Item 3.01 Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On September 5, 2025, CompoSecure, Inc. (the “ Company” or “ CompoSecure”), acting pursuant to authorization from its Board of Directors, notified the Nasdaq Stock Market, LLC (“ Nasdaq”) of its determination to voluntarily withdraw the principal listing of the Company’s Class A Common Stock, par value $0.0001 per share (the “ Common Stock”), from Nasdaq and transfer the listing to the New York Stock Exchange (the “ NYSE”). The Company expects that the listing and trading of the Common Stock on Nasdaq will cease at the close of trading on September 22, 2025, and that the listing and trading of the Common Stock on the NYSE will commence at market open on September 23, 2025. The Common Stock has been approved for listing on the NYSE, where it will continue to trade under the stock symbol “ CMPO.” The listing of the Company’s redeemable warrants to purchase shares of Common Stock (the “ Warrants”) will not be transferred to NYSE, and are expected to continue their listing on Nasdaq.

Item 7.01 Regulation FD Disclosure. On September 8, 2025, the Company issued a press release announcing the anticipated transfer of the principal listing of the Common Stock to the NYSE. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference to this Item 7.01. The information contained in Item 7.01, including Exhibit 99.1, 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, and shall not be deemed to be incorporated by reference into any filing of the Company under the Exchange Act or the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. Cautionary Note Regarding Forward-Looking Statements

Item 9.01 Financial Statements and Exhibits (d) Exhibits Exhibit Description No. 99.1 Press release, dated September 8, 2025, issued by CompoSecure, Inc. ─────────────────────────────────────────────────────────────────────────────────────────────── 104 The cover page from this Current Report on Form 8-K, formatted in Inline XBRL. SIGNATURE 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. Date: September 8, 2025 COMPOSECURE, INC. By: / s/ Steven J. Feder Name: Steven J. Feder Title: General Counsel & Corporate Secretary