Exhibit 16.1
| GRANT THORNTON LLP | January 12, 2026 | ||
| 757 Third Ave., 9th Floor | |||
| New York, NY 10017 | |||
| D +1 212 599 0100 | U.S. Securities and Exchange Commission | ||
| F +1 212 370 4520 | Office of the Chief Accountant | ||
| 100 F Street, NE | |||
| Washington, DC 20549 | |||
| RE: | CompoSecure, Inc. | ||
| File No. 001-39687 | |||
| Dear Sir or Madam: | |||
| We have read Item 4.01 of Form 8-K of CompoSecure, Inc. dated January 12, 2026, and agree with the statements concerning our Firm contained therein. | |||
| Very truly yours, | |||
 | |||
| GT.COM | Grant Thornton LLP is a U.S. member firm of Grant Thornton International Ltd (GTIL). GTIL and each of its member firms are separate legal entities and are not a worldwide partnership. | ||