MEC (MEC) SVP Leuba buys 500 Mayville Engineering shares at $13.56

Rhea-AI Filing Summary

Mayville Engineering Company, Inc. senior vice president Sean P. Leuba reported an open-market purchase of common stock. On August 11, 2025, he indirectly bought 500 shares of common stock at $13.56 per share through an ESOP and/or 401(k) plan, bringing that indirect plan holding to 2,500 shares.

In addition, he holds directly 18,539 shares of common stock, 14,526 restricted stock units that vest in thirds on March 15 of 2025, 2026, and 2027, and 13,938 restricted stock units that vest in thirds on March 15 of 2026, 2027, and 2028. He also holds stock options for 21,552 shares at an exercise price of $16.22, vesting 50% on February 28, 2024 and 50% on February 28, 2025.

Insider Trade Summary

Net Buyer: 500 shares ($6,780)

Net Buy 5 txns

Insider Leuba Sean P

Role SVP, Corp. Development & GC

Bought 500 shs ($7K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	500	$13.56	$7K
holding	Restricted Stock Units	--	--	--
holding	Restricted Stock Units	--	--	--
holding	Stock Option (right to buy)	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 2,500 shares (Indirect, by ESOP and/or 401(k) Plan); Restricted Stock Units — 14,526 shares (Direct); Stock Option (right to buy) — 21,552 shares (Direct); Common Stock — 18,539 shares (Direct)

Footnotes (1)

1. Reflects the most recent ESOP and 401(k) balance. The restricted stock units will vest 1/3 on each of March 15, 2025, 2026 and 2027. The restricted stock units will vest 1/3 on each of March 15, 2026, 2027 and 2028. The options will vest 50% on each of February 28, 2024 and February 28, 2025.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Leuba Sean P

(Last) (First) (Middle)

135 SOUTH 84TH STREET

SUITE 300

(Street)

MILWAUKEE WI 53214

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Mayville Engineering Company, Inc. [ MEC ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SVP, Corp. Development & GC

3. Date of Earliest Transaction (Month/Day/Year)
08/11/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/11/2025		P		500	A	$13.56	2,500(1)	I	by ESOP and/or 401(k) Plan
Common Stock								18,539	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	$0							(2)	(2)	Common Stock	14,526		14,526	D
Restricted Stock Units	$0							(3)	(3)	Common Stock	13,938		13,938	D
Stock Option (right to buy)	$16.22							(4)	02/28/2033	Common Stock	21,552		21,552	D

Explanation of Responses:

1. Reflects the most recent ESOP and 401(k) balance.

2. The restricted stock units will vest 1/3 on each of March 15, 2025, 2026 and 2027.

3. The restricted stock units will vest 1/3 on each of March 15, 2026, 2027 and 2028.

4. The options will vest 50% on each of February 28, 2024 and February 28, 2025.

	/s/ Russell E. Ryba, Attorney-in-Fact for Sean P. Leuba	08/11/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did MEC executive Sean P. Leuba report?

Sean P. Leuba reported buying 500 MEC common shares. The purchase occurred on August 11, 2025 at $13.56 per share, increasing his ESOP and/or 401(k) plan holding to 2,500 shares while leaving separately reported direct holdings unchanged.

At what price did Sean P. Leuba acquire Mayville Engineering (MEC) shares?

He acquired MEC shares at $13.56 per share. The Form 4 shows an open-market purchase of 500 common shares on August 11, 2025, through an ESOP and/or 401(k) plan at that price, updating his indirect retirement-plan holdings.

How many MEC shares does Sean P. Leuba hold after the reported transaction?

He indirectly holds 2,500 MEC common shares through an ESOP and/or 401(k) plan. Separately, the filing lists 18,539 directly held common shares plus multiple grants of restricted stock units and stock options representing additional potential common shares.

What restricted stock units in MEC does Sean P. Leuba hold and how do they vest?

He holds 14,526 restricted stock units vesting in thirds on March 15 of 2025, 2026, and 2027. He also holds 13,938 restricted stock units vesting in thirds on March 15 of 2026, 2027, and 2028, all settling in MEC common stock upon vesting.

What stock options in Mayville Engineering (MEC) does Sean P. Leuba own?

He holds options to buy 21,552 MEC common shares at an exercise price of $16.22. These options vest 50% on February 28, 2024 and 50% on February 28, 2025, after which they remain exercisable until their stated expiration date.

Is Sean P. Leuba’s MEC share purchase held directly or indirectly?

The 500-share MEC purchase is reported as indirectly owned. The filing notes ownership is “by ESOP and/or 401(k) Plan,” meaning the shares are held within an employee benefit or retirement plan rather than as directly registered holdings in his own name.