stock, please contact our proxy solicitor:

The following questions and answers address some commonly asked questions regarding the Merger, the Merger Agreement and the Special Meeting. These questions and answers may not address all questions that are important to you. You should carefully read and consider the more detailed information contained elsewhere in this proxy statement and the annexes to this proxy statement, including, but not limited to, the Merger Agreement, along with all of the documents we refer to in this proxy statement, as they contain important information about, among other things, the Merger and how it affects you. You may obtain the information incorporated by reference in this proxy statement without charge by following the instructions under the caption, “Where You Can Find More Information.”

This proxy statement, and any documents to which Cornerstone refers to in this proxy statement, including all documents incorporated by reference in this proxy statement, as well as information included in oral statements or other written statements made or to be made by us, contains not only historical information, but also forward-looking statements, including all statements relating directly or indirectly to the timing or likelihood of completing the Merger, litigation and other information with respect to our plans and strategies, made pursuant to the safe-harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements represent Cornerstone’s current expectations or beliefs concerning future events, including but not limited to the expected completion and timing of the proposed transaction, expected benefits and costs of the proposed transaction, management plans and other information relating to the proposed transaction, strategies and objectives of Cornerstone for future operations and other information relating to the proposed transaction. Without limiting the foregoing, the words “believes,” “anticipates,” “plans,” “expects,” “intends,” “forecasts,” “should,” “estimates,” “contemplate,” “future,” “goal,” “potential,” “predict,” “project,” “projection,” “target,” “seek,” “may,” “will,” “could,” “should,” “would,” “assuming,” and similar expressions are intended to identify forward-looking statements. Stockholders are cautioned that any forward-looking statements are not guarantees of future performance and may involve significant risks and uncertainties, and that actual results may vary materially from those in the forward-looking statements. These risks and uncertainties include, but are not limited to, the risks detailed in our filings with the SEC, including in our most recent filings on Forms 10-K and 10-Q, factors and matters described or incorporated by reference in this proxy statement, and the following factors:

Consequently, all of the forward-looking statements that we make in this proxy statement are qualified by the information contained or incorporated by reference herein, including: (i) the information contained under this caption; and (ii) the information contained under the caption “Risk Factors,” and information in our consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the period ended December 31, 2020 and elsewhere in our most recent filings with the SEC, including our Quarterly Report on Form 10-Q for the quarter ended March 31, 2021, Quarterly Report on Form 10-Q for the quarter ended June 30, 2021 and any subsequent reports on Form 10-K, Form 10-Q or Form 8-K filed with the SEC from time to time and available at www.sec.gov . No assurance can be given that these are all of the factors that could cause actual results to vary materially from the forward-looking statements.

In addition, any forward-looking statements represent our estimates only as of the date they were made and should not be relied upon as representing our estimates as of any subsequent date. Except as required by applicable law, we undertake no obligation to publicly update forward-looking statements, whether as a result of new information, future events or otherwise. Stockholders are advised to consult any future disclosures that we make on related subjects as may be detailed in our other filings made from time to time with the SEC.

The enclosed proxy is solicited on behalf of the Board of Directors for use at the Special Meeting.

We will hold the Special Meeting virtually on October 12, 2021 at 8:00 a.m. Pacific time at www.virtualshareholdermeeting.com/CSOD2021SM and, if applicable, at any adjournment or postponement thereof.

At the Special Meeting, we will ask stockholders to vote on proposals to: (i) adopt the Merger Agreement; (ii) approve, on an advisory (non-binding) basis, the Compensation Proposal; and (iii) approve the Adjournment Proposal.

We do not expect that any matters other than the proposals set forth above will be brought before the Special Meeting, and only matters specified in the notice of the meeting may be acted upon at the Special Meeting.

Our stockholders must approve the proposal to adopt the Merger Agreement in order for the Merger to be consummated. If our stockholders fail to approve the proposal to adopt the Merger Agreement, the Merger will not be consummated. A copy of the Merger Agreement is attached as Annex A to this proxy statement, which we urge you to read carefully in its entirety.

Only stockholders of record as of the Record Date are entitled to notice of the Special Meeting and to vote at the Special Meeting. A list of stockholders entitled to vote at the Special Meeting will be available at our principal executive offices located at 1601 Cloverfield Blvd., Suite 620 South, Santa Monica, California 90404, during regular business hours for a period of no less than 10 days before the Special Meeting and will be available electronically at the Special Meeting.

The holders of a majority of the stock issued and outstanding and entitled to vote thereat, present virtually in person or represented by proxy, will constitute a quorum at the Special Meeting. As of the Record Date, there were 66,857,760 shares of common stock outstanding and entitled to vote at the Special Meeting, meaning that 33,428,881 shares of common stock must be represented virtually or by proxy at the Special Meeting to have a quorum. In the event that a quorum is not present at the Special Meeting, it is expected that the meeting will be adjourned to solicit additional proxies to approve the proposal to adopt the Merger Agreement.

The affirmative vote of the holders of a majority of the shares of common stock that are issued and outstanding as of the Record Date is required to adopt the Merger Agreement. As of the Record Date, 33,428,881 shares constitute a majority of the outstanding shares of common stock. Adoption of the Merger Agreement by stockholders is a condition to the Closing of the Merger.

Under our bylaws, the affirmative vote of the holders of a majority of the voting power of the shares present virtually in person or represented by proxy at the Special Meeting and entitled to vote on the subject matter is required to approve, on an advisory (non-binding) basis, the Compensation Proposal.

Approval of the Adjournment Proposal, whether or not a quorum is present, requires the affirmative vote of a majority of the voting power of the shares present virtually in person or represented by proxy at the Special Meeting and entitled to vote on the subject matter.

An abstention represents a stockholder’s affirmative choice to decline to vote on a proposal. If a stockholder abstains from voting, that abstention will have the same effect as if the stockholder voted “AGAINST” the proposal to adopt the Merger Agreement and “AGAINST” the proposal to approve, on an advisory (non-binding) basis, the Compensation Proposal. For stockholders who attend the virtual meeting or are represented by proxy and abstain from voting, the abstention will have the same effect as if the stockholder voted “AGAINST” any proposal to adjourn the Special Meeting to a later date or dates, if necessary or appropriate, to solicit additional

proxies to approve the proposal to adopt the Merger Agreement if there are insufficient votes to adopt the Merger Agreement at the time of the Special Meeting. As a result, an abstention of any of the aforementioned proposals will be counted for purposes of determining the presence or absence of a quorum and will also count as votes against such proposal.

Each “broker non-vote” will also count as a vote “AGAINST” the proposal to adopt the Merger Agreement, but will have no effect on the Compensation Proposal or any Adjournment Proposal. A “broker non-vote” generally occurs when a bank, broker or other nominee holding shares on your behalf does not vote on a proposal because the bank, broker or other nominee has not received your voting instructions and lacks discretionary power to vote the shares. “Broker non-votes,” if any, will be counted for the purpose of determining whether a quorum is present. However, because none of the proposals to be voted on at the Special Meeting are routine matters for which brokers may have discretionary authority to vote, Cornerstone does not expect any broker non-votes at the special meeting. As such, if you fail to instruct your broker, bank or other nominee how to vote your shares, your shares will not be counted towards a quorum at the Special Meeting.

As of the Record Date, our directors and executive officers beneficially owned and were entitled to vote, in the aggregate, 3,026,135 shares of common stock, representing approximately 4.5% of the shares of common stock outstanding on the Record Date (and approximately 7.5% of the shares of common stock outstanding when taking into account Cornerstone options and RSUs held, in the aggregate, by our directors and executive officers).

Our directors and executive officers have informed us that they currently intend to vote all of their respective shares of common stock (i) “FOR” the adoption of the Merger Agreement, (ii) “FOR” the approval, on an advisory (non-binding) basis, of the Compensation Proposal, and (iii) “FOR” the approval of the Adjournment Proposal.

If, at the close of business on the Record Date, your shares are registered in your name with our transfer agent, Computershare Trust Company, N.A., on the Record Date, you may cause your shares to be voted by returning a signed and dated proxy card in the accompanying prepaid envelope, or you may vote virtually in person at the Special Meeting. Additionally, you may grant a proxy electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card). You must have the enclosed proxy card available, and follow the instructions on the proxy card, in order to grant a proxy electronically over the Internet or by telephone. Based on your proxy cards or Internet and telephone proxies, the proxy holders will vote your shares according to your directions.

If you plan to attend the Special Meeting and wish to vote virtually in person, you will need to enter the 16-digit Control Number found next to the label “Control Number” on your proxy card voting instruction form, or in the email sending you the Proxy Statement. If you attend the Special Meeting, and vote virtually in person, your vote will revoke any previously submitted proxy. If your shares are registered in your name, you are encouraged to vote by proxy even if you plan to attend the Special Meeting virtually in person.

Voting instructions are included on your proxy card. All shares represented by properly signed and dated proxies received in time for the Special Meeting will be voted at the Special Meeting in accordance with the instructions of the stockholder. Properly signed and dated proxies that do not contain voting instructions will be voted:

(i) “FOR” the adoption of the Merger Agreement; (ii) “FOR” the approval, on an advisory (non-binding) basis, of the Compensation Proposal; and (iii) “FOR” the approval of the Adjournment Proposal.

If, at the close of business on the Record Date, your shares are held in “street name” through a bank, broker or other nominee, you may vote through your bank, broker or other nominee by completing and returning the voting form provided by your bank, broker or other nominee or attending the Special Meeting and voting virtually in person with a “legal proxy” from your bank, broker or other nominee. If such a service is provided, you may vote over the Internet or telephone through your bank, broker or other nominee by following the instructions on the voting form provided by your bank, broker or other nominee. If you do not return your bank’s, broker’s or other nominee’s voting form, do not vote via the Internet or telephone through your bank,

broker or other nominee, if possible, or do not attend the Special Meeting and vote virtually in person with a “legal proxy” from your bank, broker or other nominee, it will have the same effect as if you voted “AGAINST” the proposal to adopt the Merger Agreement but will not have any effect on the Compensation Proposal or the Adjournment Proposal.

If you are a stockholder of record entitled to vote at the Special Meeting, you may change your vote or revoke your proxy at any time before it is voted at the Special Meeting by:

If you have submitted a proxy, your virtual appearance at the Special Meeting will not have the effect of revoking your prior proxy; provided that you do not vote virtually in person or submit an additional proxy or revocation, which, in each case, will have the effect of revoking your proxy.

If you hold your shares of common stock in “street name,” you should contact your bank, broker or other nominee for instructions regarding how to change your vote. You may also vote virtually in person at the Special Meeting if you obtain a “legal proxy” from your bank, broker or other nominee.

Although it is not currently expected, the Special Meeting may be adjourned or recessed to a later date or dates, including for the purpose of soliciting additional proxies, if there are insufficient votes at the time of the Special Meeting to approve the proposal to adopt the Merger Agreement or if a quorum is not present at the Special Meeting. Other than an announcement to be made at the Special Meeting of the time, date and place of an adjourned meeting, an adjournment generally may be made without notice. Any adjournment or recess of the Special Meeting for the purpose of soliciting additional proxies will allow the stockholders who have already sent in their proxies to revoke them at any time prior to their use at the Special Meeting as adjourned or recessed.

The Board of Directors, after considering various factors described under the caption, “The Merger—Recommendation of the Board of Directors and Reasons for the Merger,” has unanimously: (i) determined the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are advisable and fair to, and in the best interests of, Cornerstone and its stockholders; (ii) agreed that the Merger shall be governed by and effected in accordance with the DGCL; (iii) declared it advisable to enter into the Merger Agreement and to consummate the transactions contemplated by the Merger Agreement, including the Merger; (iv) authorized and approved the execution, delivery and performance by Cornerstone of the Merger Agreement, and the consummation of the Merger and the transactions contemplated by the Merger Agreement; and (v) subject to the terms and conditions of the Merger Agreement, resolved to recommend, on behalf of Cornerstone, that the Cornerstone stockholders adopt the Merger Agreement and approve the Merger and the transactions contemplated thereby in accordance with the DGCL.

Accordingly, the Board of Directors unanimously recommends, on behalf of Cornerstone, that you vote: (i) “FOR” the adoption of the Merger Agreement; (ii) “FOR” the approval, on an advisory (non-binding) basis, of the Compensation Proposal; and (iii) “FOR” the approval of the Adjournment Proposal.

The expense of soliciting proxies will be borne by Cornerstone. We have retained MacKenzie Partners, Inc. (“MacKenzie”), a proxy solicitation firm, to solicit proxies in connection with the Special Meeting at a cost of approximately $25,000 plus expenses. We will also indemnify MacKenzie against losses arising out of its

provisions of these services on our behalf. In addition, we may reimburse banks, brokers and other nominees representing beneficial owners of shares for their expenses in forwarding soliciting materials to such beneficial owners. Proxies may also be solicited by our directors, officers and employees, personally or by telephone, email, fax, over the Internet or other means of communication. No additional compensation will be paid for such services.

Assuming timely satisfaction of necessary closing conditions, including the approval by stockholders of the proposal to adopt the Merger Agreement, we currently anticipate that the Merger will be consummated during the second half of 2021, although the Company cannot assure completion by any particular date, if at all. Since the Merger is subject to a number of conditions, the exact timing of the Merger cannot be determined at this time.

If the Merger is completed, the shares of Cornerstone’s common stock will be delisted from Nasdaq and deregistered under the Exchange Act, and shares of Cornerstone’s common stock will no longer be publicly traded. As such, Cornerstone will no longer file periodic reports with the SEC on account of Cornerstone’s common stock.

The proxy statement is available at investors.cornerstoneondemand.com and clicking on the link titled “Financials” and then “SEC Filings.”

If you have any questions concerning the Merger, the Special Meeting or the accompanying proxy statement, would like additional copies of the accompanying proxy statement or need help voting your shares of common stock, please contact our proxy solicitor:

This discussion of the Merger is qualified in its entirety by reference to the Merger Agreement, which is attached to this proxy statement as Annex A and incorporated into this proxy statement by reference. You should carefully read and consider the entire Merger Agreement, which is the legal document that governs the Merger, because this document contains important information about the Merger and how it affects you.

Cornerstone is a leading global provider of learning and people development solutions, delivered as software-as-a-service. Cornerstone’s common stock is listed on the Nasdaq under the symbol “CSOD”.

Parent is a Delaware corporation that was formed on July 27, 2021, solely for the purpose of engaging in the transactions contemplated by the Merger Agreement. Parent is owned by funds managed by affiliates of Clearlake and has not engaged in any business activities other than in connection with the transactions contemplated by the Merger Agreement and the related equity financing and debt financing transactions. Upon completion of the Merger, Cornerstone will be an indirect wholly owned subsidiary of Parent.

Merger Sub is a Delaware corporation and a wholly owned indirect subsidiary of Parent and was formed on July 27, 2021, solely for the purpose of engaging in the transactions contemplated by the Merger Agreement. Merger Sub has not engaged in any business activities other than in connection with the transactions contemplated by the Merger Agreement and the related equity financing and debt financing transactions. Upon the completion of the Merger, Merger Sub will cease to exist and Cornerstone will continue as the Surviving Corporation.

In connection with the transactions contemplated by the Merger Agreement, Parent and/or one of its affiliates has obtained equity and debt financing commitments for the transactions contemplated by the Merger Agreement. In addition, the Guarantors have delivered an Equity Commitment Letter to Parent, and the Guarantors and certain other investors have delivered a Preferred Equity Commitment Letter to Parent pursuant to which, upon the terms and subject to the conditions set forth in such letters, the investors have committed to capitalize Parent at the Closing of the Merger. For more information, please see the section of this proxy statement captioned “The Merger—Financing of the Merger.”

Upon the terms and subject to the conditions of the Merger Agreement, Merger Sub will merge with and into Cornerstone, with Cornerstone continuing as the Surviving Corporation. As a result of the Merger, Cornerstone will become an indirect wholly owned subsidiary of Parent, and our common stock will no longer be publicly traded and will be delisted from Nasdaq. In addition, our common stock will be deregistered under the Exchange Act, and we will no longer file periodic reports with the SEC. If the Merger is completed, you will not own any shares of the capital stock of the Surviving Corporation.

The Effective Time will occur upon the filing of a certificate of merger with the Secretary of State of the State of Delaware (or at such later time as we, Parent and Merger Sub may agree in writing and specify in the certificate of merger).

If the Merger Agreement is not adopted by Cornerstone stockholders, or if the Merger is not completed for any other reason:

At the Effective Time, each share of common stock (other than (A) shares held by Cornerstone (or held in Cornerstone’s treasury), (B) shares held by Parent or any other direct or indirect subsidiary of Parent or any assigns thereof, and (C) any Dissenting Shares) outstanding as of immediately prior to the Effective Time will be cancelled and automatically converted into the right to receive the Per Share Merger Consideration, without interest thereon and less any applicable withholding taxes required by applicable law.

After the Merger is completed, you will have the right to receive the Per Share Merger Consideration in respect of each share of common stock that you own (less any applicable withholding taxes required by applicable law), but you will no longer have any rights as a stockholder (except that stockholders who properly exercise their appraisal rights will have a right to receive payment of the “fair value” of their shares as determined pursuant to an appraisal proceeding, as contemplated by Delaware law). For more information, please see the section of this proxy statement captioned “—Appraisal Rights.”

The Board of Directors, together with Cornerstone management, regularly reviews and assesses Cornerstone’s performance, share price, risks, opportunities and strategy in light of the current business and economic environment, as well as evolving industry dynamics, as they, individually and together, may affect Cornerstone’s long-term strategic goals and plans. As a matter of practice, the Board of Directors and Cornerstone management, together with their professional advisors, regularly review and evaluate a wide range of strategic opportunities for business combinations, acquisitions and other financial and strategic alternatives for Cornerstone, including continuing as a standalone company, with a view to enhance stockholder value.

On February 2, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley LLP (“Cooley”), Cornerstone’s outside legal counsel. Representatives of Cornerstone management reviewed with the Board of Directors preliminary financial results with respect to Cornerstone’s operations through the end of fiscal year 2020. At the request of the Board of Directors, representatives of

Centerview then joined the meeting to review with the Board of Directors general market observations based on recent trends and Cornerstone’s financial performance relative to other companies in the software industry in order to inform the Board of Directors’ ongoing assessment of Cornerstone’s long-term strategic plan. The Board of Directors invited representatives of Centerview to join the meeting based on their experience and reputation in the software industry and their long-standing relationship with Cornerstone, including their work with Cornerstone in connection with the acquisition of Saba the prior year. Discussion ensued with respect to opportunities and challenges associated with executing on Cornerstone’s long-term strategic plan and other potential stockholder value enhancing opportunities, including potential financial and strategic partners for Cornerstone. The Board of Directors raised questions around whether the public markets would appropriately value Cornerstone’s ongoing execution of its long-term strategic plan. Following discussion, the Board of Directors determined to have further discussion on these topics at its next regularly scheduled meeting following the announcement on February 16, 2021 of results for the year and fiscal quarter ended December 31, 2020 and gauging associated investor and market reaction.

On March 15, 2021, in preparation for the next meeting of the Board of Directors and upon the recommendation of certain members of the Board of Directors, representatives of Cornerstone management met with representatives of Qatalyst Partners to obtain an additional viewpoint on Cornerstone’s financial and trading performance relative to certain peer groups and the market generally, analyst perceptions of Cornerstone, the software market environment, and potential financial and strategic partners for Cornerstone from a financial advisor considered by Cornerstone management to have significant experience with, and deep knowledge of, the software industry and its participants.

On March 17, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley and Centerview. Cornerstone management reviewed with the Board of Directors general investor sentiment following Cornerstone’s announcement of earnings for the fourth quarter ended December 31, 2020, Cornerstone’s historical stock price performance relative to certain peer groups and the market more generally, and Cornerstone management’s outlook (a) for the first quarter of 2021, which, based on current estimates, was expected to exceed publicly disclosed guidance, and (b) for full-year 2021, which remained in-line with Cornerstone’s then current internal forecasts. Representatives of Centerview reviewed reactions to Cornerstone’s results for the fourth quarter ended December 31, 2020 and management reviewed opportunities and challenges associated with executing on Cornerstone’s long-term standalone plan. Centerview noted that while software sector valuations remained at or near all-time highs and that strategic and financial buyers were aggressively pursuing high-growth assets, since the time of the last meeting of the Board of Directors on February 2, 2021 Nasdaq was down and it was possible that valuations and multiples could start to contract, which could lead to a decline in Cornerstone’s trading multiple and stock price. Centerview reviewed with the Board of Directors a framework for engagement with a select group of strategic and financial partners to gauge potential interest in Cornerstone, with the goal of such process to understand potential levels of interest with modest management time investment and using market feedback as the basis for fact-based decision making regarding strategic planning. The proposed framework included abbreviated management presentations to participants focusing on industry dynamics, the opportunities available to Cornerstone and forward-looking financial information. The Board of Directors discussed the positive macro market environment, including the historic multiples and premiums being paid in transactions in the software sector, the risk of a possible market downturn and the resulting negative pressure that would put on valuations, and the positives and negatives associated with undertaking a targeted outreach consistent with the framework previously discussed and determined that, despite the risk of leaks and internal management distractions, the additional market intelligence that might be obtained by such outreach would benefit the Board of Directors’ assessment of potential strategic alternatives, including pursuing Cornerstone’s long-term standalone plan. The Board of Directors discussed with Cornerstone management and representatives of Centerview the appropriate parties to contact in connection with such framework based on an assessment of the parties most likely to be interested in a potential transaction and able to provide an attractive valuation and determined to focus initially on a limited number of parties to limit the risk of leaks. It was also determined that the timing of such outreach should begin on an appropriate date following the announcement of Cornerstone’s first quarter earnings in May so that the contacted parties would have the benefit of the earnings release information that the Board of Directors then expected to be viewed favorably. Following the determination by the Board of Directors to proceed with the proposed framework, Cornerstone management recommended to the Board of Directors that Qatalyst Partners be engaged, together with Centerview, to act on behalf of Cornerstone in connection with such outreach based on Qatalyst Partners’

experience working with companies similarly situated to Cornerstone and the strength of its reputation and experience, specifically in the software sector. Based on, among other things, the recommendation of certain directors and the familiarity of other directors with Qatalyst Partners from prior professional interactions, the Board of Directors agreed and instructed Cornerstone management to work with Qatalyst Partners and Centerview to undertake such outreach following the announcement of earnings.

On May 6, 2021, Cornerstone announced results for its first quarter ended March 31, 2021.

On May 20, 2021, representatives of Qatalyst Partners sent Clearlake a proposed non-disclosure agreement. On June 2, 2021, after negotiations between the parties regarding the terms of the non-disclosure agreement, Clearlake and Cornerstone executed a non-disclosure agreement.

During the period beginning on May 18, 2021 and continuing until June 7, 2021, consistent with the discussions with the Board of Directors, representatives of Qatalyst Partners and Centerview contacted seven parties (including Clearlake, Party A, Party B and one possible strategic buyer, Party C, a portfolio company of a financial sponsor) regarding a potential strategic transaction. In addition, during that period, Cornerstone received unsolicited inbound requests from three financial sponsors (including Vector and Party D), regarding a potential strategic transaction. Of these parties (i) one party determined not to proceed in the process after initial contact and (ii) nine, including Clearlake, Vector, Party A, Party B, Party C and Party D, executed non-disclosure agreements with Cornerstone that included a “standstill” provision (but permitted parties to approach Cornerstone privately and confidentially during the standstill period), a fall-away provision (upon the entry or public announcement of certain acquisition transactions) and a restriction on engaging with any potential co-investor or financing source regarding a possible transaction with Cornerstone without Cornerstone’s approval, and participated in initial meetings with Cornerstone management. Of the nine parties that executed non-disclosure agreements, three parties determined not to proceed in the process after the management presentations and six parties, including Clearlake, Vector, Party A, Party B, Party C and Party D, were provided access following the management presentations to diligence information contained in a virtual data room established by Cornerstone.

After close of trading on June 1, 2021 (the “Unaffected Date”), Clearlake filed a Schedule 13D in connection with Cornerstone’s potential strategic review process, indicating beneficial ownership of approximately 8.3% of Cornerstone’s common stock.

On June 8, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview. Representatives of Qatalyst Partners and Centerview reviewed with the Board of Directors the parties included in discussions to date and noted that a majority of prospective buyers contacted had completed management presentations. Representatives of Qatalyst Partners and Centerview reviewed with the Board of Directors (i) historical stock price performance, (ii) Cornerstone’s stock price performance and trading volume following Clearlake’s filing of a Schedule 13D on June 1, 2021, including that on June 2, 2021, the closing price of Cornerstone common stock rose approximately 6.0% and daily trading volume was approximately 2.7x higher than the three month daily average trading volume prior to the Unaffected Date, (iii) Cornerstone’s trading in the context of selected peers, the broader software market and its Long Range Plan, (iv) potential next steps, including continued engagement with existing parties, coupled with additional outbound calls to other potential financial and strategic partners for Cornerstone, and request for parties to submit initial indications of interest (including with respect to value) in late June, and (v) the benefits and risks of contacting additional parties. Taking these facts into account, the Board of Directors discussed the advantages and disadvantages of engaging additional parties in discussions regarding a possible strategic transaction, including the additional third party valuation information that could be obtained and used to help guide strategic decision making and the incremental risk of leaks and management distraction. Representatives of Cornerstone management then reviewed with the Board of Directors the preliminary draft of the Long Range Plan including assumptions incorporated therein and, following discussion, the Board of Directors directed Cornerstone management to revisit certain expense assumptions in fiscal year 2022 to ensure that such assumptions were consistent with management’s current operational expectations for such fiscal year. Promptly following the meeting, in response to the input provided by the Board of Directors, Cornerstone management revised the Long Range Plan to reflect reduced operating expense assumptions for fiscal year 2022 for, among other things, reduced travel and consulting expenses, and the Board of Directors adopted the Long Range Plan as so revised by way of unanimous written consent on June 14, 2021. For a detailed discussion of the Long Range Plan, please see below under the caption “—Financial Projections”). The Board of Directors meeting continued in

executive session, during which the Board of Directors continued to discuss the positives and negatives of continuing, and potentially expanding, the strategic review process to include additional financial and strategic partners for Cornerstone. The Board determined to proceed with additional outreach, and authorized Cornerstone management to work with the financial advisors to target those parties believed most likely to be interested in and able to acquire Cornerstone. The Board of Directors determined to formally engage Qatalyst Partners and Centerview in connection with the ongoing strategic review process based on an assessment of such firms’ respective knowledge and deal experience in the software industry and strategic review processes and directed Cornerstone management to assist with the engagement process subject to Board of Directors’ approval of final engagement terms. On July 1, 2021, the Board of Directors approved the terms of engagement with each of Qatalyst Partners and Centerview, and Cornerstone executed an engagement letter with each of Qatalyst Partners and Centerview formalizing the engagement of each of Qatalyst Partners and Centerview to act as financial advisor to the Board of Directors in connection with a potential strategic transaction.

During the period beginning on June 9, 2021 and continuing until June 22, 2021, consistent with the discussions with the Board of Directors, representatives of Qatalyst Partners and Centerview discussed the potential transaction with an additional nine parties, including four possible strategic buyers and five possible financial sponsors. In addition, during that period, Cornerstone received unsolicited inbound requests from three financial sponsors, including Party E and Party F, regarding a potential strategic transaction. Of these parties, (i) nine parties determined not to proceed in the process after initial contact (which group included the four potential strategic buyers), (ii) three parties (including Party E and Party F) executed non-disclosure agreements with Cornerstone that included a “standstill” provision (but permitted parties to approach Cornerstone privately and confidentially during the standstill period), a fall-away provision (upon the entry or public announcement of certain acquisition transactions) and a restriction on engaging with any potential co-investor or financing source regarding a possible transaction with Cornerstone without Cornerstone’s approval, and participated in initial meetings with Cornerstone management, and (iii) following the initial management meetings, (x) one party determined not to proceed in the process and indicated to representatives of Qatalyst Partners and Centerview that it wanted to see future quarters of growth acceleration before considering an investment in Cornerstone, and (y) two parties, Party E and Party F, determined to proceed in the process and were provided access to diligence information contained in a virtual data room established by Cornerstone.

On June 22, 2021, representatives of Qatalyst Partners and Centerview sent process letters to each of the parties that remained active in the strategic process, including Clearlake, Vector, Party A, Party B, Party C, Party D, Party E, and Party F, requesting that such parties submit initial indications of interest to acquire Cornerstone, including the price per share proposed by such party, by June 28, 2021.

On June 23, 2021, Party C communicated to Philip S. Saunders, Cornerstone’s Chief Executive Officer, that it would not be submitting an indication of interest, having previously cited concerns around the amount of additional work, including with respect to integration, that Cornerstone still had to successfully complete before Party C would consider an acquisition of Cornerstone. Party C noted that its affiliated financial sponsor that had also been actively involved in Party C’s assessment of the opportunity may wish to separately continue in the process and that such financial sponsor would make such determination in the coming days. Mr. Saunders then relayed this communication to Qatalyst Partners and Centerview.

On June 24, 2021, representatives of Qatalyst Partners and Centerview received a proposal to acquire Cornerstone from Party B for a range of $50.00 to $55.00 per share in cash.

On June 24 and June 25, 2021, representatives of Qatalyst Partners communicated to each of the parties that had received the July 22 process letter, other than Party B that had already submitted a proposal, that they were participating in a highly competitive process and that the parties should be focused on providing a meaningful premium to the current stock price of Cornerstone in any indications of interest.

On June 25, 2021, representatives of each of Party A and the financial sponsor affiliated with Party C contacted representatives of Qatalyst Partners to inform Qatalyst Partners that such party would not be submitting an initial indication of interest. Party A noted that it was not going to participate in the process as it currently had other priorities and it believed there was substantial execution risk and work required to achieve Cornerstone’s transformation initiatives. The financial sponsor affiliated with Party C indicated that it was not going to proceed in the process given concerns around execution risk with Cornerstone’s long-term initiatives and that it did not believe its view of Cornerstone’s value would be competitive.

On June 28, 2021, representatives of Qatalyst Partners and Centerview received initial proposals to acquire Cornerstone from (i) Clearlake for $56.00 per share in cash, (ii) Vector for a range of $56.00 to $58.00 per share in cash, and (iii) Party E for $70.00 per share in cash. That same day, representatives of Party F informed representatives of Qatalyst Partners that Party F would not be proceeding with the process as Party F did not believe its view of Cornerstone’s value would be competitive.

On June 29, 2021, representatives of Party D contacted representatives of Qatalyst Partners and indicated that Party D would not be proceeding in the process as Party D did not believe its view of Cornerstone’s value would be competitive.

On June 30, 2021, representatives of Qatalyst Partners and Centerview called representatives of Party E to request more information regarding Party E’s $70.00 per share proposal and to inquire about potential financing sources for the transaction in light of the fact that publicly available historical transaction information indicated Party E had not previously led transactions of the size implied by their proposal. Party E indicated they were continuing to evaluate potential capital structure and sources.

On July 1, 2021, representatives of Qatalyst Partners called representatives of Party B regarding Party B’s proposal of $50.00 to $55.00 per share in cash and to inform Party B that such proposal was below other proposals provided and to give Party B the opportunity to increase its proposal. Party B told representatives of Qatalyst Partners that it would not be raising its proposal and that Party B would not be proceeding in the process.

On July 7, 2021, representatives of Party E called representatives of Qatalyst Partners and Centerview to discuss Party E’s proposal. Party E indicated to representatives of Qatalyst Partners and Centerview that due to resource and capacity constraints Party E was not in a position to acquire Cornerstone and withdrew its offer. However, Party E stated that it would be interested in participating as an equity partner for another potential acquiror should Cornerstone proceed with a strategic transaction.

Later that day, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview. Cornerstone management reviewed with the Board of Directors management’s preliminary estimates of certain performance metrics and trends through the end of the second quarter of 2021, including with respect to customer renewal rates, expense management, sales pipeline and employee turnover, and that, while successfully executing on the annual plan for fiscal year 2021 was still possible it remained subject to challenges in and outside of Cornerstone’s control. Following discussion, Cooley reviewed with the Board of Directors its fiduciary duties in connection with a strategic transaction process. Representatives of Qatalyst Partners and Centerview then provided an update to the Board of Directors on the status of the strategic process, including that Party A, Party B, Party C, as well as the financial sponsor of Party C, Party D, Party E and Party F had determined not to proceed, the reasoning provided by such parties, and the collective view by the financial advisors that Vector did not currently have sufficient funds under management to effectively lead an acquisition of Cornerstone, leaving Clearlake as the only remaining credible potential buyer. The financial advisors noted that they had conveyed to Vector their assessment regarding its ability to lead an acquisition, and in response Vector had requested the opportunity to invest with a qualified buyer, should Cornerstone proceed with a strategic transaction. Following discussion, representatives of Qatalyst Partners and Centerview reviewed certain financial aspects of the proposals submitted by Clearlake, Vector, Party B and Party E and discussed the potential benefits of introducing Vector to Clearlake, including as a way to potentially increase Clearlake’s view of Cornerstone’s value in light of the range included in Vector's earlier proposal. The Board of Directors discussed, among other things, the current state of the financial markets, valuations and multiples for software companies being at or near highs and the possibility of market contraction given future macro uncertainties, including the possible disruptive impact of COVID-19 and related variants (with regards to the return to work and day-to-day operations of Cornerstone and on the buying decisions of its customers), a dynamic interest rate environment and/or possible tax reform. The Board of Directors discussed the execution risk around the Long Range Plan and the fact that market perceptions of the degree of difficulty attendant to successfully executing on that plan may have kept other participants from staying actively involved in the strategic process and potentially has kept the price of Cornerstone’s common stock from improving despite the recent announcements by Cornerstone of otherwise positive trends in its business. Following discussion, the Board of Directors determined to (i) disclose to Vector Clearlake’s involvement in the process and permit Vector to communicate with Clearlake and (ii) permit the parties to proceed in the process so that they could complete confirmatory diligence and provide an increased and more definitive proposal for the Board of Directors to

consider, including with respect to legal and financial terms. Representatives of Cornerstone management reviewed with the Board of Directors the Internal Long Range Plan which supplemented the Long Range Plan to include non-public, unaudited prospective financial information for fiscal years 2025 and 2026 in order to provide the Board of Directors with a more detailed view of valuation and discussion ensued regarding certain of the assumptions incorporated into such plan. The Board of Directors requested additional time to review the Internal Long Range Plan and determined to continue discussion regarding the Internal Long Range Plan at the next meeting of the Board of Directors.

Later that day and following the meeting of the Board of Directors, representatives of Qatalyst Partners called representatives of Clearlake to suggest that Clearlake consider allowing Vector to participate in the proposed transaction. Clearlake represented that it would consider having Vector participate as a potential minority financing source in connection with a potential transaction.

On July 14, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley. Representatives of Cornerstone management reviewed with the Board of Directors the Internal Long Range Plan previously provided at the end of the last meeting of the Board of Directors and certain of the key assumptions on which the plan was prepared. For a detailed discussion of the Internal Long Range Plan, including such assumptions, please see below under the caption “—Financial Projections”). Discussion ensued and the Board of Directors adopted the Internal Long Range Plan and directed Cornerstone management to instruct each of Centerview and Qatalyst Partners, respectively, to use the Internal Long Range Plan in connection with providing financial analyses in connection with the Board of Directors’ evaluation of potential strategic alternatives, including the Merger. Representatives of Cornerstone management then provided an update to the Board of Directors on the status of the strategic process, including that Clearlake had confirmed that Clearlake had no objection to Vector participating in some of the confirmatory diligence sessions.

In addition, on July 14, 2021, representatives of Cornerstone management gave a presentation to representatives of Clearlake and Vector regarding Cornerstone’s business.

On July 15, 2021, representatives of Qatalyst Partners and Centerview, on behalf of Cornerstone, authorized Clearlake to initiate contact with certain identified preferred equity and debt financing sources in order to secure the necessary funding to finance the proposed transaction.

On July 19, 2021, representatives of Qatalyst Partners and Centerview sent a process letter to Clearlake requesting Clearlake submit its final proposal, including comments to the draft Merger Agreement to be provided in the virtual data room by no later than July 26, 2021.

Later that day, an auction draft of the Merger Agreement was provided to Clearlake via the virtual data room.

On July 23, 2021, a representative of a financial sponsor not involved in the process contacted Mr. Saunders, with whom such representative had a personal and professional relationship for a number of years, to discuss Cornerstone and inform Mr. Saunders that such representative had received inbound inquiries regarding Cornerstone. The financial sponsor representative indicated a general interest in Cornerstone, but did not request any information regarding, or express any interest in presently pursuing, a possible strategic transaction with Cornerstone. Given the late date of the process, that the financial sponsor expressed no current intent to actively engage Cornerstone regarding a possible strategic transaction and the belief of Cornerstone’s management and financial advisors that the financial sponsor was undifferentiated relative to the other participants in the process, no further action was taken.

On July 26, 2021, Clearlake submitted a revised proposal to acquire Cornerstone for $56.50 per share in cash, representing a 29.0% premium to the closing price per share of Cornerstone common stock on the Unaffected Date, the last full trading day prior to Clearlake filing a Schedule 13D, of $43.96 per share (the “Unaffected Cornerstone Stock Price”). The Clearlake proposal included a revised draft of the Merger Agreement, which proposed, among other things, a Company Termination Fee equal to 3.5% of the equity value of Cornerstone in certain limited circumstances, including in the event Cornerstone were to terminate the Merger Agreement in order to accept a superior offer from another party, and a Parent Termination Fee equal to 5.0% of the equity value of Cornerstone in certain limited circumstances, including if Clearlake failed to close the Merger when otherwise required by the Merger Agreement.

On July 27, 2021, representatives of Qatalyst Partners called representatives of Clearlake to convey that Clearlake’s revised $56.50 per share offer was too low and that Clearlake would need to raise its offer price in order to be successful in its bid to acquire Cornerstone.

On July 28, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview. Representatives of Qatalyst Partners and Centerview reviewed the strategic transaction process to date, including the fact that 24 parties (including five potential strategic buyers and 19 financial sponsors (including Clearlake)) had been contacted, and certain financial aspects of the revised $56.50 per share proposal from Clearlake. The Board of Directors discussed the current state of the financial markets, including the possibility of a market correction, and the substantial execution challenges facing Cornerstone previously assessed in prior meetings. Additionally, representatives of Qatalyst Partners and Centerview discussed with the Board of Directors the possibility that additional opportunities to initiate a strategic process in the short term would be challenging given that Cornerstone would likely need to execute on its current strategic plan to garner renewed attention from potential financial and strategic partners. The Board of Directors meeting continued in executive session, during which the Board of Directors discussed certain key areas of the business, including that near term catalysts for growth were limited given that Cornerstone’s current leverage ratio made it difficult for Cornerstone to meaningfully participate as an active acquiror while competitors with more ready access to capital could seek to capture consolidation opportunities that may make the competitive landscape more difficult for Cornerstone. Following discussion, the Board of Directors determined that the valuation reflected in Clearlake’s current proposal was low, but that there may be a path to completing a transaction if Clearlake were to increase its proposal and increase the reverse termination fee payable by Clearlake, thereby increasing in the view of the Board of Directors the level of closing certainty. Following the meeting, a representative of the Board of Directors contacted representatives of Qatalyst Partners to relay the Board of Directors decision and to instruct Qatalyst Partners to convey the same to Clearlake.

On July 30, 2021, Cooley provided a revised draft of the Merger Agreement to Sidley Austin LLP (“Sidley”), Clearlake’s outside legal counsel, which draft proposed, among other things, a 3.0% Company Termination Fee and 8.0% Parent Termination Fee, and an initial draft of the Miller Support Agreement, pursuant to which, among other things, Mr. Miller and certain stockholders of Cornerstone affiliated with Mr. Miller would be required to vote their shares of common stock in favor of the adoption of the Merger Agreement and approval of the Merger and the other transactions contemplated by the Merger Agreement and against any alternative acquisition proposals and any action which is intended, or would reasonably be expected, to impede, interfere with, delay, postpone, discourage or adversely affect the Merger. That same day, Sidley provided to Cooley initial drafts of the Equity Commitment Letter and Limited Guarantee and initial drafts of the Silver Lake Support Agreements pursuant to which, among other things, the Silver Lake Group would be required to support certain amendments to the Indenture governing the Cornerstone Convertible Notes to facilitate the consummation of the proposed Merger and the financing relating thereto.

Also on July 30, 2020, Qatalyst Partners informed Clearlake that the Board of Directors would not transact at Clearlake’s current proposal.

On July 31, 2021, Sidley provided a revised draft of the Merger Agreement to Cooley, which draft proposed, among other things, a 3.5% Company Termination Fee and 6.0% Parent Termination Fee. That same day, Sidley sent to Cooley initial drafts of the Preferred Equity Commitment Letter and the Debt Commitment Letter.

On August 2, 2021, Clearlake submitted a revised proposal to acquire Cornerstone for $57.00 per share in cash, representing a 30.0% premium to the Unaffected Cornerstone Stock Price. Clearlake’s revised proposal included executed debt financing commitments representing the proposed debt financing for the transaction as well as executed equity financing commitments representing the proposed equity financing for the transaction.

Later that same day, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview. Representatives of Qatalyst Partners and Centerview provided an update on the status of discussions with Clearlake, including the revised proposal of $57.00 per share, and reviewed with the Board of Directors certain aspects of the proposed equity and debt financing package submitted by Clearlake, including the sources and uses provided by Clearlake. The Board of Directors

meeting continued in executive session, during which the Board of Directors further discussed Clearlake’s revised proposal and possible responses. Following discussion, the Board of Directors determined to continue to negotiate price and instructed representatives of Qatalyst Partners and Centerview to seek a higher price from Clearlake.

Later that same day, Cooley provided a revised draft of the Merger Agreement to Sidley, which draft proposed, among other things, a 3.0% Company Termination Fee and 7.5% Parent Termination Fee.

On August 3, 2021, Qatalyst Partners called representatives of Clearlake to discuss the status of the proposed transaction and conveyed that there was a path for Cornerstone to transact at $58.00 per share with a 3.25% Company Termination Fee and a 7.0% Parent Termination Fee. Clearlake stated that it could not support a bid at $58.00 per share and responded with a revised proposal to acquire Cornerstone for $57.50 per share in cash, representing a 31.0% premium to the Unaffected Cornerstone Stock Price, indicating that it would not raise its price any further.

Later that same day, Sidley provided a revised draft of the Merger Agreement to Cooley, which draft proposed, among other things, a 3.5% Company Termination Fee and 6.0% Parent Termination Fee, and an initial draft of the Clearlake Support Agreement with the Clearlake Stockholder pursuant to which, among other things, the Clearlake Stockholder would be required to vote its shares of common stock in favor of the adoption of the Merger Agreement and the approval of the Merger and the other transactions contemplated by the Merger Agreement and against any alternative acquisition proposals and any action which is intended, or would reasonably be expected, to impede, interfere with, delay, postpone, discourage or adversely affect the Merger.

Later that same day, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview. Representatives of Cornerstone management reviewed with the Board of Directors certain adjustments proposed by Cornerstone management to fiscal year 2021 of the Internal Long Range Plan, including to reflect actual results through the end of the second quarter and the estimated cost reductions for 2021. It was noted that because of the one-time nature of the cost reductions, they did not impact any fiscal year in the Internal Long Range Plan other than 2021. Following discussion, the Board of Directors directed Cornerstone management to revise the Internal Long Range Plan to reflect such adjustments and to provide such adjustments to Clearlake. For a detailed discussion of the Adjusted Internal Long Range Plan, including such adjustments, please see below under the caption “—Financial Projections”. Representatives of Qatalyst Partners and Centerview provided an update on the status of discussions with Clearlake including the revised proposal of $57.50 per share provided by Clearlake and its statement that it would not increase price any further. Representatives of Cooley described certain material terms and proposed changes to the draft Merger Agreement, including (a) the increase of the Company Termination Fee from 3.0% to 3.5% of equity value and the decrease of the Parent Termination Fee from 7.5% to 6.0% of equity value, and (b) the requirement that the marketing period for Parent’s debt financing not begin until US HSR Act and stockholder approval had been obtained. The Board of Directors meeting continued in executive session, during which the Board of Directors further discussed Clearlake’s $57.50 per share proposal. Representatives of Cooley then described the preliminary calculations that had been conducted in connection with the excise tax potentially payable by certain members of Cornerstone management as a result of the anticipated transaction under Internal Revenue Code Section 4999 and the concept of gross-up payments for any related taxes payable with respect to the payments of such excise taxes (such arrangements, “280G gross-up arrangements”). After discussion and review of the preliminary excise tax and gross-up estimates, including that Clearlake would likely not agree to any proposal that did not limit the potential liability associated with 280G gross-up arrangements, the Board of Directors determined to provide 280G gross-up arrangements for affected members of Cornerstone management subject to a $7,000,000 aggregate cap. After discussion, the Board of Directors concluded that, in light of all the factors and risks associated with Cornerstone’s standalone plan, concerns regarding the risk of losing Clearlake’s final offer of $57.50 per share if Cornerstone continued to pursue a higher price, the unlikeness of there being another acquiror willing to pay a higher price to acquire Cornerstone given the broad nature of the strategic process conducted and the fact the Clearlake’s proposal enabled Cornerstone stockholders to realize an immediate, certain and significant premium for their stock without the execution and other risks associated with Cornerstone’s standalone plan, it would agree to move forward on the basis of the $57.50 per share proposal provided that Clearlake agree to (i) the marketing period beginning after Labor Day and (ii) a

3.25% Company Termination Fee and 7.0% Parent Termination Fee. In addition, the Board determined it would seek from Clearlake the proposed 280G gross-up arrangements subject to a $7,000,000 aggregate cap. Following the meeting, the Board of Directors directed representatives of Qatalyst Partners to relay the Board of Directors’ decision to Clearlake.

Later that same day, at the direction of the Board of Directors, a representative of Qatalyst Partners called a representative of Clearlake to express the Board of Directors’ willingness to proceed on the basis of the last offer proposed by Clearlake of $57.50 per share in cash if Clearlake agreed to the terms outlined by the Board of Directors. Shortly thereafter, Cooley sent a revised draft of the Merger Agreement to Sidley reflecting the terms outlined by the Board of Directors.

On August 4, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview. Representatives of Cornerstone management provided an update to the Board of Directors regarding the current transaction status and noted that the terms of the Silver Lake Support Agreements had not yet been finalized. Following the update from Cornerstone management, representatives of Qatalyst Partners reviewed with the Board of Directors Qatalyst Partners’ financial analyses of Clearlake’s $57.50 per share proposal and then representatives of Centerview reviewed with the Board of Directors Centerview’s financial analyses of Clearlake’s $57.50 per share proposal. Following the presentations by Qatalyst Partners and Centerview, Cooley reviewed with the Board of Directors its fiduciary duties applicable in connection with the strategic transaction process and the proposed Merger, and reviewed certain material terms of the draft Merger Agreement and related transactions, including (a) that the marketing period for Parent’s debt financing would begin on the earlier of September 8, 2021 and the first date following the filing of the definitive proxy, which date was anticipated to roughly coincide with September 8, 2021 absent SEC review of the preliminary proxy, (b) that Clearlake had agreed to the 3.25% Company Termination Fee and 7.0% Parent Termination Fee, (c) the conditions to the consummation of the Merger, (d) that Mr. Miller (together with certain stockholders affiliated with Mr. Miller), the Clearlake Stockholder and the Silver Lake Group would be entering into certain support agreements concurrently with the execution of the Merger Agreement, and (e) that Clearlake had agreed to the proposed 280G gross-up arrangements subject to the $7,000,000 aggregate cap proposed by Cornerstone. Cooley noted to the Board of Directors that Clearlake indicated it had not included in a Support Agreement from Vector its latest proposal because it was unclear whether Vector would ultimately be included as a minority investor in the proposed transaction. The Board of Directors then adjourned the meeting and determined to reconvene the meeting after the terms and conditions to the Silver Lake Support Agreements were finalized as among the parties.

Throughout the remainder of August 4 and 5, 2021, the parties worked to finalize the Merger Agreement and the support agreements, including a support agreement from Vector (which would be entered into in connection with Clearlake agreeing that Vector could make a minority investment in Parent at the closing of the Merger). The parties also worked to finalize the Debt Commitment Letters, the Preferred Equity Commitment Letter, the Equity Commitment Letter and the Limited Guarantee.

On the afternoon of August 5, 2021, the Board of Directors held a meeting with Cornerstone management and representatives of Cooley, Qatalyst Partners and Centerview to review the final Clearlake $57.50 per share proposal. Representatives of Qatalyst Partners confirmed to the Board of Directors that there were no material changes to the financial analysis presented to the Board of Directors by Qatalyst Partners at the meeting of the Board of Directors the day prior and delivered to the Board of Directors the oral opinion of Qatalyst Partners, which was subsequently confirmed by delivery of a written opinion dated August 5, 2021, to the effect that, as of that date and based on and subject to various assumptions, qualifications, limitations and other matters set forth in its written opinion, the $57.50 per share in cash to be received by the holders of shares of common stock (other than Parent or any affiliate thereof) pursuant to, and in accordance with, the Merger Agreement was fair, from a financial point of view, to such holders, as more fully described below in the section entitled “—Opinion of Qatalyst Partners LP.” Representatives of Centerview then confirmed to the Board of Directors that there were no material changes to the financial analysis presented by Centerview to the Board of Directors at the meeting of the Board of Directors from the day prior and delivered to the Board of Directors the oral opinion of Centerview, which was subsequently confirmed by delivery of a written opinion dated such date that, as of such date and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations set forth in its written opinion, the $57.50 per share in cash to be paid to the holders of shares of common stock (other than Excluded Shares) pursuant to, and in accordance with, the Merger

Agreement was fair, from a financial point of view, to such holders. For a detailed discussion of Centerview’s opinion, please see below under the caption “—Opinion of Centerview Partners LLC”). Following the presentations by Qatalyst Partners and Centerview, Cooley reviewed with the Board of Directors the material terms of the draft Merger Agreement and related transactions, including the related transaction documents. The Board of Directors then discussed the potential transaction with Clearlake, and, after carefully considering the matters discussed during that meeting and prior meetings of the Board of Directors (for more information, see the section titled “ —Reasons for the Merger”), the Board of Directors unanimously (i) determined that the Merger Agreement, the Voting and Support Agreements and the other transactions contemplated by the Merger Agreement, including the Merger (the “Transactions”), are advisable and fair to, and in the best interests of, Cornerstone and its stockholders; (ii) agreed that the Merger shall be governed and effected in accordance with the DGCL; (iii) declared it advisable to enter into the Merger Agreement, the Voting and Support Agreements and to consummate the Transactions, (iv) authorized and approved the execution, delivery and performance by Cornerstone of the Merger Agreement, and the consummation of the Transactions; and (v) subject to the terms and conditions of the Merger Agreement, resolved to recommend that the Cornerstone stockholders, on behalf of Cornerstone, to adopt the Merger Agreement and approve the Merger and the transactions contemplated thereby in accordance with the DGCL.

Later that day, the parties executed the Merger Agreement, the Voting and Support Agreements, the Equity Commitment Letter, the Limited Guarantee, the Preferred Equity Commitment Letter and the Debt Commitment Letter, and Cornerstone and Clearlake issued a joint press release announcing the transaction, including that Vector had agreed to make a minority investment in Parent at the Closing of the Merger (which was subsequently disclosed in an amended Schedule 13D filed by Clearlake to consist of a contribution of shares of common stock of Cornerstone and cash for an aggregate value of approximately $100 million).

On August 9, 2021, Party E contacted Cornerstone to request, and received, permission under the terms of Party E’s non-disclosure agreement with Cornerstone to engage with Clearlake regarding a potential equity co-investment in Parent.

On August 19, 2021, each of Cornerstone and Parent filed its Premerger Notification and Report Form with the FTC and the Antitrust Division for review in connection with the Merger.

The Board of Directors has unanimously: (i) determined the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are advisable and fair to, and in the best interests of, Cornerstone and its stockholders; (ii) agreed that the Merger shall be governed and effected in accordance with the DGCL; (iii) declared it advisable to enter into the Merger Agreement and to consummate the transactions contemplated by the Merger Agreement, including the Merger; (iv) authorized and approved the execution, delivery and performance by Cornerstone of the Merger Agreement, and the consummation of the Merger and the transactions contemplated by the Merger Agreement; and (v) subject to the terms and conditions of the Merger Agreement, resolved to recommend that, on behalf of Cornerstone, the Cornerstone stockholders adopt the Merger Agreement and approve the Merger and the transactions contemplated thereby in accordance with the DGCL.

The Board of Directors unanimously recommends, on behalf of Cornerstone, that you vote: (i) “FOR” the adoption the Merger Agreement; (ii) “FOR” the approval, on an advisory (non-binding) basis, of the Compensation Proposal; and (iii) “FOR” the approval of the Adjournment Proposal.

In the course of reaching its determination and recommendation, the Board of Directors consulted with Cornerstone management, Cooley and its financial advisors, Qatalyst Partners and Centerview. The Board of Directors considered the following reasons (which are not listed in any relative order of importance), all of which it viewed as generally supporting its (i) determination that the Merger Agreement and the other transactions contemplated by the Merger Agreement, the Voting and Support Agreements and the Transactions, are advisable and fair to, and in the best interest of, Cornerstone and its stockholders, (ii) authorization and approval of the execution, delivery and performance by Cornerstone of the Merger Agreement and the consummation of the

Transactions, including the Merger and (iii) subject to the terms and conditions of the Merger Agreement, recommendation that Cornerstone stockholders adopt the Merger Agreement and approve the Merger and the Transactions.

The Board of Directors also considered a number of uncertainties and risks concerning the Merger, including the following (which are not necessarily presented in order of relative importance):

The foregoing discussion of reasons for the recommendation to adopt the Merger Agreement and approve the Merger and the transactions contemplated thereby addresses the reasons considered by Cornerstone’s Board of Directors in consideration of its recommendation. In view of the wide variety of reasons considered by the Board of Directors in connection with its evaluation of the Merger and the complexity of these matters, the Board of Directors did not find it practicable to, and did not, quantify or otherwise assign relative weights to the

specific reasons considered in reaching its determination and recommendation. Rather, in considering the information and reasons described above, individual members of the Board of Directors each applied his or her own personal business judgment to the process and may have given differing weights to differing factors. The Board of Directors based its unanimous recommendation on the totality of the information presented. The explanation of the reasons and reasoning set forth above contain forward-looking statements that should be read in conjunction with the section of this proxy statement entitled “Forward-Looking Statements.”

While Cornerstone has publicly issued limited short-term guidance concerning aspects of its expected financial performance from time to time, Cornerstone does not, as a matter of course, publicly disclose forecasts or internal projections as to future performance or results of operations due to the inherent unpredictability of the underlying assumptions and projections. However, in connection with the review of potential strategic alternatives, including Cornerstone’s evaluation of the Merger, Cornerstone’s management, at the direction of the Board of Directors, prepared certain unaudited, long-range financial projections (collectively, as described and defined in more detail below, the “Projections”). Cornerstone management provided the Projections to the Board of Directors, and at the direction of the Board of Directors, to Qatalyst Partners and Centerview. The Board of Directors directed each of Qatalyst Partners and Centerview, respectively, to use the Projections as they existed at the applicable time in connection with providing financial analyses in connection with the evaluation by the Board of Directors of potential strategic alternatives, including the Merger.

In June 2021, management prepared non-public, unaudited prospective financial information for fiscal years 2021 through 2024 (the “Long Range Plan”), and the Long Range Plan was discussed with, and approved for use by, the Board of Directors in connection with the evaluation of potential strategic alternatives, including the Merger. The Long Range Plan was provided to Qatalyst Partners and Centerview as well as Clearlake and other potential acquirers in late-June 2021. In July 2021, management supplemented the Long Range Plan to include non-public, unaudited prospective financial information for fiscal years 2025 and 2026 (the “Internal Long Range Plan”), and provided the Internal Long Range Plan to the Board of Directors and to Qatalyst Partners and Centerview. The Internal Long Range Plan was not provided to any potential acquirers.

Later in July 2021, management made adjustments to the unaudited forecasts for fiscal year 2021 (such revisions, the “Long Range Plan Adjustments”) to, among other things, reflect actual results through the second quarter of 2021 and reduced cost estimates for the second half of fiscal year 2021 due, in part, to lighter than expected travel and entertainment expenses, delays in relation to certain hiring objectives and reductions to discretionary expense reserves in the annual budget, and at the direction of the Board of Directors, provided the Long Range Plan Adjustments to Qatalyst Partners and Centerview. As compared to the Long Range Plan, the Long Range Plan Adjustments reflected an increase in total revenue for fiscal year 2021 from to $855 million to $859 million, an increase in adjusted earnings before interest, taxes, depreciation and amortization (“EBITDA”) from $276 million to $304 million, an increase in non-GAAP operating income from $226 million to $255 million, an increase in levered free cash flow from $173 million to $185 million and an increase in unlevered free cash flow from $221 million to $235 million. Because of the one-time nature of the cost reductions included in the Long Range Plan Adjustments, and such reductions did not impact any fiscal year other than 2021. The Long Range Plan Adjustments (except for adjusted EBITDA and levered free cash flow, separate line items for which were not included in the Long Range Plan previously shared with Clearlake) were shared with Clearlake on August 3, 2021 in connection with Clearlake’s due diligence review. The Internal Long Range Plan was revised to reflect the Long Range Plan Adjustments (as so revised, the “Adjusted Internal Long Range Plan”), and at the direction of the Board of Directors, provided to Qatalyst Partners and Centerview for purposes of rendering their respective fairness opinions to the Board of Directors and related financial analyses.

The Projections were not prepared with a view toward public disclosure or toward complying with GAAP, nor were they prepared with a view toward compliance with the published guidelines of the SEC, or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of projections of prospective financial information. The non-GAAP financial measures used in the Projections were relied upon by the Board of Directors in connection with its consideration of the Merger and the Merger Consideration. While Cornerstone believes that such non-GAAP financial measures provide useful supplemental information in analyzing Cornerstone’s financial results, there are limitations associated with the use of such financial measures. Such non-GAAP measures as used by Cornerstone may not be directly comparable to similarly titled measures used by other companies and should not be considered in isolation from, or as a

substitute for, financial information presented in accordance with GAAP. The SEC rules, which otherwise would require a reconciliation of a non-GAAP financial measure to a GAAP financial measure, do not apply to non-GAAP financial measures provided to a board of directors or financial advisors in connection with a proposed business combination transaction such as the proposed Transactions if the disclosure is included in a document such as this proxy statement. In addition, reconciliations of non-GAAP financial measures to a GAAP financial measure were not provided to or relied upon by the Board of Directors or Cornerstone’s financial advisors in connection with the Merger. Accordingly, Cornerstone has not provided a reconciliation of the financial measures included in the Projections to the relevant GAAP financial measures. The Projections may differ from published analyst estimates and forecasts, and do not take into account any events or circumstances after the date they were prepared, including the announcement of the Transactions.

The Projections reflect estimates and assumptions made by Cornerstone management with respect to general business, economic, competitive, regulatory and other market and financial conditions and other future events, all of which are difficult to predict and many of which are beyond Cornerstone’s control. In particular, the Projections, while presented with numerical specificity, necessarily were based on numerous variables and assumptions (as described below) that are inherently uncertain. Because the Projections cover multiple years, by their nature, they become subject to greater uncertainty with each successive year and are unlikely to anticipate each circumstance that will have an effect on Cornerstone’s business and its results of operations. None of Cornerstone, Parent or any of their respective affiliates, advisors or other representatives makes any representation to any stockholder regarding the validity, reasonableness, accuracy or completeness of the Projections or the ultimate performance of Cornerstone relative to the financial projections. The inclusion of the Projections in this proxy statement does not constitute an admission or representation of Cornerstone that the Projections or the information contained therein is material. Except as required by applicable law, neither Cornerstone nor any of its affiliates intends to, and each of them disclaims any obligation to, update, correct or otherwise revise the Projections if any or all of them have changed or change or otherwise have become, are or become inappropriate (even in the short term). These considerations should be taken into account if evaluating the Projections, which were prepared as of an earlier date.

The Projections should be evaluated, if at all, in conjunction with the historical financial statements and other information regarding Cornerstone in its public filings with the SEC. The Projections were developed by Cornerstone management on a standalone basis without giving effect to the Merger and the other transactions contemplated by the Merger Agreement, and therefore the Projections do not give effect to the proposed Transactions or any changes to Cornerstone’s operations or strategy that may be implemented after the consummation of the Merger, including any costs incurred in connection with the proposed Transactions. Furthermore, the Projections do not take into account the effect of any failure of the proposed Transactions to be completed and should not be viewed as accurate or continuing in that context.

The Projections further reflect subjective judgment in many respects and, therefore, are susceptible to multiple interpretations and periodic revisions based on actual experience and business developments. The inclusion of the Projections should not be regarded as an indication that Cornerstone or anyone who received the Projections then considered, or now considers, the Projections to be necessarily predictive of actual future events, and this information should not be relied upon as such. Cornerstone management views the Projections as being subject to inherent risks and uncertainties associated with such long-range projections.

Adjusted EBITDA, non-GAAP operating income, levered free cash flow and unlevered free cash flow contained in the Projections set forth below are each “non-GAAP financial measures,” which are financial performance measures that are not calculated in accordance with GAAP. These non-GAAP financial measures should not be viewed as a substitute for GAAP financial measures and may be different from non-GAAP financial measures used by other companies. Furthermore, there are limitations inherent in non-GAAP financial measures because they exclude charges and credits that are required to be included in a GAAP presentation. Accordingly, these non-GAAP financial measures should be considered together with, and not as an alternative to, financial measures prepared in accordance with GAAP.

The information and table set forth below is included solely to give Cornerstone stockholders access to certain of the financial projections that were made available to the Board of Directors, Qatalyst Partners and Centerview and is not included in this proxy statement in order to influence any stockholder’s decision to vote with respect to the adoption of the Merger Agreement or for any other purpose:

Cornerstone retained Qatalyst Partners to act as financial advisor to our Board of Directors in connection with a potential transaction such as the Merger and to evaluate whether the Merger Consideration to be received pursuant to, and in accordance with, the terms of the Merger Agreement by the holders of shares of Cornerstone common stock (other than Parent or any affiliate of Parent), was fair, from a financial point of view, to such holders. Cornerstone selected Qatalyst Partners to act as Cornerstone’s financial advisor based on Qatalyst Partners’ qualifications, expertise, reputation, and knowledge of Cornerstone’s business and the industry in which Cornerstone operates. Qatalyst Partners has provided its written consent to the reproduction of its opinion in this proxy statement. At the meeting of our Board of Directors on August 5, 2021, Qatalyst Partners rendered to our Board of Directors its oral opinion, subsequently confirmed in writing, to the effect that, as of August 5, 2021, and based upon and subject to the various assumptions, qualifications, limitations and other matters set forth therein, the Merger Consideration to be received pursuant to, and in accordance with, the terms of the Merger Agreement by the holders of shares of Cornerstone common stock (other than Parent or any affiliate of Parent), was fair, from a financial point of view, to such holders. Following the meeting, Qatalyst Partners delivered its written opinion, dated August 5, 2021, to our Board of Directors.

The full text of the opinion of Qatalyst Partners, dated as of August 5, 2021, is attached to this proxy statement as Annex B and is incorporated into this proxy statement by reference. The opinion sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations and qualifications of the review undertaken by Qatalyst Partners in rendering its opinion. You should read the opinion carefully in its entirety. Qatalyst Partners’ opinion was provided to our Board of Directors and addresses only, as of the date of the opinion, the fairness, from a financial point of view, of the Merger Consideration to be received pursuant to, and in accordance with, the terms of the Merger Agreement by the holders of shares of Cornerstone common stock (other than Parent or any affiliate of Parent), to such holders, and it does not address any other aspect of the Merger. It does not constitute a recommendation to any Cornerstone stockholder as to how to vote with respect to the Merger or any other matter and does not in any manner address the price at which the shares of Cornerstone common stock will trade at any time. The summary of Qatalyst Partners’ opinion set forth herein is qualified in its entirety by reference to the full text of the opinion, which is attached to this proxy statement as Annex B.

For purposes of its opinion, Qatalyst Partners reviewed the Merger Agreement, certain related documents and certain publicly available financial statements and other business and financial information of Cornerstone.

Qatalyst Partners also reviewed certain forward-looking information relating to Cornerstone prepared by management of Cornerstone, including the Adjusted Internal Long Range Plan. Additionally, Qatalyst Partners discussed the past and current operations and financial condition and the prospects of Cornerstone with senior management of Cornerstone. Qatalyst Partners also reviewed the historical market prices and trading activity for Cornerstone common stock and compared the financial performance of Cornerstone and the prices and trading activity of Cornerstone common stock with that of certain other selected publicly-traded companies and their securities. In addition, Qatalyst Partners reviewed the financial terms, to the extent publicly available, of selected acquisition transactions and performed such other analyses, reviewed such other information and considered such other factors as it deemed appropriate.

In arriving at its opinion, Qatalyst Partners assumed and relied upon, without independent verification, the accuracy and completeness of the information that was publicly available or supplied or otherwise made available to, or discussed with, Qatalyst Partners by Cornerstone. With respect to the Adjusted Internal Long Range Plan, Qatalyst Partners was advised by Cornerstone’s management, and Qatalyst Partners assumed, that the Adjusted Internal Long Range Plan had been reasonably prepared on a basis reflecting the best currently available estimates and judgments of the management of Cornerstone of the future financial performance of Cornerstone and other matters covered thereby. Qatalyst Partners assumed that the Merger will be consummated in accordance with the terms set forth in the Merger Agreement, without any modification, waiver or delay. In addition, Qatalyst Partners assumed that in connection with the receipt of all the necessary approvals of the proposed Merger, no delays, limitations, conditions or restrictions will be imposed that could have an adverse effect on Cornerstone or the contemplated benefits expected to be derived in the proposed Merger. Qatalyst Partners did not make any independent evaluation or appraisal of the assets or liabilities (contingent or otherwise) of Cornerstone or its affiliates, nor was Qatalyst Partners furnished with any such evaluation or appraisal. In addition, Qatalyst Partners relied, without independent verification, upon the assessment of the management of Cornerstone as to the existing and future technology and products of Cornerstone and the risks associated with such technology and products. Qatalyst Partners’ opinion has been approved by Qatalyst Partners’ opinion committee in accordance with its customary practice. Qatalyst Partners’ opinion does not constitute a recommendation as to how to vote with respect to the Merger or any other matter and does not in any manner address the price at which the shares of Cornerstone common stock will trade at any time.

Qatalyst Partners’ opinion is necessarily based on financial, economic, market and other conditions as in effect on, and the information made available to it as of, the date of the opinion. Events occurring after the date of the opinion may affect Qatalyst Partners’ opinion and the assumptions used in preparing it, and Qatalyst Partners did not assume any obligation to update, revise or reaffirm its opinion. Qatalyst Partners’ opinion did not address the underlying business decision of Cornerstone to engage in the Merger, or the relative merits of the Merger as compared to any strategic alternatives that may be available to Cornerstone. Qatalyst Partners’ opinion is limited to the fairness, from a financial point of view, of the Merger Consideration to be received pursuant to, and in accordance with, the terms of the Merger Agreement by the holders of shares of Cornerstone common stock (other than Parent or any affiliate of Parent), and Qatalyst Partners expressed no opinion with respect to the fairness of the amount or nature of the compensation to any of the officers, directors or employees of Cornerstone or any of its affiliates, or any class of such persons, relative to such consideration.

The following is a summary of the material analyses performed by Qatalyst Partners in connection with its opinion dated August 5, 2021. The analyses and factors described below must be considered as a whole; considering any portion of such analyses or factors, without considering all analyses and factors, could create a misleading or incomplete view of the process underlying Qatalyst Partners’ opinion. For purposes of its analyses, Qatalyst Partners utilized both the Adjusted Internal Long Range Plan and the consensus of third-party research analysts’ projections as of August 4, 2021 (“Analyst Projections”). 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 Qatalyst Partners, 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 Qatalyst Partners’ financial analyses.

Qatalyst Partners performed an illustrative discounted cash flow analysis, which is designed to imply a range of potential per-share present values for Cornerstone common stock as of June 30, 2021 (which is the end of Cornerstone’s most recent completed fiscal quarter and most recent balance sheet date) by:

Based on the calculations set forth above, this analysis implied a range of per share values for Cornerstone common stock of approximately $41.63 to $76.14.

Qatalyst Partners compared selected financial information and public market multiples for Cornerstone with publicly available information and public market multiples for selected companies, which were selected by Qatalyst Partners in its professional judgment, based on factors including that they are publicly traded companies in similar lines of business to Cornerstone, have a similar business model, have similar financial performance or have other relevant or similar characteristics. The companies used in this comparison are listed below:

Based upon the Analyst Projections for calendar year 2022, and using the closing trading prices as of August 4, 2021, for shares of the selected companies, Qatalyst Partners calculated, among other things, the implied fully diluted enterprise value divided by the estimated consensus revenue for calendar year 2022 (the “CY2022E Revenue Multiples”) for each of the selected companies.

The CY2022E Revenue Multiple for Cornerstone was 4.5x based on the Analyst Projections, and the fully diluted enterprise value of Cornerstone was calculated using the closing price of Cornerstone common stock as of the Unaffected Date.

Based on the analysis of the CY2022E Revenue Multiples for the selected companies and the application of its professional judgment, Qatalyst Partners selected a representative range of 4.0x to 6.0x and applied this range to Cornerstone’s estimated calendar year 2022 revenue based on each of the Adjusted Internal Long Range Plan and the Analyst Projections. Based on the fully diluted shares of Cornerstone common stock (calculated utilizing the treasury stock method), which takes into account restricted stock units, performance-based restricted stock units and in-the-money stock options as of July 30, 2021 and inclusive of a subsequent August 2, 2021 RSU grant, all of which amounts were provided by Cornerstone’s management, and assuming net share settlement of in-the-money convertible debt, this analysis implied a range of per share values for Cornerstone common stock of approximately $37.13 to $60.41 based on the Adjusted Internal Long Range Plan and approximately $37.87 to $61.40 based on the Analyst Projections.

Based upon the Analyst Projections as of August 4, 2021, for calendar year 2022, and using the closing prices as of August 4, 2021, for shares of the selected companies, Qatalyst Partners calculated, among other things, the implied fully diluted equity value divided by the estimated consensus levered free cash flow for calendar year 2022 (the “CY2022E LFCF Multiples”) for each of the selected companies.

The CY2022E LFCF Multiple for Cornerstone was 13.2x based on the Analyst Projections, and the fully diluted equity value of Cornerstone was calculated using the closing price of Cornerstone common stock as of the Unaffected Date.

Based on the analysis of the CY2022E LFCF Multiples for each of the selected companies and the application of its professional judgment, Qatalyst Partners selected a representative range of 12.0x to 20.0x and applied this range to Cornerstone’s estimated calendar year 2022 levered free cash flow based on each of the Adjusted Internal Long Range Plan and the Analyst Projections. Based on the same fully diluted share count calculation as used for the analysis utilizing CY2022E Revenue Multiples above, this analysis implied a range of per share values for Cornerstone common stock of approximately $45.16 to $72.32 based on the Adjusted Internal Long Range Plan and approximately $40.15 to $64.33 based on the Analyst Projections.

No company included in the selected companies analysis is identical to Cornerstone. In evaluating the selected companies, Qatalyst Partners made judgments and assumptions with regard to industry performance, general business, economic, market and financial conditions and other matters. Many of these matters are beyond the control of Cornerstone, such as the impact of competition on Cornerstone’s business and the industry in general, industry growth and the absence of any material adverse change in Cornerstone’s financial condition and prospects or the industry or in the financial markets in general. Individual multiples or mathematical analysis, such as determining the arithmetic mean, median, or the high or low, is not in itself a meaningful method of using selected company data.

Qatalyst Partners compared 19 selected public software transactions announced since 2010 that had a deal value of $1 billion to $15 billion and targets with less than 15% growth and greater than 14% levered free cash flow margin. These transactions are listed below:

For each of the transactions listed above, Qatalyst Partners reviewed, among other things, (i) the implied fully diluted enterprise value of the target company as a multiple of third-party research analyst consensus estimates of the next-twelve-months revenue of the target company (“NTM Revenue Multiple”), (ii) the implied fully diluted enterprise value of the target company as a multiple of third-party research analyst consensus estimates of the next-twelve-months EBITDA of the target company (“NTM EBITDA Multiple”) and (c) the implied fully diluted equity value of the target company as a multiple third-party research analyst consensus estimates of the next-twelve-months levered free cash flow of the target company (“NTM LFCF Multiple”).

Based on the analysis of the NTM Revenue Multiple for each of the selected transactions, Qatalyst Partners selected a representative multiple range of 3.0x to 5.5x (which was chosen based on Qatalyst Partners’ professional judgment) and applied this range to Cornerstone’s estimated revenue for the twelve-month period ending on June 30, 2022, of $891 million based on the Analyst Projections. Based on the number of fully diluted shares of Cornerstone common stock (calculated utilizing the treasury stock method), which takes into account restricted stock units, performance-based restricted stock units and in-the-money stock options as of July 30, 2021, and inclusive of a subsequent August 2, 2021 RSU grant, all of which amounts were provided by Cornerstone’s management, and excluding shares underlying in-the-money convertible debt due to assuming cash settlement, including (if applicable) the value of any additional make-whole shares based on an assumed transaction close date of December 31, 2021, this analysis implied a range of per share values for Cornerstone common stock of approximately $23.77 to $53.27.

Based on the analysis of the NTM EBITDA Multiple for each of the selected transactions Qatalyst Partners selected a representative range of 10.5x to 20.0x (which was chosen based on Qatalyst Partners’ professional judgment) and applied that range to Cornerstone’s adjusted EBITDA for the twelve-month period ending on June 30, 2022 of $278 million, based on the Analyst Projections. Based on the same fully diluted share count calculation as used for the analysis utilizing NTM Revenue Multiples above, this analysis implied a range of per share values for Cornerstone common stock of approximately $27.21 to $61.60.

Based on the analysis of the NTM LFCF Multiple for each of the selected transactions Qatalyst Partners selected a representative range of 13.0x to 22.0x (which was chosen based on Qatalyst Partners’ professional judgment) and applied that range to Cornerstone’s estimated levered free cash flow for the twelve-month period ending on June 30, 2022 of $224 million based on the Analyst Projections (and increased to normalize for one-time Saba-related integration cash expenses over the same period). Based on the same fully diluted share count calculation as used for the analysis utilizing NTM Revenue Multiples above, this analysis implied a range of per share values for Cornerstone common stock of approximately $40.73 to $68.51.

No company or transaction utilized in the selected transactions analysis is identical to Cornerstone or the Merger. In evaluating the selected transactions, Qatalyst Partners made judgments and assumptions with regard to general business, market and financial conditions and other matters, many of which are beyond Cornerstone’s control, such as the impact of competition on Cornerstone’s business or the industry generally, industry growth and the absence of any material adverse change in Cornerstone’s financial condition and prospects or the industry or in the financial markets in general, which could affect the public trading value of the companies and the aggregate value of the transactions to which they are being compared. Individual multiples or mathematical analysis, such as determining the arithmetic mean, median, or the high or low, is not in itself a meaningful method of using selected company data. Because of the unique circumstances of each of these transactions and the Merger, Qatalyst Partners cautioned against placing undue reliance on this information.

In connection with the review of the Merger by our Board of Directors, Qatalyst Partners performed a variety of financial and comparative analyses for purposes of rendering its opinion. The preparation of a financial opinion is a complex process and is not necessarily amenable to a partial analysis or summary description. In arriving at its opinion, Qatalyst Partners considered the results of all of its analyses as a whole and did not attribute any particular weight to any analysis or factor it considered. Qatalyst Partners believes that selecting any portion of its analyses, without considering all analyses as a whole, could create a misleading or incomplete view of the process underlying its analyses and opinion. In addition, Qatalyst Partners may have given various analyses and factors more or less weight than other analyses and factors, and may have deemed various assumptions more or less probable than other assumptions. As a result, the ranges of valuations resulting from any particular analysis described above should not be taken to be Qatalyst Partners’ view of the actual value of Cornerstone. In performing its analyses, Qatalyst Partners made numerous assumptions with respect to industry performance, general business, economic, market and financial conditions and other matters, many of which are beyond Cornerstone’s control. Any estimates contained in Qatalyst Partners’ analyses are not necessarily indicative of future results or actual values, which may be significantly more or less favorable than those suggested by such estimates.

Qatalyst Partners conducted the analyses described above solely as part of its analysis of the fairness, from a financial point of view, of the Merger Consideration to be received pursuant to, and in accordance with, the

terms of the Merger Agreement by the holders of shares of Cornerstone common stock (other than Parent or any affiliate of Parent), to such holders. This analysis does not purport to be an appraisal or to reflect the price at which Cornerstone common stock might actually trade at any time.

Qatalyst Partners’ opinion and its presentation to our Board of Directors was one of many factors considered by our Board of Directors in deciding to approve the Merger Agreement. Consequently, the analyses as described above should not be viewed as determinative of the opinion of our Board of Directors with respect to the Merger Consideration to be received pursuant to, and in accordance with, the terms of the Merger Agreement by the holders of shares of Cornerstone common stock (other than Parent or any affiliate of Parent), or of whether our Board of Directors would have been willing to agree to different consideration. The Merger Consideration payable in the Merger was determined through arm’s-length negotiations between Cornerstone and Parent and was unanimously approved by our Board of Directors. Qatalyst Partners provided advice to Cornerstone during these negotiations. Qatalyst Partners did not, however, recommend any specific consideration to Cornerstone or that any specific consideration constituted the only appropriate consideration for the Merger.

Qatalyst Partners provides investment banking and other services to a wide range of entities and individuals, domestically and offshore, from which conflicting interests or duties may arise. In the ordinary course of these activities, affiliates of Qatalyst Partners may at any time hold long or short positions, and may trade or otherwise effect transactions in debt or equity securities or loans of Cornerstone, Parent or certain of their respective affiliates. During the two-year period prior to the date of Qatalyst Partners’ opinion, no material relationship existed between Qatalyst Partners or any of its affiliates and Cornerstone or Parent pursuant to which compensation was received by Qatalyst Partners or its affiliates. Qatalyst Partners and/or its affiliates may in the future provide investment banking and other financial services to Cornerstone, Parent, or Clearlake and their respective affiliates for which Qatalyst Partners would expect to receive compensation.

Qatalyst Partners provided Cornerstone with financial advisory services in connection with the proposed Merger for which it will be paid approximately $45,000,000, $4,000,000 of which was payable upon the delivery of its opinion (regardless of the conclusion reached in the opinion), and the remaining portion of which will be paid upon, and subject to, the consummation of the Merger. Cornerstone has also agreed to reimburse Qatalyst Partners for its expenses incurred in performing its services. Cornerstone has also agreed to indemnify Qatalyst Partners and its affiliates, their respective members, directors, officers, partners, agents and employees and any person controlling Qatalyst Partners or any of its affiliates against certain liabilities, including liabilities under federal securities law, and certain expenses related to or arising out of Qatalyst Partners’ engagement.

On August 5, 2021, Centerview rendered to the Board of Directors its oral opinion, subsequently confirmed in a written opinion dated August 5, 2021, that, as of such date and based upon and subject to various assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, the Merger Consideration to be paid to the holders of shares of Cornerstone common stock (other than Excluded Shares) pursuant to the Merger Agreement was fair, from a financial point of view, to such holders.

The full text of Centerview’s written opinion, dated August 5, 2021, which describes the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, is attached as Annex C and is incorporated herein by reference. The summary of the written opinion of Centerview set forth below is qualified in its entirety to the full text of Centerview’s written opinion attached as Annex C. Centerview’s financial advisory services and opinion were provided for the information and assistance of the Board of Directors (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transaction and Centerview’s opinion only addressed the fairness, from a financial point of view, as of the date thereof, to the holders of shares of Cornerstone common stock (other than Excluded Shares) of the Merger Consideration to be paid to such holders pursuant to the Merger Agreement. Centerview’s opinion did not address any other term or aspect of the Merger Agreement or the Transaction and does not constitute a recommendation to any stockholder of Cornerstone or any other person as to how such stockholder or other person should vote with respect to the Merger or otherwise act with respect to the Transaction or any other matter.

The full text of Centerview’s written opinion should be read carefully in its entirety for a description of the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion.

In connection with rendering the opinion described above and performing its related financial analyses, Centerview reviewed, among other things:

Centerview also participated in discussions with members of the senior management and representatives of Cornerstone regarding their assessment of the Internal Data. In addition, Centerview reviewed publicly available financial and stock market data, including valuation multiples, for Cornerstone and compared that data with similar data for certain other companies, the securities of which are publicly traded, in lines of business that Centerview deemed relevant. Centerview also compared certain of the proposed financial terms of the Transaction with the financial terms, to the extent publicly available, of certain other transactions that Centerview deemed relevant, and conducted such other financial studies and analyses and took into account such other information as Centerview deemed appropriate.

Centerview assumed, without independent verification or any responsibility therefor, the accuracy and completeness of the financial, legal, regulatory, tax, accounting and other information supplied to, discussed with, or reviewed by Centerview for purposes of its opinion and, with Cornerstone’s consent, Centerview relied upon such information as being complete and accurate. In that regard, Centerview assumed, at Cornerstone’s direction, that the Internal Data (including, without limitation, the Adjusted Internal Long Range Plan) were reasonably prepared on bases reflecting the best currently available estimates and judgments of the management of Cornerstone as to the matters covered thereby and Centerview relied, at Cornerstone’s direction, on the Internal Data for purposes of Centerview’s analysis and opinion. Centerview expressed no view or opinion as to the Internal Data or the assumptions on which it was based. In addition, at Cornerstone’s direction, Centerview did not make any independent evaluation or appraisal of any of the assets or liabilities (contingent, derivative, off-balance-sheet or otherwise) of Cornerstone, nor was Centerview furnished with any such evaluation or appraisal, and was not asked to conduct, and did not conduct, a physical inspection of the properties or assets of Cornerstone. Centerview assumed, at Cornerstone’s direction, that the final executed Merger Agreement would not differ in any respect material to Centerview’s analysis or opinion from the Draft Merger Agreement reviewed by Centerview. Centerview also assumed, at Cornerstone’s direction, that the Transaction will be consummated on the terms set forth in the Merger Agreement and in accordance with all applicable laws and other relevant documents or requirements, without delay or the waiver, modification or amendment of any term, condition or agreement, the effect of which would be material to Centerview’s analysis or Centerview’s opinion and that, in the course of obtaining the necessary governmental, regulatory and other approvals, consents, releases and waivers for the Transaction, no delay, limitation, restriction, condition or other change will be imposed, the effect of which would be material to Centerview’s analysis or Centerview’s opinion. Centerview did not evaluate and did not express any opinion as to the solvency or fair value of Cornerstone, or the ability of Cornerstone to pay its obligations when they come due, or as to the impact of the Transaction on such matters, under any state, federal or other laws relating to bankruptcy, insolvency or similar matters. Centerview is not a legal, regulatory, tax or accounting advisor, and Centerview expressed no opinion as to any legal, regulatory, tax or accounting matters.

Centerview’s opinion expressed no view as to, and did not address, Cornerstone’s underlying business decision to proceed with or effect the Transaction, or the relative merits of the Transaction as compared to any alternative business strategies or transactions that might be available to Cornerstone or in which Cornerstone might engage. Centerview’s opinion was limited to and addressed only the fairness, from a financial point of view, as of the date of Centerview’s written opinion, to the holders of shares of Cornerstone common stock (other than Excluded Shares) of the Merger Consideration to be paid to such holders pursuant to the Merger Agreement. For purposes of its opinion, Centerview was not asked to, and Centerview did not, express any view on, and its opinion did not address, any other term or aspect of the Merger Agreement or the Transaction, including, without limitation, the structure or form of the Transaction, or any other agreements or arrangements contemplated by the Merger Agreement or entered into in connection with or otherwise contemplated by the Transaction, including, without limitation, the fairness of the Transaction or any other term or aspect of the Transaction to, or any consideration to be received in connection therewith by, or the impact of the Transaction on, the holders of any other class of securities, creditors or other constituencies of Cornerstone or any other party. In addition, Centerview expressed no view or opinion as to the fairness (financial or otherwise) of the amount, nature or any other aspect of any compensation to be paid or payable to any of the officers, directors or employees of Cornerstone or any party, or class of such persons in connection with the Transaction, whether relative to the Merger Consideration to be paid to the holders of shares of Cornerstone common stock (other than Excluded Shares) pursuant to the Merger Agreement or otherwise. Centerview’s opinion was necessarily based on financial, economic, monetary, currency, market and other conditions and circumstances as in effect on, and the information made available to Centerview as of, the date of Centerview’s written opinion, and Centerview does not have any obligation or responsibility to update, revise or reaffirm its opinion based on circumstances, developments or events occurring after the date of Centerview’ written opinion. Centerview’s opinion does not constitute a recommendation to any stockholder of Cornerstone or any other person as to how such stockholder or other person should vote with respect to the Merger or otherwise act with respect to the Transaction or any other matter. Centerview’s financial advisory services and its written opinion were provided for the information and assistance of the Board of Directors (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transaction. The issuance of Centerview’s opinion was approved by the Centerview Partners LLC Fairness Opinion Committee.

The following is a summary of the material financial analyses prepared and reviewed with the Board of Directors in connection with Centerview’s opinion, dated August 5, 2021. The summary set forth below does not purport to be a complete description of the financial analyses performed or factors considered by, and underlying the opinion of, Centerview, nor does the order of the financial analyses described represent the relative importance or weight given to those financial analyses by Centerview. Centerview may have deemed various assumptions more or less probable than other assumptions, so the reference ranges resulting from any particular portion of the analyses summarized below should not be taken to be Centerview’s view of the actual value of Cornerstone. Some of the summaries of the financial analyses set forth below include information presented in tabular format. In order to fully understand the financial analyses, the tables must be read together with the text of each summary, as the tables alone do not constitute a complete description of the financial analyses performed by Centerview. Considering the data in the tables below without considering all financial analyses or factors or the full narrative description of such analyses or factors, including the methodologies and assumptions underlying such analyses or factors, could create a misleading or incomplete view of the processes underlying Centerview’s financial analyses and its opinion. In performing its analyses, Centerview made numerous assumptions with respect to industry performance, general business and economic conditions and other matters, many of which are beyond the control of Cornerstone or any other parties to the Transaction. None of Cornerstone, Parent, Merger Sub or Centerview or any other person assumes responsibility if future results are materially different from those discussed. Any estimates contained in these analyses are not necessarily indicative of actual values or predictive of future results or values, which may be significantly more or less favorable than as set forth below. In addition, analyses relating to the value of Cornerstone do not purport to be appraisals or reflect the prices at which Cornerstone may actually be sold. Accordingly, the assumptions and estimates used in, and the results derived from, the financial analyses are inherently subject to substantial uncertainty. Except as otherwise noted, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before August 5, 2021, the last trading day before the public announcement of the Transaction, and is not necessarily indicative of current market conditions.

Centerview reviewed certain financial information of Cornerstone and compared it to corresponding financial information of certain publicly traded companies that Centerview selected, based on its experience and professional judgment (which are referred to as the “selected companies” in this summary of Centerview’s opinion). Although none of the selected companies is directly comparable to Cornerstone, the companies listed below were chosen by Centerview because, among other reasons, they are publicly traded companies with certain operational, business and/or financial characteristics that, for purposes of Centerview’s analysis, may be considered similar to those of Cornerstone.

However, because none of the selected companies is exactly the same as Cornerstone, Centerview believed that it was inappropriate to, and therefore did not, rely solely on the quantitative results of the selected public company analysis. Accordingly, Centerview also made qualitative judgments, based on its experience and professional judgment, concerning differences between the operational, business and/or financial characteristics of Cornerstone and the selected companies that could affect the public trading values of each in order to provide a context in which to consider the results of the quantitative analysis.

Using publicly available information obtained from SEC filings and other data sources as of August 4, 2021, Centerview calculated, for each selected company, among other things, (i) such company’s implied fully-diluted enterprise value divided by the CY2022E Revenue Multiples and (ii) such company’s CY2022E LFCF Multiples.

The selected companies are summarized below:

Based on its analysis and other considerations that Centerview deemed relevant in its professional judgment and experience, Centerview selected a reference range of CY2022E Revenue Multiples of 4.5x to 6.0x and a reference range of CY2022E LFCF Multiples of 12.0x to 20.0x. In selecting these ranges of CY2022E Revenue Multiples and CY2022E LFCF Multiples, Centerview made qualitative judgments based on its experience and professional judgment concerning differences between the business, financial and operating characteristics of Cornerstone and the selected companies that could affect their public trading values in order to provide a context in which to consider the results of the quantitative analysis.

Centerview applied the reference range of CY2022E Revenue Multiples to Cornerstone’s 2022E Revenue of $908 million, as provided by management of Cornerstone. Centerview then divided the result of the foregoing calculations by the number of fully-diluted shares of Cornerstone common stock outstanding (determined using the treasury stock method and taking into account outstanding restricted stock units, performance stock units and deferred stock units and assuming net-share settlement of in-the-money convertible debt) as of August 2, 2021, as set forth in the Internal Data, to derive a range of implied values per share of Cornerstone common stock of $43.25 to $60.50, rounded to the nearest $0.25.

Centerview applied the reference range of CY2022E LFCF Multiples to Cornerstone’s 2022E levered free cash flow of $271 million, as provided by management of Cornerstone. Centerview then divided the result of the foregoing calculations by the number of fully-diluted shares of Cornerstone common stock outstanding (determined using the treasury stock method and taking into account outstanding restricted stock units, performance stock units and deferred stock units and assuming net-share settlement of in-the-money convertible debt) as of August 2, 2021, as set forth in the Internal Data, to derive a range of implied values per share of Cornerstone common stock of $45.00 to $72.25, rounded to the nearest $0.25.

Centerview compared both of these ranges to the Merger Consideration of $57.50 per share in cash, without interest, to be paid to the holders of Cornerstone common stock (other than Excluded Shares) pursuant to the Merger Agreement.

Centerview reviewed and compared certain information relating to the following selected transactions that Centerview, based on its experience and professional judgment (which are referred to as the “selected transactions” in this summary of Centerview’s opinion), deemed relevant to consider in relation to Cornerstone and the Merger.

However, because none of the selected transactions used in this analysis is identical or directly comparable to the Merger, Centerview believed that it was inappropriate to, and therefore did not, rely solely on the quantitative results of the selected transaction analysis. Accordingly, Centerview also made qualitative judgments, based on its experience and professional judgment, concerning differences between the operational, business or financial characteristics of Cornerstone and each target company as well as the Merger and the selected transactions that could affect the transaction values of each in order to provide a context in which to consider the results of the quantitative analysis. Although none of the selected transactions is directly comparable to the Merger, the selected transactions listed below were selected, among other reasons, based on Centerview’s experience and professional judgment, because the selected transactions have certain characteristics that, for the purposes of this analysis, may be considered similar to certain characteristics of the Merger. The reasons for and the circumstances surrounding each of the selected transactions analyzed were diverse and there are inherent differences in the business, operations, financial conditions and prospects of Cornerstone and the target companies included in the selected transactions analysis.

Using publicly available information obtained from SEC filings, Wall Street research, Capital IQ and other data sources, Centerview calculated, for each selected transaction, among other things, (i) the NTM Revenue Multiple and (ii) the NTM EBITDA Multiple for each selected transaction.

The selected transactions considered in this analysis are summarized below:

Based on its analysis of the relevant metrics for each of the target companies in the selected transactions and other considerations that Centerview deemed relevant in its professional judgment and experience, Centerview selected a reference range of NTM Revenue Multiples of 3.5x to 5.0x and NTM EBITDA Multiples of 14.0x to 20.0x. In selecting these reference ranges, Centerview made qualitative judgments based on its

experience and professional judgment concerning differences between the business, financial and operating characteristics and prospects of Cornerstone and the target companies included in the selected transactions and other factors that could affect the public trading, acquisition or other values of such companies or Cornerstone.

Centerview applied these reference ranges to Cornerstone’s projected NTM Revenue of $883 million and NTM EBITDA of $312 million as of June 30, 2021, to derive a range of implied enterprise values for Cornerstone. Centerview subtracted from this range of implied enterprise values Cornerstone’s net debt of approximately $979 million as of June 30, 2021, as provided by management of Cornerstone, to derive a range of implied equity values for Cornerstone.

Centerview then divided the result of the foregoing calculations by the number of fully-diluted shares of Cornerstone common stock outstanding (determined using the treasury stock method and taking into account outstanding restricted stock units, performance stock units and deferred stock units and assuming cash settlement of in-the-money convertible notes, including (if applicable) the value of any additional make-whole shares based on an assumed transaction close date of December 31, 2021) as of August 2, 2021, as set forth in the Internal Data, to derive a range of implied values per share of Cornerstone common stock of $29.50 to $47.00 for Cornerstone’s NTM Revenue and $46.50 to $70.25 for Cornerstone’s NTM EBITDA, each rounded to the nearest $0.25.

Centerview compared this range to the Merger Consideration of $57.50 per share in cash, without interest, to be paid to the holders of Cornerstone common stock (other than Excluded Shares) pursuant to the Merger Agreement.

Centerview performed a discounted cash flow analysis of Cornerstone based on the Adjusted Internal Long Range Plan. A discounted cash flow analysis is a traditional valuation methodology used to derive a valuation of an asset or set of assets by calculating the “present value” of estimated future cash flows of the asset or set of assets. “Present value” refers to the current value of future cash flows and is obtained by discounting those future cash flows by a discount rate that takes into account macroeconomic assumptions and estimates of risk, the opportunity cost of capital, expected returns and other appropriate factors.

In performing this analysis, Centerview calculated an implied per share equity range for the shares of Cornerstone common stock by discounting to present value as of June 30, 2021, using discount rates ranging from 8.25% to 10.00% (reflecting Centerview’s analysis of Cornerstone’s weighted average cost of capital) and the mid-year convention, the forecasted unlevered free cash flows of Cornerstone (burdened for stock-based compensation expense based on discussions with Cornerstone management) based on the Adjusted Internal Long Range Plan for calendar year 2021 through calendar year 2025. The implied terminal value of Cornerstone at the end of the forecast period was estimated by using terminal unlevered free cash flow multiples ranging from 15.0x to 20.0x (which were chosen based on Centerview’s professional judgment).

Based on its analysis, Centerview calculated a range of implied enterprise values of Cornerstone. Centerview subtracted from this range of implied enterprise values Cornerstone’s net debt of approximately $979 million as of June 30, 2021, as provided by management of Cornerstone, to derive a range of implied equity values for Cornerstone. Centerview then divided the result of the foregoing calculations by the number of fully-diluted shares of Cornerstone common stock outstanding (determined using the treasury stock method and taking into account outstanding restricted stock units, performance stock units and deferred stock units outstanding and assuming net-share settlement of in-the-money convertible debt) as of August 2, 2021, as set forth in the Internal Data, to derive a range of implied values of Cornerstone common stock of $50.75 to $71.25 per share, rounded to the nearest $0.25.

Centerview compared this range to the Merger Consideration of $57.50 per share in cash, without interest, to be paid to the holders of Cornerstone common stock (other than Excluded Shares) pursuant to the Merger Agreement.

Centerview noted for the Board of Directors certain additional factors solely for informational purposes, including, among other things, the following:

The preparation of a financial opinion is a complex analytical process involving various determinations as to the most appropriate and relevant methods of financial analysis and the application of those methods to the particular circumstances and, therefore, a financial opinion is not readily susceptible to summary description. In arriving at its opinion, Centerview did not draw, in isolation, conclusions from or with regard to any factor or analysis that it considered. Rather, Centerview made its determination as to fairness on the basis of its experience and professional judgment after considering the results of all of the analyses.

Centerview’s financial analyses and opinion were only one of many factors taken into consideration by the Board of Directors in its evaluation of the Transaction. Consequently, the analyses described above should not be viewed as determinative of the views of the Board of Directors or the management of Cornerstone with respect to the Merger Consideration or as to whether the Board of Directors would have been willing to determine that a different consideration was fair. The Merger Consideration was determined through arm’s-length negotiations between Cornerstone and Parent and was approved by the Board of Directors. Centerview provided advice to Cornerstone during these negotiations. Centerview did not, however, recommend any specific amount of consideration to Cornerstone or the Board of Directors or that any specific amount of consideration constituted the only appropriate consideration for the Transaction.

Centerview is a securities firm engaged directly and through affiliates and related persons in a number of investment banking, financial advisory and merchant banking activities. In the two years prior to the date of its written opinion, Centerview was engaged to provide financial advisory services to Cornerstone, including in connection with its acquisition of Saba in 2020, and Centerview has received approximately $9 million in compensation from Cornerstone for such services. In the two years prior to the date of its written opinion, Centerview had not been engaged to provide financial advisory or other services to Parent, Merger Sub or Clearlake, and Centerview had not received any compensation from Parent, Merger Sub or Clearlake. Centerview may provide financial advisory and other services to or with respect to Cornerstone or Parent or their respective affiliates and portfolio companies of Clearlake in the future, for which Centerview may receive compensation. Certain (i) of Centerview’s and its affiliates’ directors, officers, members and employees, or family members of such persons, (ii) of Centerview’s affiliates or related investment funds and (iii) investment funds or other persons in which any of the foregoing may have financial interests or with which they may co-invest, may at any time acquire, hold, sell or trade, in debt, equity and other securities or financial instruments (including

derivatives, bank loans or other obligations) of, or investments in, Cornerstone, Parent, Clearlake or any of their respective affiliates and portfolio companies of Clearlake, or any other party that may be involved in the Transaction.

The Board of Directors selected Centerview as its financial advisor in connection with the Transaction based on Centerview’s reputation and experience. Centerview is an internationally recognized investment banking firm that has substantial experience in transactions similar to the Transaction.

In connection with Centerview’s services as the financial advisor to the Board of Directors, Cornerstone has agreed to pay Centerview an aggregate fee of $24 million, $4 million of which was payable upon the rendering of Centerview’s opinion and the remainder of which is payable contingent upon consummation of the Transaction. In addition, Cornerstone has agreed to reimburse certain of Centerview’s expenses arising, and to indemnify Centerview against certain liabilities that may arise, out of Centerview’s engagement.

When considering the recommendation of the Board of Directors that you vote to approve the proposal to adopt the Merger Agreement, you should be aware that our directors and executive officers may have interests in the Merger that are different from, or in addition to, the interests of stockholders generally, as more fully described below. The Board of Directors was aware of and considered these interests, among other matters, to the extent that they existed at the time, in reaching the determination that the terms and conditions of the Merger and the Merger Agreement were fair to, advisable and in the best interests of the Company and its stockholders, in reaching its decision to approve and adopt the Merger Agreement and in making their recommendation that our stockholders vote in favor of the adoption of the Merger Agreement. For additional information regarding the interests of our directors and executive officers in the Merger, see the section of this proxy statement captioned “The Merger — Interests of Cornerstone’s Directors and Executive Officers in the Merger”.

As of the date of this proxy statement, none of our executive officers has entered into any agreement with Parent or any of its affiliates regarding employment with, or the right to purchase or participate in the equity of, the Surviving Corporation or one or more of its affiliates. Prior to and following the Closing of the Merger, however, certain of our executive officers may have discussions, and following the Closing of the Merger, may enter into agreements with, Parent or Merger Sub, their subsidiaries or their respective affiliates regarding employment with, or the right to purchase or participate in the equity of, the Surviving Corporation or one or more of its affiliates.

Under the Merger Agreement, all existing rights to indemnification, advancement of expenses and exculpation, for acts and omissions occurring prior to the Effective Time, in favor of current and former directors and officers of Cornerstone and its subsidiaries (each, an “Indemnified Persons”), as provided in the certificate of incorporation, bylaws, or applicable governing documents of Cornerstone or its subsidiaries and as provided in the indemnification agreements between Cornerstone and its subsidiaries and each Indemnified Person, will (i) survive the Merger, (ii) not be amended, repealed or otherwise modified in any manner that would adversely affect the rights of the Indemnified Persons, and (iii) be observed by the Surviving Corporation and its subsidiaries to the fullest extent available under Delaware law for a period of six years from the Effective Time. Any claim made pursuant to such rights within such six-year period will continue to be subject to the Merger Agreement and the rights provided under the Merger Agreement until disposition of such claim.

Additionally, from the Effective Time until the sixth anniversary of the Effective Time, (A) Parent and the Surviving Corporation will, to the fullest extent permitted under applicable legal requirements, indemnify and hold harmless each Indemnified Person in his or her capacity as an officer or director against all losses incurred by such Indemnified Person in connection with any legal proceeding based on or arising out of the fact that such Indemnified Person was a director or officer of Cornerstone or any of its subsidiaries at or prior to the Effective Time and (B) the Surviving Corporation will, and Parent will cause the Surviving Corporation to, maintain in effect the existing policy of directors’ and officers’ liability insurance maintained by Cornerstone and its subsidiaries as of the date of the Merger Agreement for the benefit of the Indemnified Persons who are currently covered by such existing policy with respect to their acts and omissions occurring prior to the Effective Time in

their capacities as directors and officers of Cornerstone and its subsidiaries (as applicable), on terms with respect to coverage, deductibles and amounts no less favorable than the existing policy (or at or prior to the Effective Time, Parent or Cornerstone may (through a nationally recognized insurance broker) purchase a six-year “tail” policy for the existing policy effective as of the Effective Time) and if such “tail policy” has been obtained, it will be deemed to satisfy all obligations to obtain and/or maintain insurance pursuant to the Merger Agreement. For more information, please see the section of this proxy statement captioned “Proposal 1: Adoption of the Merger Agreement—Indemnification and Insurance.”

Cornerstone from time to time has granted awards under its equity incentive plans of Company Options and Company RSUs.

As of August 20, 2021, there were 66,855,400 shares of common stock and 1,499,091 shares of common stock subject to outstanding Company Options, and 5,656,280 shares of common stock subject to outstanding Company RSUs.

The Merger Agreement provides that each Vested Company RSU, Vested Company Option and Director RSU will be cancelled and automatically converted into the right to receive an amount in cash equal to the product of (A) the aggregate number of shares subject to, or issuable in settlement of, such award immediately prior to the Effective Time, multiplied by (B) the Per Share Merger Consideration (or, for each Company Option, the excess, if any, of the Per Share Merger Consideration over such Company Option’s per share exercise price), subject to any required withholding of taxes. For more information, please see the section of this proxy statement captioned “Proposal 1: Adoption of the Merger Agreement—Merger Consideration—Common Stock.”

Each Unvested Award will be cancelled and automatically converted into the right to receive the Unvested Consideration Amount, which Unvested Consideration Amount will, be paid at the same time(s) that the unvested awards would have vested in accordance with their terms and will remain subject to the holder of the Unvested Awards remaining in continuous service with Parent, the Surviving Corporation or any of its Subsidiaries through each such vesting date (except, that any terms and conditions relating to accelerated vesting upon a termination of the holder’s employment in connection with or following the Merger will continue to apply to the Unvested Consideration Amount). For the avoidance of doubt, any Company Options (whether a Vested Company Option or an Unvested Company Option) with a per share exercise price equal to or greater than the Per Share Merger Consideration will be cancelled immediately upon the Effective Time without payment or consideration. For more information, please see the section of this proxy statement captioned “Proposal 1: Adoption of the Merger Agreement—Merger Consideration—Treatment of Company Options and Company RSUs.”

We entered into a change of control severance agreement with Philip S. Saunders, our chief executive officer, effective as of May 3, 2021. Mr. Saunders’ change of control severance agreement provides that if his employment is terminated by us or our successor without “cause” (excluding as a result of his death or “disability”) (each, as defined in his change of control severance agreement), or by Mr. Saunders for “good reason” (as defined in his change of control severance agreement) (in each case, a “qualifying termination”), and subject to Mr. Saunders signing and not revoking a release of claims, Mr. Saunders will receive (i) a lump sum payment equal to 150% of Mr. Saunders’ annual base salary as then in effect; (ii) a lump-sum amount equal to 150% of Mr. Saunders’ full target annual bonus; (iii) if such termination occurs after the completion of a bonus period but prior to the payment of any bonus, a lump-sum amount equal to the bonus Mr. Saunders would have received had he remained employed through the bonus payment date and based on actual performance; (iv) reimbursement of COBRA continuation premiums for up to 18 months for Mr. Saunders and his eligible dependents (provided he is eligible for and timely elects COBRA continuation coverage), or, in the discretion of

Cornerstone, cash payments in lieu thereof; and (v) 18 months accelerated vesting of all then-unvested shares subject to Mr. Saunders’ equity awards. However, if the qualifying termination occurs during the period that commences three months prior to a “change of control” (as defined in his change of control and severance agreement) and ends on the first anniversary following a change of control, then in addition to the benefits described above, but excluding part (iii) above, (A) 100% of Mr. Saunders’ then unvested equity awards will vest in full, provided that if the vesting of any such equity awards is to be determined based on the achievement of performance criteria, then such equity award will vest as stated in the equity award, or if no such vesting is specified, then will vest assuming the performance criteria had been achieved at 100% of target levels for the relevant performance period or periods; and (B) Mr. Saunders’ unvested stock options or stock appreciation rights will remain exercisable until the one year anniversary of the date of his termination of employment.

In May 2021, we entered into change of control severance agreements with each of Jeffrey Lautenbach, our president, Chirag Shah, our chief financial officer, Mark Goldin, our chief technology officer, Heidi Spirgi, our chief strategy and growth officer, and Adam Weiss, our chief administrative officer and general counsel. Each such executive’s change of control severance agreement provides that if his or her employment is terminated by us or our successor without “cause” (excluding as a result of his or her death or “disability”) (each, as defined in their change of control severance agreement), or by the executive for “good reason” (as defined in their change of control severance agreement) (in each case, a “qualifying termination”), and subject to such executive signing and not revoking a release of claims, each executive will receive (i) a lump sum payment equal to 100% of their annual base salary as then in effect; (ii) if such termination occurs after the completion of a bonus period but prior to the payment of any bonus, a lump-sum amount equal to the bonus such executive would have received had they remained employed through the bonus payment date and based on actual performance; (iii) reimbursement of COBRA continuation premiums for up to 12 months for the executive and their eligible dependents (provided they are eligible for and timely elects COBRA continuation coverage), or, in the discretion of Cornerstone, cash payments in lieu thereof; and (iv) 12 months accelerated vesting of all then-unvested shares subject to each executive’s equity awards. However, if the qualifying termination occurs during the period that commences three months prior to a “change of control” (as defined in their change of control and severance agreement) and ends on the first anniversary following a change of control, then each executive will receive (A) a lump sum payment equal to 100% of their annual base salary as then in effect; (B) a lump sum payment equal to 100% of their full annual target bonus; (C) reimbursement of COBRA continuation premiums for up to 12 months for the executive and their eligible dependents (provided they are eligible for and timely elects COBRA continuation coverage), or, in the discretion of Cornerstone, cash payments in lieu thereof; (D)100% of the executive’s then unvested equity awards will vest in full, provided that if the vesting of any such equity awards is to be determined based on the achievement of performance criteria, then such equity award will vest as stated in the equity award, or if no such vesting is specified, then will vest assuming the performance criteria had been achieved at 100% of target levels for the relevant performance period or periods; and (E) the executive’s unvested stock options or stock appreciation rights will remain exercisable until the one year anniversary of the date of their termination of employment.

Each executive officer’s change of control and severance agreement provides that, in the event any of the payments provided for under the change of control severance agreement or otherwise payable to the executive officer would constitute “parachute payments” within the meaning of Section 280G of the Internal Revenue Code and could be subject to the related excise tax under Section 4999 of the Internal Revenue Code, they would be entitled to receive either full payment of benefits or such lesser amount that would result in no portion of the benefits being subject to the excise tax, whichever results in the greater amount of after-tax benefits to the executive. However, please see the section below, entitled “Sections 280G and 4999 of the Code.”

Each executive officer’s receipt of the severance benefits under their change of control severance agreement is subject to them signing a standard separation agreement and release of claims with Cornerstone and provided that such release becomes effective and irrevocable no later than 60 days following their termination of employment. Each executive officer is also subject to obligations related to non-solicitation of employees of Cornerstone and its affiliates for a period of 12 months following the date the executive’s employment terminates for any reason, and the provisions of an employee confidentiality, non-disclosure, and assignment of inventions agreement.

For the purposes of each executive officer’s change of control severance agreement, “cause” generally means (i) an act of material dishonesty made by the executive in connection with the executive’s carrying out his or her job responsibilities to Cornerstone intended to result in substantial personal enrichment of the executive; (ii) the executive’s conviction of, or plea of nolo contendere to a felony which the Board of Directors reasonably believes had or will have a material detrimental effect on Cornerstone’s reputation or business; (iii) a willful act by the executive which constitutes gross misconduct and which is injurious to Cornerstone or its affiliates; (iv) the executive’s willful and material breach of their change of control severance agreement, including without limitation, their intentional failure to perform their stated duties, and their continued failure to cure such breach to the reasonable satisfaction of the Board of Directors within 10 days following written notice of such breach to the executive; and (v) the executive’s material violation of a Company policy that results in a material detrimental effect on Cornerstone’s reputation or business.

For the purposes of each executive officer’s change of control severance agreement, “good reason” generally means the executive officer’s resignation within 30 days following the expiration of any cure period (discussed below) following the occurrence of one or more of the following, without the executive officer’s express written consent: (i) a significant reduction or adverse change in the executive’s duties, position, reporting relationship or responsibilities, or the removal of the executive from such duties, position or responsibilities; (ii) a material reduction in the executive officer’s base salary (except where there is a reduction applicable to the management team generally, such reduction does not have a disproportionate effect on the executive in comparison to other members of the senior management team, and such reduction does not to exceed 10% of the executive’s base salary); (iii) a reduction by Cornerstone in the kind or level of benefits to which the executive is entitled with the result that the executive’s overall benefits package is significantly reduced disproportionately to other members of senior management; (iv) a material breach by Cornerstone of a term of any agreement between Cornerstone and the executive; and (v) the relocation of the executive to a facility or location more than 35 miles from the executive’s present employment location. An executive officer will not resign for “good reason” without first providing Cornerstone with written notice of the acts or omissions constituting the grounds for “good reason” within 90 days of the initial existence of the grounds for “good reason” and a reasonable cure period of 30 days following the date Cornerstone receives such notice during which such condition must not have been cured.

In accordance with Item 402(t) of Regulation S-K, the table below sets forth the compensation that is based on or otherwise relates to the Merger that will or may become payable to certain executive officers in connection with the Merger. Please see the section of this proxy statement captioned “—Payments Upon Termination At or Following Change in Control” for further information regarding this compensation.

The table below assumes that: (i) for the purposes of this table only that, the Closing of the Merger occurs on August 20, 2021; (ii) the employment of Messrs. Saunders, Lautenbach, Shah, Weiss and Goldin and Mses. Spirgi and Coughlin be terminated immediately following the Closing of the Merger in a manner entitling the named executive officer to receive the severance benefits described in the section of this proxy statement captioned “—Payments Upon Termination At or Following Change in Control”; (iii) no named executive officer receives any additional equity grants on or prior to the Closing of the Merger; and (iv) no named executive officer enters into new agreements or is otherwise legally entitled to, prior to the Closing of the Merger,

additional compensation or benefits. Pursuant to applicable proxy disclosure rules, the value of the equity award acceleration below is calculated based on the number of shares covered by the applicable Company Option or Company RSU that are accelerating multiplied by $57.50 per share (less the applicable exercise price per share in the case of Company Options). The amounts shown in the table below do not include the value of payments or benefits that would have been earned, or any amounts associated with equity awards that would vest pursuant to their terms, on or prior to the Closing of the Merger, or the value of payments or benefits that are not based on or otherwise related to the Merger.

In addition to the assumptions described in the preceding paragraph, the amounts set forth in the table below are based on certain other assumptions that are described in the footnotes accompanying the table below. The assumptions based upon which we have estimated the amounts in the table below may or may not actually occur. Accordingly, the ultimate amounts to be received by a named executive officer in connection with the Merger may differ from the amounts set forth below.

As discussed above at “Treatment of Company Options and Company RSUs”, at the Effective Time, each Vested Award (including those held by our executive officers and non-employee directors) will be cancelled and automatically converted into the right to receive the applicable Vested Award Cash-out Payment, and each

Unvested Award (including those held by our executive officers) will be cancelled and automatically converted into the right to receive the an amount in cash equal to the product of (i) the aggregate number of shares subject to, or issuable in settlement of, such award immediately prior to the Effective Time, multiplied by (ii) the Per Share Merger Consideration (or, for each Company Option, the excess, if any, of the Per Share Merger Consideration over such Company Option’s per share exercise price), subject to any required withholding of taxes and subject to the vesting conditions (including any accelerated vesting on specific terminations of employment) and payment terms described above.

Each of our executive officers is eligible to receive the applicable vesting acceleration benefits with respect to his or her equity awards described above under the heading “Payments Upon Termination At or Following Change in Control”.

The following table sets forth the number of shares of common stock and the number of shares of common stock underlying equity awards held by each of Cornerstone’s executive officers and non-employee directors that are outstanding as of August 20, 2021. The table also sets forth the values of these shares and equity awards, determined as the number of shares multiplied by the Per Share Merger Consideration (minus the applicable per share exercise price for any Company Options). No additional shares of common stock or equity awards were granted to any executive officer or non-employee director in contemplation of the Merger.

Parent and Merger Sub have represented to Cornerstone that they will have available to them, together with Cornerstone’s cash on hand, sufficient funds to pay the fees and expenses required to be paid at the closing of the Merger by Parent and Merger Sub under the Merger Agreement. This includes funds needed to: (i) pay Cornerstone stockholders the amounts due under the Merger Agreement for their respective common stock, (ii) make payments in respect of our outstanding Company Options and Company RSUs payable at Closing and (iii) make payments of all amounts required to be paid in connection with the Merger pursuant to the Indenture and the Cornerstone Convertible Notes. We anticipate that the total amount of funds necessary to complete the Merger and the related transactions, including to pay the Merger Consideration, make the required payments with respect to Company Options and Company RSUs payable at Closing, repay the Company’s outstanding indebtedness and to make payments required with respect to the Cornerstone Convertible Notes, as well as to pay the fees and expenses required to be paid at the Closing of the Merger by the Company, Parent and Merger Sub under the Merger Agreement, will be approximately $5,300,000,000.

In connection with the financing of the Merger, Parent and/or Merger Sub have obtained committed financing consisting of (i) equity to be provided by the Guarantors pursuant to the terms of the Clearlake Equity Commitment Letter (ii) preferred equity to be provided by the Investors pursuant to the Preferred Equity Commitment Letter and (iii) debt financing to be provided pursuant to the Debt Commitment Letter by the lenders party thereto. In connection with the Merger Agreement, Parent and Merger Sub have delivered to Cornerstone copies of the Financing Letters. Notwithstanding anything in the Merger Agreement to the contrary, in no event will the receipt or availability of any funds or financing (including the financing contemplated by the Financing Letters) by or to Parent or any of its affiliates or any other financing transaction be a condition to any of the obligations of Parent or Merger Sub under the Merger Agreement.

Merger Sub has entered into the Debt Commitment Letter with JPMorgan Chase Bank, N.A., Bank of America, N.A. and certain other financial institutions (collectively, the “Lenders”), pursuant to which, subject to the terms and conditions set forth therein, the lenders thereunder have committed to provide debt financing in an aggregate principal

amount of up to $3,187,500,000, of which up to $2,937,500,000 will be available at Closing to consummate the Merger and pay related fees, costs and expenses. The Lenders’ obligation to provide the Debt Financing is subject to certain conditions, including, but not limited to, the following (subject to certain exceptions and qualifications as set forth in the Debt Commitment Letter):

The Lender’s commitments under the Debt Commitment Letter automatically terminate upon the earliest to occur of: (i) five business days after February 5, 2022 (as such date may be extended in accordance with the Merger Agreement as in effect on the date of the Debt Commitment Letter), (ii) the initial funding date of the Debt Financing under the Debt Commitment Letter, (iii) five business days following the termination of the Merger Agreement in accordance with its terms without the funding of the Debt Financing, and (iv) the consummation of the Merger without the funding of the debt commitment.

As of the date hereof, the documentation governing the Debt Financing contemplated by the Debt Commitment Letter has not been finalized and, accordingly, the actual terms of the Debt Financing may differ from those described in this proxy statement.

In connection with the execution of the Merger Agreement, the Guarantors have delivered the Clearlake Equity Commitment Letter to Parent, and the Investors have provided a Preferred Equity Commitment Letter, pursuant to which, upon the terms and subject to the conditions set forth in the Equity Commitment Letters, the Guarantors have committed to contribute, the Guarantors have committed to contribute an aggregate amount of up to $1,935,000,000, and the Investors have committed to contribute an aggregate amount of up to $700,000,000, respectively, to Parent in connection with the Merger solely for the purpose of funding the Required Amounts. The Guarantors may assign some or all of their respective obligations under the Clearlake Equity Commitment Letter to any of their respective affiliates, co-investment funds or, subject to certain conditions being met, other investors.

The obligation of the Guarantors to fund the equity commitment under the Clearlake Equity Commitment Letter is subject to the following conditions:

The obligation of each Guarantor to fund the equity commitment under the Clearlake Equity Commitment Letter will automatically and immediately terminate upon the earliest to occur of (i) the funding of each Guarantor’s respective commitment, (ii) the consummation of the Closing pursuant to the Merger Agreement, (iii) the valid termination of the Merger Agreement in accordance with its terms (iv) Cornerstone commencing any legal proceeding to enforce the payment of all or any portion of the Parent Termination Fee under the Limited Guarantee or (v) Cornerstone or any of its controlled affiliates, officers or directors commencing any legal proceeding against any Guarantor or certain related parties of any Guarantor asserting any claim (whether in tort, contract or otherwise) under, or in respect of, the Merger Agreement, the Equity Commitment Letters, the Debt Commitment Letter, the Limited Guarantee, or any transaction contemplated thereby.

Cornerstone is an express third-party beneficiary of the Clearlake Equity Commitment Letter solely with respect to enforcing Parent’s right to cause the commitment under the Clearlake Equity Commitment Letter by each Guarantor to be funded to Parent in accordance with the Clearlake Equity Commitment Letter, and to cause Parent to enforce its rights against such Guarantor to perform its funding obligations under the Clearlake Equity Commitment Letter, in each case subject to (i) the limitations and conditions set forth in the Clearlake Equity Commitment Letter and (ii) the terms and conditions of the Merger Agreement.

The obligation of the Investors to provide the Preferred Equity Financing under the Preferred Equity Commitment Letter is subject to certain conditions, including, but not limited to, the following (subject to certain exceptions and qualifications as set forth in the Preferred Equity Commitment Letter):

The Investors’ commitments under the Preferred Equity Commitment Letter automatically terminate upon the earliest to occur of: (i) five business days after February 5, 2022 (as such date may be extended in accordance with the Merger Agreement as in effect on the date of the Preferred Equity Commitment Letter), (ii) the initial funding date of the Preferred Equity Financing under the Preferred Equity Commitment Letter, (iii) five business days following the termination of the Merger Agreement in accordance with its terms without the funding of the Preferred Equity Financing, and (iv) the consummation of the Merger without the funding of the preferred equity commitment.

Concurrently with the execution of the Merger Agreement, the Guarantors have entered into the Limited Guarantee, pursuant to which such Guarantors have agreed, on a several and not joint basis, to guarantee the payment and performance of such Guarantor’s respective percentage of Parent’s obligation to pay the Parent Termination Fee and enforcement expenses related to the Parent Termination Fee and reimburse and indemnify

Cornerstone with respect to certain expenses in connection with Parent’s Debt Financing. The Guarantors may assign some or all of their respective obligations under the Limited Guarantee to any of their respective affiliates, co-investment funds or, subject to certain conditions being met, other investors.

The guaranteed obligations of the Guarantors are subject to an aggregate cap in the amount of $322,000,000 and an individual cap applicable to each Guarantor equal to such Guarantor’s specified percentage share of the guaranteed obligations. The Limited Guarantee will terminate upon the earliest to occur of:

In connection with the execution of the Merger Agreement, the Signing Securityholders have entered into the Support Agreements.

As of the close of business on the Record Date, the Signing Stockholders held, in the aggregate, approximately 10,442,350 shares of common stock, representing approximately 15.6% of the outstanding shares of common stock entitled to vote at the Special Meeting. Under the Voting and Support Agreements, the Signing Stockholders have agreed to, during the term of such agreements, vote the Signing Stockholders’ shares of common stock (i) in favor of the adoption of the Merger Agreement and the approval of the Merger and the other transactions contemplated by the Merger Agreement;(ii) against any action or agreement which would result in a breach of any representation, warranty, covenant or obligation of Cornerstone in the Merger Agreement; and/or (iii) against any alternative acquisition proposals and any action which is intended, or would reasonably be expected, to impede, interfere with, delay, postpone, discourage or adversely affect the Merger. In addition, the Silver Lake Support Agreements require the Silver Lake Group (y) subject to limited exceptions, not to transfer or convert into common stock their Cornerstone Convertible Notes and (z) to support certain amendments to the Indenture to facilitate the consummation of the Merger and the financing relating thereto.

If the Merger is consummated and certain conditions are met, stockholders of the Company (i) who continuously hold shares of Cornerstone common stock through the Effective Time, (ii) who did not vote their shares in favor of the adoption of the Merger Agreement; (iii) who are entitled to demand appraisal rights under Section 262 of the DGCL, (iv) who otherwise properly comply with the applicable requirements and procedures of Section 262 of the DGCL; and (v) who do not thereafter withdraw their demand for appraisal of such shares, fail to perfect or otherwise lose their appraisal rights, in each case in accordance with Section 262 of the DGCL, will be entitled to demand appraisal of their shares and receive, in lieu of the Merger Consideration, an amount in cash equal to the “fair value” of their shares (as of the Effective Time, exclusive of any element of value arising from the accomplishment or expectation of the Merger, together with interest, if any), as determined by the Delaware Court, in accordance with Section 262 of the DGCL. Stockholders should be aware that the fair value of their shares could be more than, the same as or less than the Merger Consideration and that an investment banking opinion as to the fairness, from a financial point of view, of the consideration payable in a sale transaction, such as the Merger, is not an opinion as to, and does not otherwise address, fair value under Section 262 of the DGCL. Any stockholder contemplating the exercise of such appraisal rights should review carefully the provisions of Section 262 of the DGCL, particularly the procedural steps required to properly demand and perfect such rights.

The following is a summary of the procedures to be followed by stockholders that wish to exercise their appraisal rights under Section 262 of the DGCL, the full text of which is attached to this proxy as Annex D. This summary does not purport to be a complete statement of, and is qualified in its entirety by reference to, Section 262 of the DGCL. All references in Section 262 of the DGCL and in this summary to a “stockholder” are to the record holder of shares immediately prior to the Effective Time of the Merger as

to which appraisal rights are asserted. A person holding a beneficial interest in shares held of record in the name of another person, such as a broker or nominee, must act promptly to cause the stockholder of record to follow the steps summarized below properly and in a timely manner to perfect appraisal rights. Failure to follow any of the procedures of Section 262 of the DGCL may result in termination or waiver of appraisal rights under Section 262 of the DGCL. Stockholders should assume that the Company will take no action to perfect any appraisal rights of any stockholder.

Any stockholder who desires to exercise his, her or its appraisal rights should review carefully Section 262 of the DGCL and is urged to consult his, her or its legal advisor before electing or attempting to exercise such rights. The following summary does not constitute any legal or other advice nor does it constitute a recommendation that Company stockholders exercise appraisal rights under Section 262 of the DGCL.

Under Section 262 of the DGCL, where a merger is approved under Section 251(h), either a constituent corporation before the effective date of the merger, or the surviving corporation within 10 days thereafter, shall notify each of the stockholders of any class or series of stock of such constituent corporation who are entitled to appraisal rights of the approval of the merger or consolidation and that appraisal rights are available for any or all shares of such class or series of stock of such constituent corporation, and shall include in such notice a copy of Section 262. This proxy statement constitutes the formal notice of appraisal rights under Section 262 of the DGCL, and the required copy of Section 262 of the DGCL is attached to this proxy statement as Annex D. Any stockholder who wishes to exercise such appraisal rights or who wishes to preserve his, her or its right to do so should review the following discussion and Annex D carefully because failure to timely and properly comply with the procedures specified may result in the loss of appraisal rights under the DGCL.

If a stockholder elects to exercise appraisal rights under Section 262 of the DGCL, such stockholder must do all of the following:

Within 10 days after the Effective Time of the Merger, the Surviving Corporation will provide notice of the effective date of the Merger to those stockholders of the Company who have properly made a written demand for appraisal pursuant to the first bullet above, as required by Section 262 of the DGCL, has not voted in favor of the adoption of the Merger Agreement and has not withdrawn or otherwise lost the right to appraisal. If the Merger is consummated, a failure to make a written demand for appraisal in accordance with the time periods specified in the first bullet above (or to take any of the other steps specified in the above bullets) will be deemed to be a waiver or a termination of your appraisal rights. At any time within 60 days after the Effective Time of the Merger, any stockholder who has demanded an appraisal, but who has not commenced an appraisal proceeding or joined that proceeding as a named party, has the right to withdraw the demand and to accept the Merger Consideration, without interest, specified by the Merger Agreement for his, her or its shares. Any attempt to withdraw made more than 60 days after the Effective Time of the Merger will require the written approval of the Surviving Corporation and no appraisal proceeding before the Delaware Court as to any stockholder will be dismissed without the approval of the Delaware Court. Such approval may be conditioned upon any terms the Delaware Court deems just; provided, however, that this provision will not affect the right of any stockholder that has made an appraisal demand but who has not commenced an appraisal proceeding or joined such

proceeding as a named party to withdraw such stockholder’s demand for appraisal and to accept the terms offered in the Merger within 60 days after the Effective Time of the Merger. If the Surviving Corporation does not approve a stockholder’s request to withdraw a demand for appraisal when the approval is required or if the Delaware Court does not approve the dismissal of an appraisal proceeding, the stockholder would be entitled to receive only the appraised value determined in any such appraisal proceeding. This value could be higher or lower than, or the same as, the value of the per share Merger Consideration.

All written demands for appraisal should be addressed to the Company, 1601 Cloverfield Blvd., Suite 620 South Santa Monica, California 90404. Attention: General Counsel. The demand for appraisal must be executed by or for the stockholder of record, fully and correctly, as such stockholder’s name appears on the stockholder’s certificates (whether in book entry or on physical certificates) evidencing such stockholder’s shares. If the shares are owned of record in a fiduciary capacity, such as by a trustee, guardian or custodian, the demand should be made in that capacity, and if the shares are owned of record by more than one person, as in a joint tenancy or tenancy in common, the demand must be made by or for all owners of record. An authorized agent, including one or more joint owners, may execute the demand for appraisal for a stockholder of record, but such agent must identify the record owner or owners and expressly disclose in such demand that the agent is acting as agent for the record owner or owners of such shares.

A beneficial owner of shares held in “street name” who wishes to exercise appraisal rights should take such actions as may be necessary to ensure that a timely and proper demand for appraisal is made by the stockholder of record. If shares are held through a brokerage firm, bank or other nominee who in turn holds the shares through a central securities depository nominee, such as Cede & Co., a demand for appraisal of such shares must be made by or on behalf of the depository nominee, and must identify the depository nominee as the stockholder of record. Any beneficial owner who wishes to exercise appraisal rights and holds shares through a nominee holder is responsible for ensuring that the demand for appraisal is timely made by the stockholder of record. The beneficial holder of the shares should instruct the nominee holder that the demand for appraisal should be made by the stockholder of record of the shares, which may be a central securities depository nominee if the shares have been so deposited.

A record stockholder, such as a broker, bank, fiduciary, depository or other nominee, who holds shares as a nominee for several beneficial owners (may exercise appraisal rights with respect to the shares held for one or more beneficial owners while not exercising such rights with respect to the shares held for other beneficial owners. In such case, the written demand for appraisal must set forth the number of shares covered by such demand. Unless a demand for appraisal specifies a number of shares, such demand will be presumed to cover all shares held in the name of such stockholder.

Within 120 days after the effective date of the Merger, but not thereafter, the Surviving Corporation or any stockholder who has complied with Section 262 of the DGCL and is entitled to appraisal rights under Section 262 may commence an appraisal proceeding by filing a petition in the Delaware Court demanding a determination of the fair value of the shares held by all stockholders entitled to appraisal rights who did not vote their shares in favor of the Merger and properly demanded appraisal of such shares. If no such petition is filed within that 120-day period, appraisal rights will be lost for all stockholders who had previously demanded appraisal of their shares. The Company is under no obligation to and has no present intention to file a petition and stockholders should not assume that the Company will file a petition or that it will initiate any negotiations with respect to the fair value of the shares. Accordingly, it is the obligation of the stockholders to initiate all necessary action to perfect their appraisal rights in respect of the shares within the period prescribed in Section 262 of the DGCL.

Within 120 days after the effective date of the Merger, any stockholder who has complied with the requirements for exercise of appraisal rights will be entitled, upon written request, to receive from the Surviving Corporation a statement setting forth the aggregate number of shares not voted in favor of the adoption of the Merger Agreement and with respect to which Cornerstone has received demands for appraisal, and the aggregate number of stockholders of such shares. Such statement must be mailed within 10 days after a written request therefor has been received by the Surviving Corporation or within 10 days after the expiration of the period for

delivery of demands for appraisal, whichever is later. Notwithstanding the foregoing requirement that a demand for appraisal must be made by or on behalf of the record owner of the shares, a person who is the beneficial owner of shares held either in a voting trust or by a nominee on behalf of such person, and as to which demand has been properly made and not effectively withdrawn, may, in such person's own name, file a petition for appraisal or request from the Surviving Corporation the statement described in this paragraph.

If a petition for appraisal is duly filed by any stockholder and a copy of the petition is delivered to the Surviving Corporation, the Surviving Corporation will then be obligated within 20 days after receiving service of a copy of the petition to file with the Delaware Register in Chancery a duly verified list (the “Verified List”) containing the names and addresses of all stockholders who have demanded an appraisal for their shares (the “Dissenting Stockholders”) and with whom agreements as to the value of their shares has not been reached. Upon the filing of a petition by a Dissenting Stockholder, the Delaware Court may order a hearing and that notice of the time and place fixed for the hearing on the petition will be mailed to the Surviving Corporation and all the Dissenting Stockholders shown on the Verified List. Notice will also be published at least one week before the day of the hearing in a newspaper of general circulation published in the City of Wilmington, Delaware, or in another publication deemed advisable by the Delaware Court. The costs relating to these notices will be borne by the Surviving Corporation.

If a hearing on the petition is held, the Delaware Court is empowered to determine which Dissenting Stockholders have complied with the provisions of Section 262 of the DGCL and are entitled to an appraisal of their shares. The Delaware Court may require that Dissenting Stockholders submit their Share certificates, if any, to the Delaware Register in Chancery for notation thereon of the pendency of the appraisal proceedings. The Delaware Court is empowered to dismiss the proceedings as to any Dissenting Stockholder who does not comply with such requirement. Accordingly, Dissenting Stockholders are cautioned to retain their Share certificates after the Effective Time and thereafter comply with all orders of the Delaware Court in respect of such certificates. In addition, assuming the shares remain listed on a national securities exchange immediately before the Effective Time, which we expect to be the case, the Delaware Court is required to dismiss the appraisal proceedings as to all Dissenting Stockholders unless (i) the total number of shares entitled to appraisal exceeds 1% of the outstanding shares eligible for appraisal or (ii) the value of the consideration provided in the Merger for such total number of shares exceeds $1 million.

After the Delaware Court determines which stockholders are entitled to appraisal, the appraisal proceeding will be conducted in accordance with the rules of the Delaware Court, including any rules specifically governing appraisal proceedings. Through the appraisal proceeding, the Delaware Court will determine the fair value of the shares exclusive of any element of value arising from the accomplishment or expectation of the Merger, together with interest, if any, to be paid upon the amount determined to be the fair value. Unless the Delaware Court in its discretion determines otherwise for good cause shown, interest from the effective date of the Merger through the date of payment of the judgment will be compounded quarterly and will accrue at 5% over the Federal Reserve discount rate (including any surcharge) as established from time to time during the period between the Effective Time of the Merger and the date of payment of the judgment. However, at any time before the entry of judgment in the proceedings, the Surviving Corporation may pay to each stockholder entitled to appraisal an amount in cash, in which case interest will accrue thereafter only upon the sum of (i) the difference, if any, between the amount so paid by the Surviving Corporation and the fair value of the shares as determined by the Delaware Court, and (ii) interest accrued before such voluntary cash payment, unless paid at that time.

In determining fair value, the Delaware Court is to take into account all relevant factors. In Weinberger v. UOP, Inc., the Supreme Court of Delaware discussed the factors that could be considered in determining fair value in an appraisal proceeding, stating that “proof of value by any techniques or methods that are generally considered acceptable in the financial community and otherwise admissible in court” should be considered, and that “fair price obviously requires consideration of all relevant factors involving the value of a company.” The Delaware Supreme Court stated that, in making this determination of fair value, the Delaware Court must consider market value, asset value, dividends, earnings prospects, the nature of the enterprise and any other facts that could be ascertained as of the date of the merger that throw any light on future prospects of the merged corporation. In Weinberger, the Supreme Court of Delaware also stated that “elements of future value, including the nature of the enterprise, which are known or susceptible of proof as of the date of the merger and not the product of speculation, may be considered.” Section 262 of the DGCL provides that fair value is to be

“exclusive of any element of value arising from the accomplishment or expectation of the merger.” In Cede & Co. v. Technicolor, Inc., the Delaware Supreme Court stated that such exclusion is a “narrow exclusion that does not encompass known elements of value,” but which rather applies only to the speculative elements of value arising from such accomplishment or expectation. An opinion of an investment banking firm as to the fairness from a financial point of view of the consideration payable in a merger is not an opinion as to fair value under Section 262 of the DGCL. You should be aware that the fair value of your shares as determined under Section 262 of the DGCL could be more than, the same as, or less than the merger consideration that you would otherwise be entitled to receive under the terms of the Merger Agreement.

Upon application by the Surviving Corporation or by stockholder entitled to participate in the appraisal proceeding, the Delaware Court may, in its discretion, proceed to trial upon the appraisal prior to the final determination of the stockholders entitled to an appraisal. Any stockholder whose name appears on the Verified List and who has submitted such stockholder’s stock certificates, if any, to the Delaware Register in Chancery, if such is required, may participate fully in all proceedings until it is finally determined that such stockholder is not entitled to appraisal rights. When the fair value of the shares is determined, the Delaware Court will direct the payment of such value, with interest thereon, if any, to the stockholders entitled thereto, forthwith in the case of uncertificated stockholders or upon surrender by certificated stockholders of their stock certificates. The Delaware Court’s decree may be enforced as other decrees in the Delaware Court may be enforced. The Delaware Court may also (i) determine the costs of the proceeding (which do not include attorneys’ fees or the fees and expenses of experts) and tax such costs upon the parties as the Delaware Court deems equitable and (ii) upon application of a stockholder, order all or a portion of the expenses incurred by any Dissenting Stockholder in connection with the appraisal proceeding, including, without limitation, reasonable attorneys’ fees and fees and expenses of experts, to be charged pro rata against the value of all the shares entitled to appraisal. In the absence of such an order, each party bears its own expenses. Determinations by the Delaware Court are subject to appellate review by the Delaware Supreme Court.

Stockholders considering whether to seek appraisal should bear in mind that the fair value of their shares determined under Section 262 of the DGCL could be more than, the same as, or less than the value of the Merger Consideration to be paid in the Merger. Although the Company believes that the Merger Consideration is fair, no representation is made as to the outcome of the appraisal of fair value as determined by the Delaware Court. Neither Parent nor the Company anticipates offering more than the Merger Consideration to any Dissenting Stockholder, and each of Parent and the Company reserve the right to assert, in any appraisal proceeding, that for purposes of Section 262 of the DGCL, the “fair value” of the shares is less than the Merger Consideration.

The process of dissenting and exercising appraisal rights requires compliance with technical prerequisites. Stockholders wishing to exercise their appraisal rights should consult with their own legal counsel in connection with compliance with Section 262 of the DGCL.

Any stockholder who has duly demanded and perfected appraisal rights in compliance with Section 262 of the DGCL will not, after the Effective Time, be entitled to vote his or her shares for any purpose or be entitled to the payment of dividends or other distributions thereon, except dividends or other distributions payable to stockholders as of a date prior to the Effective Time.

If any stockholder who demands appraisal of shares under Section 262 of the DGCL fails to perfect, successfully withdraws or loses such stockholder’s right to appraisal, such stockholder’s shares will be deemed to have been converted at the Effective Time into the right to receive the Merger Consideration. A stockholder will fail to perfect, or effectively lose, the stockholder's right to appraisal if no petition for appraisal is filed within 120 days after the effective date of the Merger. Inasmuch as the Company has no obligation to file such a petition and has no present intention to do so, any stockholder who desires such a petition is advised to file it on a timely basis. In addition, a stockholder who has not commenced an appraisal proceeding or joined that proceeding as a named party may withdraw his, her or its demand for appraisal in accordance with Section 262 of the DGCL and accept the Merger Consideration by delivering to the Company a written withdrawal of such stockholder's demand for appraisal and acceptance of the terms of the Merger either within 60 days after the effective date of the Merger or thereafter with the written approval of the Company. Notwithstanding the foregoing, no appraisal proceeding in the Delaware Court will be dismissed as to any stockholder without the approval of the Delaware Court, and such approval may be conditioned upon such terms as the Delaware Court

deems just; provided, however, that the limitation set forth in this sentence will not affect the right of any stockholder who has not commenced an appraisal proceeding or joined that proceeding as a named party to withdraw such stockholder’s demand for appraisal and to accept the Merger Consideration within 60 days after the effective date of the Merger.

STOCKHOLDERS WHO VOTE SHARES IN FAVOR OF THE ADOPTION OF THE MERGER AGREEMENT WILL NOT BE ENTITLED TO EXERCISE APPRAISAL RIGHTS WITH RESPECT THERETO BUT, RATHER, WILL RECEIVE THE MERGER CONSIDERATION.

The foregoing summary of the rights of the stockholders of the Company to seek appraisal rights under Delaware law does not purport to be a complete statement of the procedures to be followed by the stockholders of the Company desiring to exercise any appraisal rights available thereunder and is qualified in its entirety by reference to Section 262 of the DGCL. The proper exercise of appraisal rights requires strict adherence to the applicable provisions of the DGCL. A copy of Section 262 of the DGCL is included as Annex D to this Proxy.

The Merger will be accounted for as a “purchase transaction” for financial accounting purposes.

The following discussion is a summary of material U.S. federal income tax consequences of the Merger that may be relevant to U.S. Holders and Non-U.S. Holders (each as defined below) of shares of common stock whose shares are converted into the right to receive cash pursuant to the Merger. This summary is general in nature and does not discuss all aspects of U.S. federal income taxation that may be relevant to a stockholder in light of its particular circumstances. In addition, this summary does not describe any tax consequences arising under the laws of any state, local or non-U.S. jurisdiction and does not consider any aspects of U.S. federal tax law other than income taxation. This discussion is based upon the Internal Revenue Code of 1986, as amended (the “Code”), Treasury Regulations promulgated under the Code, court decisions, published positions of the Internal Revenue Service (the “IRS”), and other applicable authorities, all as in effect on the date of this proxy statement and all of which are subject to change or differing interpretations at any time, possibly with retroactive effect. This discussion is limited to holders who hold their shares of common stock as “capital assets” within the meaning of Section 1221 of the Code (generally, property held for investment purposes).

This discussion is for general information only and does not address all of the tax consequences that may be relevant to holders in light of their particular circumstances. For example, this discussion does not address the tax consequences that may be relevant to holders who may be subject to special treatment under U.S. federal income tax laws, such as:

If a partnership (including an entity or arrangement, domestic or non-U.S., treated as a partnership for U.S. federal income tax purposes) is a beneficial owner of shares of common stock, then the tax treatment of a partner in such partnership will generally depend upon the status of the partner and the activities of the partner and the partnership. Partnerships holding shares of common stock and partners therein should consult their tax advisors regarding the consequences of the Merger.

We have not sought, and do not intend to seek, any ruling from the IRS with respect to the statements made and the conclusions reached in the following summary, and no assurance can be given that the IRS will agree with the views expressed herein, or that a court will not sustain any challenge by the IRS in the event of litigation.

THE FOLLOWING SUMMARY IS FOR GENERAL INFORMATIONAL PURPOSES ONLY AND IS NOT A SUBSTITUTE FOR CAREFUL TAX PLANNING AND ADVICE. WE URGE YOU TO CONSULT YOUR OWN TAX ADVISOR WITH RESPECT TO THE SPECIFIC TAX CONSEQUENCES TO YOU IN CONNECTION WITH THE MERGER IN LIGHT OF YOUR OWN PARTICULAR CIRCUMSTANCES, INCLUDING FEDERAL ESTATE, GIFT AND OTHER NON-INCOME TAX CONSEQUENCES, AND TAX CONSEQUENCES UNDER STATE, LOCAL OR NON-U.S. TAX LAWS.

For purposes of this discussion, a “U.S. Holder” is a beneficial owner of shares of common stock that is for U.S. federal income tax purposes:

The receipt of cash by a U.S. Holder in exchange for shares of common stock pursuant to the Merger will be a taxable transaction for U.S. federal income tax purposes. In general, such U.S. Holder’s gain or loss will be equal to the difference, if any, between the amount of cash received and the U.S. Holder’s adjusted tax basis in the shares surrendered pursuant to the Merger. Gain or loss must be determined separately for each block of shares (that is, shares acquired at the same cost in a single transaction). A U.S. Holder’s adjusted tax basis generally will equal the amount that such U.S. Holder paid for the shares. Such gain or loss will be capital gain

or loss and will be long-term capital gain or loss if such U.S. Holder’s holding period in such shares is more than one year at the time of the completion of the Merger. Long-term capital gains of non-corporate taxpayers are currently taxed at preferential U.S. federal income tax rates. The deductibility of capital losses is subject to limitations.

The following is a summary of the material U.S. federal income tax consequences that will apply to you if you are a Non-U.S. Holder. The term “Non-U.S. Holder” means a beneficial owner of common stock that is, for U.S. federal income tax purposes, not a U.S. Holder nor an entity classified as a partnership for U.S. federal income tax purposes.

Special rules, not discussed herein, may apply to certain Non-U.S. Holders, such as:

Any gain realized by a Non-U.S. Holder pursuant to the Merger generally will not be subject to U.S. federal income tax unless:

Information reporting and backup withholding (currently, at a rate of 24%) may apply to the proceeds received by a holder pursuant to the Merger. Backup withholding generally will not apply to (1) a U.S. Holder that furnishes a correct taxpayer identification number and certifies that such holder is not subject to backup withholding on IRS Form W-9 (or a substitute or successor form) or (2) a Non-U.S. Holder that (i) provides a certification of such holder’s foreign status on the appropriate series of IRS Form W-8 (or a substitute or successor form) or (ii) otherwise establishes an exemption from backup withholding. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules will be allowed as a refund or a credit against the holder’s U.S. federal income tax liability, provided that the required information is timely furnished to the IRS.

The foregoing summary does not discuss all aspects of U.S. federal income taxation that may be relevant to particular holders of common stock. Stockholders should consult their own tax advisors as to the particular tax consequences to them of exchanging their common stock for cash pursuant to the Merger under any federal, state, local or non-U.S. tax laws.

Sections 1471 through 1474 of the Code (“FATCA”), impose a U.S. federal withholding tax of 30% on certain payments made to a “foreign financial institution” (as specially defined under these rules) unless such institution enters into an agreement with the U.S. government to withhold on certain payments and to collect and provide to the U.S. tax authorities substantial information regarding certain U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with U.S. owners) or an exemption applies. FATCA also generally will impose a U.S. federal withholding tax of 30% on certain payments made to a non-financial foreign entity unless such entity provides the withholding agent a certification identifying certain direct and indirect U.S. owners of the entity or an exemption applies. An intergovernmental agreement between the United States and an applicable foreign country may modify these requirements. Under certain circumstances, a Non-U.S. Holder might be eligible for refunds or credits of such taxes. Subject to the proposed Treasury Regulations described below, FATCA will apply to gross proceeds from sales or other dispositions of common stock after December 31, 2018. The Treasury Department released proposed regulations which, if finalized in their present form, would eliminate the federal withholding tax of 30% applicable to the gross proceeds of a sale or other disposition common stock. In its preamble to such proposed regulations, the U.S. Treasury Department stated that taxpayers may generally rely on the proposed regulations until final regulations are issued.

Prospective investors are encouraged to consult with their own tax advisors regarding the possible implications of FATCA on the disposition of common stock pursuant to the Merger.

Cornerstone and Parent have agreed to use reasonable best efforts to obtain all regulatory approvals required to consummate the Merger and the other transactions contemplated by the Merger Agreement.

Under the HSR Act and the rules promulgated thereunder, certain acquisitions may not be completed until information has been furnished to the Antitrust Division of the U.S. Department of Justice (“DOJ”) and the Federal Trade Commission (“FTC”), and the applicable HSR Act waiting period requirements have been satisfied. The waiting period under the HSR Act is 30 calendar days, unless the waiting period is terminated earlier or extended. The Merger is subject to the provisions of the HSR Act and therefore cannot be completed until each of Cornerstone and Clearlake file a notification and report form with the DOJ and the FTC under the HSR Act and the applicable waiting period has expired or been terminated. Cornerstone and Clearlake made the necessary filings with the Antitrust Division of the DOJ and the FTC on August 19, 2021.

At any time before or after consummation of the Merger, notwithstanding the termination or expiration of the waiting period under the HSR Act, the DOJ or the FTC could take such action under the antitrust laws as it deems necessary or desirable in the public interest, including seeking to enjoin the completion of the Merger, seeking divestiture of substantial assets of the parties, or requiring the parties to license or hold separate assets or terminate existing relationships and contractual rights. At any time before or after the completion of the Merger, and notwithstanding the termination or expiration of the waiting period under the HSR Act, any state or foreign jurisdiction could take such action under the antitrust laws as it deems necessary or desirable in the public interest. Such action could include seeking to enjoin the completion of the Merger or seeking divestiture of substantial assets of the parties. Private parties may also seek to take legal action under the antitrust laws under certain circumstances. We cannot be certain that a challenge to the Merger will not be made or that, if a challenge is made, we will prevail.

German Arc imposes a pre-merger notification requirement on transactions that qualify as concentrations in the meaning of the law and meet certain specified turnover or transaction value thresholds, which the present

merger meets. Accordingly, consummation of the merger is conditional upon the merger being cleared by the FCO. Clearance is considered granted if, after a transaction has been notified, the applicable one-month waiting period expires without the decision by the FCO to open Phase II proceedings or if the FCO explicitly clears the transaction before the expiration of the waiting period. If the FCO initiates Phase II proceedings, clearance is granted by way of a formal decision, or, if the decision is not served upon the notifying undertakings within a period of five months from receipt of the complete notification, is deemed to be granted. Clearlake notified the FCO of the proposed transaction on August 23, 2021 and received clearance for the transaction from the FCO on September 3, 2021.

The Austrian Cartel Act imposes a pre-merger notification requirement on transactions that qualify as concentrations in the meaning of the law and meet certain specified turnover or transaction value thresholds, which the present merger meets. Accordingly, consummation of the merger requires notification of the merger to the Bundeswettbewerbsbehörde (Austrian Federal Competition Authority, “FCA”), Clearance is considered granted if, after a transaction has been notified, the applicable four week waiting period expires without the FCA or the Bundeskartellanwalt (Federal Cartel Prosecutor) applying to open Phase II proceedings, or if they waive the opening of Phase II proceedings prior to the expiry of that waiting period. If Phase II proceedings are initiated, clearance is granted by way of a formal decision of the Austrian Cartel Court, or, if the decision is not taken within a period of five months, is deemed to be granted. Clearlake notified the FCA of the proposed transaction on August 23, 2021.

One or more governmental agencies may impose a condition, restriction, qualification, requirement or limitation when it grants the necessary approvals and consents. Third parties may also seek to intervene in the regulatory process or litigate to enjoin or overturn regulatory approvals, any of which actions could significantly impede or even preclude obtaining required regulatory approvals. There is currently no way to predict how long it will take to obtain all of the required regulatory approvals or whether such approvals will ultimately be obtained and there may be a substantial period of time between the approval by stockholders and the completion of the Merger.

Although we expect that all required regulatory clearances and approvals will be obtained, we cannot assure you that these regulatory clearances and approvals will be timely obtained, obtained at all or that the granting of these regulatory clearances and approvals will not involve the imposition of additional conditions on the completion of the Merger, including the requirement to divest assets, or require changes to the terms of the Merger Agreement. These conditions or changes could result in the conditions to the Merger not being satisfied.

On September 1, 2021, Shiva Stein, a purported stockholder of Cornerstone, commenced an action in the United States District Court for the Southern District of New York against Cornerstone and the Board of Directors.On September 9, 2021, Alex Ciccotelli, a purported stockholder of Cornerstone, commenced an action in the United States District Court for the Southern District of New York against Cornerstone and the Board of Directors. The Stein Complaint and the Ciccotelli Complaint assert claims under Sections 14(a) and 20(a) of the Exchange Act and seek, among other things, an injunction preventing consummation of the proposed transaction with Clearlake, rescission of the proposed transaction or rescissory damages in the event it is consummated, an accounting by the defendants for all damages caused to the plaintiff, and the award of attorneys’ fees and expenses. The Ciccotelli Complaint also asserts a claim for declaratory relief. Defendants believe the claims asserted in the Stein Complaint and the Ciccotelli Complaint are without merit, deny any wrongdoing in connection with the filing of this proxy statement, and intend to vigorously defend against the claims.

The following summary describes the material provisions of the Merger Agreement. The descriptions of the Merger Agreement in this summary and elsewhere in this proxy statement are not complete and are qualified in their entirety by reference to the Merger Agreement, a copy of which is attached to this proxy statement as Annex A and incorporated into this proxy statement by reference. You should carefully read and consider the entire Merger Agreement, which is the legal document that governs the Merger, because this summary may not contain all the information about the Merger Agreement that is important to you. The rights and obligations of the parties are governed by the express terms of the Merger Agreement and not by this summary or any other information contained in this proxy statement.

The representations, warranties, covenants and agreements described below and included in the Merger Agreement (i) were made only for purposes of the Merger Agreement and as of specific dates; (ii) were made solely for the benefit of the parties to the Merger Agreement; and (iii) may be subject to important qualifications, limitations and supplemental information agreed to by Cornerstone, Parent and Merger Sub in connection with negotiating the terms of the Merger Agreement and contained in the confidential disclosure schedules. In addition, the representations and warranties have been included in the Merger Agreement for the purpose of allocating contractual risk between Cornerstone, Parent and Merger Sub rather than to establish matters as facts, and may be subject to standards of materiality applicable to such parties that differ from those applicable to investors. Stockholders are not third-party beneficiaries under the Merger Agreement and should not rely on the representations, warranties, covenants and agreements or any descriptions thereof as characterizations of the actual state of facts or condition of Cornerstone, Parent or Merger Sub or any of their respective affiliates or businesses. Moreover, information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement. In addition, you should not rely on the covenants in the Merger Agreement as actual limitations on the respective businesses of Cornerstone, Parent and Merger Sub, because the parties may take certain actions that are either expressly permitted in the confidential disclosure schedule to the Merger Agreement or as otherwise consented to by the appropriate party, which consent may be given without prior notice to the public. The Merger Agreement is described below, and included as Annex A, only to provide you with information regarding its terms and conditions, and not to provide any other factual information regarding Cornerstone, Parent, Merger Sub or their respective businesses. Accordingly, the representations, warranties, covenants and other agreements in the Merger Agreement should not be read alone, and you should read the information provided elsewhere in this document and in our filings with the SEC regarding Cornerstone and its business.

The Merger Agreement provides that, upon the terms and subject to the conditions of the Merger Agreement and in accordance with the DGCL, at the Effective Time: (i) Merger Sub will be merged with and into Cornerstone, with Cornerstone continuing as the Surviving Corporation; and (ii) the separate existence of Merger Sub will cease. From and after the Effective Time, all properties, rights, privileges, powers and franchises of Cornerstone and Merger Sub will become the properties, rights, privileges, powers and franchises of Cornerstone as the Surviving Corporation, and all of the debts, liabilities and duties of Cornerstone and Merger Sub will become the debts, liabilities and duties of Cornerstone as the Surviving Corporation.

At the Effective Time, the certificate of incorporation of Cornerstone as the Surviving Corporation will be amended and restated to conform to Exhibit B of the Merger Agreement and the bylaws of Cornerstone as the Surviving Corporation will be amended and restated to conform to Exhibit C of the Merger Agreement. Immediately after the Effective Time, the directors and officers of Cornerstone as the Surviving Corporation will be the respective individuals who were designated by Cornerstone, Parent and Merger Sub as the directors and officers in a schedule to the Merger Agreement.

The Closing of the Merger will take place no later than the third business day after the satisfaction or waiver of all of the closing conditions of the Merger (described below under the caption, “—Conditions to the Closing of the Merger”) (other than those conditions to be satisfied at the Closing of the Merger). However, if the Marketing Period (as defined in the Merger Agreement) has not yet concluded, then the Closing of the Merger will take place on the earlier of (i) any business day that is specified by Parent, as long as Parent

provides Cornerstone with at least two business days’ prior notice and (ii) one business day following the final day of the Marketing Period, in each case subject to the satisfaction or waiver of all of the closing conditions of the Merger (other than those conditions to be satisfied at the Closing of the Merger). On the Closing Date, the parties will file a certificate of merger with the Secretary of State of the State of Delaware in accordance with the DGCL. The Merger will become effective upon the date and time of the filing of the certificate of merger or such later date and time as is agreed upon in writing by the parties and specified in the certificate of merger.

At the Effective Time, and without any further action on the part of the parties or any Cornerstone stockholder, each share then outstanding immediately prior to the Effective Time (except for (i) shares held by Cornerstone (or held in Cornerstone’s treasury), (ii) shares held by Parent or any other direct or indirect subsidiary of Parent or any assigns thereof, and (iii) any Dissenting Shares) will be canceled and cease to exist and automatically converted into the right to receive cash in an amount equal to the Per Share Merger Consideration, subject to any withholding of taxes required by applicable law.

At the Effective Time, and without any further action on the part of the parties or the holders thereof, each Vested Company RSU, Vested Company Option and each Director RSU will be cancelled and automatically converted into the right to receive an amount in cash equal to the product of (i) the aggregate number of shares subject to, or issuable in settlement of, such award immediately prior to the Effective Time, multiplied by (ii) the Per Share Merger Consideration (or, for each Company Option, the excess, if any, of the Per Share Merger Consideration over such Company Option’s per share exercise price), subject to any required withholding of taxes.

At the Effective Time, and without any further action on the part of the parties or the holders thereof, each Unvested Award will be cancelled and automatically converted into the right to receive the Unvested Consideration Amount, which Unvested Consideration Amounts will be paid at the same time(s) that the Unvested Awards would have vested in accordance with their terms and will remain subject to the holder of the Unvested Awards remaining in continuous service with Parent, the Surviving Corporation or any of its Subsidiaries through each such vesting date (except, that any terms and conditions relating to accelerated vesting upon a termination of the holder’s employment in connection with or following the Merger will continue to apply to the Unvested Consideration Amount). For the avoidance of doubt, any Company Options (whether a Vested Company Option or an Unvested Company Option) with a per share exercise price equal to or greater than the Per Share Merger Consideration will be cancelled immediately upon the Effective Time without payment or consideration.

The Merger Agreement generally provides that after August 5, 2021, no new offering periods will begin under the Cornerstone ESPP, no Cornerstone employee may become new a participant in the Cornerstone ESPP and no Cornerstone ESPP participant may increase the percentage amount of his or her payroll deduction election. Furthermore, the last day of any offering periods for the Cornerstone ESPP still in effect at the Effective Time will be accelerated to occur prior to the Effective Time. Subject to the Closing of the Merger, the Cornerstone ESPP will terminate effective immediately prior to the Effective Time.

The Paying Agent will act as agent to Cornerstone stockholders to receive the Merger Consideration payments. At or prior to the Closing, Parent will deposit or cause to be deposited with the Paying Agent cash sufficient to pay the Merger Consideration to Cornerstone stockholders.

Promptly after the Effective Time (and in any event within three business days), the Surviving Corporation will mail or cause to be mailed to each holder of record of any shares entitled to receive the Merger Consideration a customary form of letter of transmittal and instructions for surrendering any certificates or book-entry shares in exchange for the Merger Consideration for each share formerly evidenced by such certificates or book-entry shares.

If any funds deposited with the Paying Agent is not claimed within 12 months after the Effective Time, the Surviving Corporation may require the Paying Agent to deliver such unclaimed funds to the Surviving Corporation, at which point, holders of shares entitled to the unclaimed funds may look to the Surviving Corporation (subject to abandoned property, escheat and other similar legal requirements) only as general creditors with respect to the Merger Consideration that may be payable upon due surrender of the certificates or book-entry shares held by such holders.

The Surviving Corporation, Parent and Merger Sub may deduct and withhold any applicable taxes.

The Merger Agreement contains representations and warranties of Cornerstone, Parent and Merger Sub.

Some of the representations and warranties in the Merger agreement made by Cornerstone are qualified as to “materiality” or “Material Adverse Effect.” For purposes of the Merger Agreement, an event, occurrence, violation, inaccuracy, circumstance or other matter (each, an “Effect”) is deemed to have a “Material Adverse Effect” on Cornerstone and its subsidiaries, taken as a whole, if such event, violation, inaccuracy, circumstance or other matter (whether or not any such matter, considered together with all other matters, would constitute a breach of the representations, warranties, covenants or agreements of Cornerstone set forth in the Merger Agreement), individually or in the aggregate, (i) has had or would reasonably be expected to have, individually or in the aggregate, a material adverse effect on the business, asset, financial condition or results of operations of Cornerstone and its subsidiaries, taken as a whole; or (ii) does or would reasonably be expected to prevent the consummation by the Company of the Transactions, except that, with respect to clause (i) only, none of the following, and no effect arising out of, relating to or resulting from the following, will be deemed in and of themselves, either alone or in combination, to constitute a Material Adverse Effect on Cornerstone and its subsidiaries, and none of the following will be taken into account in determining whether there is, or would reasonably likely to be, a Material Adverse Effect on Cornerstone and its subsidiaries:

In the Merger Agreement, Cornerstone has made customary representations and warranties to Parent and Merger Sub that are subject, in some cases, to specified exceptions and qualifications contained in the Merger Agreement. These representations and warranties relate to, among other things: