Filed Pursuant to Rule 424(b)(3)

Registration No. 333-267200

PROSPECTUS SUPPLEMENT NO. 4

(To Prospectus dated October 7, 2022)

Up To 16,213,419 Shares Of Common Stock

Issuable Upon Exercise Of Warrants

Up To 120,443,882 Shares of Common Stock

Up To 7,588,430 Warrants

This prospectus supplement is being filed to update and supplement the information contained in the prospectus, dated October 7, 2022 (the “Prospectus”), with certain information contained in Exhibit 99.1 related to Item 2.02 in our Current Report on Form 8-K, furnished to the Securities and Exchange Commission on March 14, 2023, which is set forth below. Accordingly, we have attached the Current Report on Form 8-K to this prospectus supplement. The information from Exhibit 99.1 included in the Prospectus is limited to: the headings “Fourth Quarter Fiscal Year 2023 Financial Highlights” and “Recent Highlights” and the bullets directly thereunder; the final paragraph included under the heading “Financial Outlook”; the heading “Use of Non-GAAP Financial Measures and Key Business Measures” and the paragraphs directly thereunder, including the explanations of our Non-GAAP financial measures and Key Business Measures; and the financial tables presenting the preliminary, unaudited consolidated statement of operations, consolidated balance sheet, consolidated statement of cash flows, and Non-GAAP financial measures and reconciliation to GAAP results. No other information included in Exhibit 99.1 or in the Current Report on Form 8-K furnished to the Securities and Exchange Commission on March 14, 2023, is included in the Prospectus.

The Prospectus and this prospectus supplement relate to the issuance by us of up to an aggregate of 16,213,419 shares of our common stock, par value $0.0001 per share (the “Common Stock”) consisting of (i) up to 5,450,000 shares of Common Stock that are issuable upon the exercise of 5,450,000 warrants (the “Sponsor Warrants”) originally issued to JAR Sponsor, LLC (the “Sponsor”) in private placements at a price of $1.00 per warrant in connection with the initial public offering (the “L&F IPO”) of L&F Acquisition Corp., a Cayman Islands exempted company, (ii) up to 2,138,430 shares of Common Stock that are issuable upon the exercise of 2,138,430 warrants (together with the Sponsor Warrants, the “Private Placement Warrants”) originally issued to Jefferies LLC, the underwriter of the L&F IPO, in private placements at a price of approximately $1.21 per warrant in connection with the L&F IPO, and (iii) up to 8,624,989 shares of Common Stock that are issuable upon the exercise of 8,624,989 warrants (the “Public Warrants” and, together with the Private Placement Warrants, the “Warrants”) originally issued in the L&F IPO. Each Warrant entitles the holder thereof to purchase one share of our Common Stock at a price of $11.50 per share.

The Prospectus and this prospectus supplement also relate to the offer and sale from time to time by the selling securityholders named in the Prospectus or their permitted transferees (the “Selling Securityholders”) of (a) up to 120,443,882 shares of Common Stock consisting of (i) 89,348,952 shares of Common Stock issued as merger consideration to certain former stockholders of ZeroFox, Inc. and ID Experts Holdings, Inc., a Delaware corporation in connection with the consummation of the Business Combination (as defined in the Prospectus) based upon an implied equity consideration value of $10.00 per share, (ii) 193,039 shares of Common Stock issued upon the exercise by two of our executives of options assumed by us in connection with the consummation of the Business Combination at exercise prices of $0.49 per share and $0.60 per share, (iii) up to 137,253 shares of Common Stock issuable upon the exercise of options assumed by us in connection with the consummation of the Business

Combination with a weighted average exercise price of $0.29 per share, (iv) 2,000,000 shares of Common Stock issued by us to certain investors in connection with the consummation of the Business Combination in a private placement at a price of $10.00 per share, (v) up to 16,863,708 shares of Common Stock that are issuable upon the conversion of $150 million aggregate principal amount of our 7.00%/8.75% Convertible Senior Cash/PIK Toggle Notes due 2025 (the “Notes”) issued by us to certain investors in connection with the consummation of the Business Combination in a private placement for an aggregate purchase price of $150 million, (vi) 4,312,500 shares of Common Stock originally purchased by the Sponsor for $25,000, or approximately $0.006 per share, in a private placement in connection with the L&F IPO, and (vii) up to 7,588,430 shares of Common Stock issuable upon the exercise of the Private Placement Warrants, and (b) up to 7,588,430 Private Placement Warrants. The Notes have an initial conversion price of $11.50 per share, subject to adjustment as provided in the indenture governing the Notes. The number of shares issuable upon conversion of the Notes is calculated assuming that we exercise our option to pay interest in kind with respect to the Notes and further assumes conversion of the Notes after all interest payments prior to maturity are paid in kind and the Notes are converted and settled on the second business day prior to maturity. We will not receive any proceeds from the sale of shares of Common Stock or Warrants by the Selling Securityholders pursuant to the Prospectus.

This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectus supplement is qualified by reference to the Prospectus, including any amendments or supplements thereto, except to the extent that the information in this prospectus supplement updates and supersedes the information contained therein.

Our Common Stock is listed on The Nasdaq Global Market and our Public Warrants are listed on The Nasdaq Capital Market under the symbols “ZFOX” and “ZFOXW,” respectively. On March 13, 2023, the last reported sales price of our Common Stock was $2.26 per share and the last reported sales price of our Public Warrants was $0.10 per Warrant.

We are an “emerging growth company” as defined in Section 2(a) of the Securities Act of 1933, as amended, and are subject to reduced public company reporting requirements. The Prospectus and this prospectus supplement comply with the requirements that apply to an issuer that is an emerging growth company.

See the section titled “Risk Factors” beginning on page 8 of the Prospectus to read about factors you should consider before buying our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under the Prospectus or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is March 14, 2023.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 14, 2023

ZeroFox Holdings, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: (855) 936-9369

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition.

On March 14, 2023, ZeroFox Holdings, Inc. (the "Company") issued a press release announcing its financial results for the fourth quarter ending January 31, 2023. A copy of the press release is furnished herewith as Exhibit 99.1.

The information contained in this Item 2.02 and Item 9.01 in this Current Report on Form 8-K, including the accompanying Exhibit 99.1 hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filings, unless expressly incorporated by specific reference in such filing

Item 9.01 Financial Statements and Exhibits.

(d)Exhibits:

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.