Results of Operations

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): July 23, 2025   ACME UNITED CORPORATION (Exact name of registrant as specified in its charter)     Connecticut 001-07698 06-0236700 (State or other jurisdiction of incorporation or organization) (Commission file number) (I.R.S. Employer Identification No.) 1 Waterview Dr , Shelton , Connecticut   06484 (Address of principal executive offices)   (Zip Code) Registrant’s telephone number, including area code: ( 203 ) 254-6060 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:     ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)   ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)   ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))   ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act:   Title of each class   Trading Symbol(s)   Name of each exchange on which registered Common Stock, $2.50 par value per share   ACU   NYSE American   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 July 23, 2025, Acme United Corporation (the “Company”) issued a press release announcing its financial results for the quarter ended June 30, 2025. A copy of the press release is attached as Exhibit 99.1 to this current report. ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS. (c) Exhibits   Exhibit Number Description 99.1 Press release dated July 23, 2025. 104   Cover Page Interactive Data File (embedded within the Inline XBRL document).   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.   ACME UNITED CORPORATION   By /s/ Walter C. Johnsen Walter C. Johnsen Chairman and Chief Executive Officer Dated: July 23, 2025 By /s/ Paul G. Driscoll Paul G. Driscoll Vice President and Chief Financial Officer Dated: July 23, 2025