MEC (MEC) SVP Leuba exercises RSUs, new grant and tax withholding

Rhea-AI Filing Summary

Mayville Engineering Company, Inc. senior vice president Sean P. Leuba reported compensation-related equity activity involving restricted stock units and common stock on March 15, 2026. He exercised restricted stock units to acquire 11,909 shares of common stock at a conversion price of $0.00 per share.

To cover tax obligations, 5,277 common shares were disposed of at $16.67 per share through share withholding, rather than an open‑market sale. He also received a new grant of 13,498 restricted stock units, and held 18,473 common shares directly after the transactions. A stock option award remains outstanding for 21,552 underlying shares at an exercise price of $16.22 per share, expiring on February 28, 2033. Footnotes state the restricted stock units vest in equal annual installments across 2025–2029, and the options vest 50% on each of February 28, 2024 and February 28, 2025.

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)
03/15/2026

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	03/15/2026		M		7,263	A	$0	19,104	D
Common Stock	03/15/2026		M		4,646	A	$0	23,750	D
Common Stock	03/15/2026		F		5,277	D	$16.67	18,473	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	03/15/2026		M			7,263	(1)	(1)	Common Stock	7,263	$0	7,263	D
Restricted Stock Units	$0	03/15/2026		M			4,646	(2)	(2)	Common Stock	4,646	$0	9,292	D
Restricted Stock Units	$0	03/15/2026		A		13,498		(3)	(3)	Common Stock	13,498	$0	13,498	D
Stock Option (right to buy)	$16.22							(4)	02/28/2033	Common Stock	21,552		21,552	D

Explanation of Responses:

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

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

3. The restricted stock units will vest 1/3 on each of March 15, 2027, 2028 and 2029.

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

	/s/ Garrett F. Bishop, Attorney-in-Fact for Sean P. Leuba	03/17/2026
	** 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 equity transactions did MEC executive Sean P. Leuba report?

Sean P. Leuba reported exercising restricted stock units into 11,909 common shares, receiving a new grant of 13,498 restricted stock units, and a tax-related share withholding of 5,277 common shares. These actions are part of his equity compensation at Mayville Engineering Company (MEC).

How many Mayville Engineering (MEC) shares does Sean P. Leuba hold after this Form 4?

Following these transactions, Sean P. Leuba directly holds 18,473 shares of MEC common stock. This total reflects RSU exercises into common shares and the tax-withholding disposition reported, giving investors a clearer picture of his current direct equity position in the company.

Were any of Sean P. Leuba’s MEC transactions open-market stock sales or purchases?

The reported activity does not include open-market purchases or sales. Instead, it reflects RSU exercises, a new RSU grant, and a tax-withholding disposition of 5,277 common shares, where shares were withheld to satisfy tax obligations rather than sold in the market.

What new restricted stock unit awards did Sean P. Leuba receive from MEC?

Sean P. Leuba received a new grant of 13,498 restricted stock units. Footnotes state different RSU awards will vest in three equal annual installments on March 15 of the years 2025–2029, aligning vesting with continued service at Mayville Engineering Company.

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

He holds a stock option described as a right to buy MEC common stock with 21,552 underlying shares at an exercise price of $16.22 per share. According to the disclosure, this option expires on February 28, 2033 and vests 50% on each of two prior vesting dates.

How are Sean P. Leuba’s MEC restricted stock units scheduled to vest?

Footnotes explain that certain restricted stock units will vest in three equal annual installments on March 15 of 2025, 2026, and 2027; others on 2026–2028 and 2027–2029. This staggered schedule ties equity vesting to longer-term employment with MEC.