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Mayville Engineering Company, Inc._March 3, 2026 0001766368false00017663682026-03-032026-03-03 ​ ​

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 3, 2026

Mayville Engineering Company, Inc. (Exact name of registrant as specified in its charter)

Wisconsin

001-38894

39-0944729

(State or other jurisdiction of incorporation)

(Commission File Number)

(IRS Employer Identification No.)

​ 135 S. 84th Street, Suite 300 Milwaukee, Wisconsin 53214 (Address of principal executive offices, including zip code) (414) 381-2860 (Registrant’s telephone number, including area code)

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, no par value

MEC

New York Stock Exchange

​ 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 3, 2026, Mayville Engineering Company, Inc. issued a press release announcing financial results for its three and twelve months ended December 31, 2025. A copy of such press release is furnished as Exhibit 99 to this Current Report on Form 8-K and is incorporated by reference herein. Item 9.01. Financial Statements and Exhibits. (a)Not applicable. (b)Not applicable. (c)Not applicable. (d)Exhibits. The exhibit listed in the exhibit index below is being furnished herewith.

EXHIBIT INDEX

Exhibit Number ​ ​ ​

99 ​ Press Release of Mayville Engineering Company, Inc., dated March 3, 2026 regarding financial results for its three and twelve months ended December 31, 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. ​

MAYVILLE ENGINEERING COMPANY, INC.

​ ​ ​

Date: March 3, 2026 By: /s/ Rachele M. Lehr

​ ​ Rachele M. Lehr

​ ​ Chief Financial Officer

​ ​ ​

Mayville Engineering Company, Inc._November 4, 2025 0001766368false00017663682025-11-042025-11-04 ​ ​

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): November 4, 2025

Mayville Engineering Company, Inc. (Exact name of registrant as specified in its charter)

Wisconsin

001-38894

39-0944729

(State or other jurisdiction of incorporation)

(Commission File Number)

(IRS Employer Identification No.)

​ 135 S. 84th Street, Suite 300 Milwaukee, Wisconsin 53214 (Address of principal executive offices, including zip code) (414) 381-2860 (Registrant’s telephone number, including area code)

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, no par value

MEC

New York Stock Exchange

​ 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 November 4, 2025, Mayville Engineering Company, Inc. issued a press release announcing financial results for its third quarter ended September 30, 2025. A copy of such press release is furnished as Exhibit 99 to this Current Report on Form 8-K and is incorporated by reference herein. Item 9.01. Financial Statements and Exhibits. (a)Not applicable. (b)Not applicable. (c)Not applicable. (d)Exhibits. The exhibit listed in the exhibit index below is being furnished herewith.

EXHIBIT INDEX

Exhibit Number

99 ​ Press Release of Mayville Engineering Company, Inc., dated November 4, 2025 regarding financial results for its third quarter ended September 30, 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. ​

MAYVILLE ENGINEERING COMPANY, INC.

​ ​ ​

Date: November 4, 2025 By: /s/ Rachele M. Lehr

​ ​ Rachele M. Lehr

​ ​ Chief Financial Officer

​ ​ ​