Wisconsin	39-0944729
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

715 South Street Mayville, Wisconsin	53050
(Address of principal executive offices)	(Zip Code)

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 if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☒

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer	☐	Accelerated filer	☒
Non-accelerated filer	☐	Smaller reporting company	☒
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. ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262 (b)) by the registered public accounting firm that prepared or issued its audit report. ☐

The aggregate market value of the Common Stock held by non-affiliates of the Registrant, based on the closing price of the shares of common stock on the New York Stock Exchange on June 30, 2020, was $153,276,957.

The number of shares of the Registrant’s Common Stock outstanding as of February 15, 2021 was 20,059,390.

Part III of this report incorporates information by reference to the Registrant’s proxy statement for its 2021 annual meeting of shareholders, which proxy statement will be filed with the Securities and Exchange Commission no later than 120 days after the close of the year ended December 31, 2020.

Mayville Engineering Company, Inc. is filing this Amendment No. 12 to its Annual Report on Form 10-K for the fiscal year ended December 31, 2020, as filed with the Securities and Exchange Commission on March 5, 2021, solely to revise the certifications filed as Exhibits 31.1 and 31.2 to the original Form 10-K, which inadvertently omitted certain language regarding internal control over financial reporting required to be included in paragraph 4.4, and the certifications filed as Exhibits 31.1 and 31.2 to Amendment No. 1 to the Form 10-K filed on May 3, 2021. This Form 10-K/A does not reflect events occurring after the filing of the original Form 10-K and, other than the filing of the corrected certifications mentioned above, does not modify or update the disclosures in the original Form 10-K in any way.

No financial statements or schedules are filed as part of this Amendment No. 12 to Annual Report on Form 10-K/A.

The exhibits listed in the exhibit index below are filed with this Amendment No. 12 to Annual Report on Form 10-K/A.

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this Amendment No. 12 to Report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: May 3,14, 2021	By:	/s/ Robert D. Kamphuis
		Robert D. Kamphuis
		Chairman, President & Chief Executive Officer

	By:	/s/ Todd M. Butz
		Todd M. Butz
		Chief Financial Officer

Exhibit Number		Description

31.1		Certification of Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2		Certification of Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.