MEC · Mayville Engineering Company, Inc. · Shareholders & Ownership

$14.45 +0.56 (+4.03%)

Russell 2000 member Rebalance outlook locked

Market Cap

$354.20M

25.50M

Volume · Oct 21 481.01K Avg daily vol (3M) 559.98K

Every disclosed holder of MEC in one list: 13F institutions, Schedule 13D and 13G filers, insiders (Forms 3, 4 and 5) and registered funds, each from its own latest filing. Holders nest by CIK and SEC reporting links, never by name, and each is summed once.

How the holder list picks a filing →

Who Owns MEC

13F quarter Sep 30, 2026, combined view: filers that have not filed yet carry their Jun 30, 2026 positions

Holder group	Holders	Shares	% Out	Summed
Institutional (13F)	151	21,163,049	82.99%	Yes
Insiders (Forms 3, 4, 5)	13	887,354	3.48%	Yes
13D/G-only blocks	1	995,756	3.90%	Yes
Remaining	—	2,454,172	9.62%	Rest
Registered funds (N-PORT, not summed)	159	7,534,530	29.55%	No

Shares outstanding: 25,500,331, the issuer's latest cover-page count restated onto today's split basis.

13D/G-only counts each filer's latest 13D or 13G that no 13F report of the listing contains, that names no 13F filer and that no counted insider files. Funds are never summed: their shares sit inside their advisers' 13F reports.

Holders of MEC

One row per holder Every filing By ultimate parent

All 13F Funds Insiders 13D/G Non-US

#	Holder	Shares	% Out	Change	As of	Notes
1	Portolan Capital Management, LLC 13F CIK 1350290 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,299,256	5.10%	+478,120	Jun 30, 2026	carried, not yet filed for the newest quarter
2	FMR LLC 13F CIK 315066 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	1,280,170	5.02%	+1,275,909	Jun 30, 2026	carried, not yet filed for the newest quarter
2.1	FMR LLC 13G CIK 315066 · Holding company · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	1,280,170	5.02%	—	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
2.2	Strategic Advisers U.S. Total Stock Fund Fund S000084926 · Registered fund · May 31, 2026 Fidelity Rutland Square Trust II, not summed	896,568	3.52%	+356,762	May 31, 2026	Fidelity Rutland Square Trust II, not summed
2.3	Fidelity Small Cap Index Fund Fund S000033638 · Registered fund · Jul 31, 2026 Fidelity Salem Street Trust, not summed	159,947	0.63%	+30,292	Jul 31, 2026	Fidelity Salem Street Trust, not summed
2.4	Fidelity Extended Market Index Fund Fund S000006021 · Registered fund · May 31, 2026 Fidelity Concord Street Trust, not summed	75,487	0.30%	-720	May 31, 2026	Fidelity Concord Street Trust, not summed
2.5	Fidelity Total Market Index Fund Fund S000006026 · Registered fund · May 31, 2026 Fidelity Concord Street Trust, not summed	27,029	0.11%	0	May 31, 2026	Fidelity Concord Street Trust, not summed
3	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	1,183,443	4.64%	+301,589	Jun 30, 2026	carried, not yet filed for the newest quarter
3.1	iShares Russell 2000 ETF Fund S000004344 · Registered fund · Jun 30, 2026 iShares Trust, not summed	376,136	1.48%	+49,245	Jun 30, 2026	iShares Trust, not summed
3.2	iShares Russell 2000 Value ETF Fund S000004342 · Registered fund · Jun 30, 2026 iShares Trust, not summed	142,836	0.56%	+41,421	Jun 30, 2026	iShares Trust, not summed
3.3	iShares Micro-Cap ETF Fund S000004439 · Registered fund · Jun 30, 2026 iShares Trust, not summed	49,230	0.19%	+16,285	Jun 30, 2026	iShares Trust, not summed
3.4	iShares US Small Cap Value Factor ETF Fund S000069740 · Registered fund · Jun 30, 2026 iShares Trust, not summed	33,394	0.13%	—	Jun 30, 2026	iShares Trust, not summed
3.5	Master Small Cap Index Series Fund S000002716 · Registered fund · Jun 30, 2026 Quantitative Master Series LLC, not summed	27,375	0.11%	+4,380	Jun 30, 2026	Quantitative Master Series LLC, not summed
4	Allspring Global Investments Holdings, LLC 13F CIK 1890906 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	1,072,916	4.21%	-927,434	Jun 30, 2026	carried, not yet filed for the newest quarter
4.1	Allspring Global Investments Holdings, LLC 13G CIK 1890906 · Holding company · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	1,072,916	4.21%	-979,697	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
4.2	Allspring Special Small Cap Value Fund Fund S000029108 · Registered fund · Jun 30, 2026 ALLSPRING FUNDS TRUST, not summed	715,687	2.81%	-615,444	Jun 30, 2026	ALLSPRING FUNDS TRUST, not summed
4.3	Allspring Special Global Small Cap Fund Fund S000029113 · Registered fund · Jul 31, 2026 ALLSPRING FUNDS TRUST, not summed	13,798	0.05%	-4,869	Jul 31, 2026	ALLSPRING FUNDS TRUST, not summed
5	Mikhail Stiskin 13G CIK 2058477 · Unknown · Oct 27, 2025 Rule 13d-1(c), passive investor	995,756	3.90%	—	Oct 27, 2025	Rule 13d-1(c), passive investor
6	Driehaus Capital Management LLC 13F CIK 938206 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	846,354	3.32%	+846,354	Jun 30, 2026	carried, not yet filed for the newest quarter
6.1	Driehaus Micro Cap Growth Fund Fund S000042829 · Registered fund · Jun 30, 2026 Driehaus Mutual Funds, not summed	133,251	0.52%	—	Jun 30, 2026	Driehaus Mutual Funds, not summed
7	SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC 13F CIK 1638555 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	800,000	3.14%	+800,000	Jun 30, 2026	carried, not yet filed for the newest quarter
8	DIMENSIONAL FUND ADVISORS LP 13F CIK 354204 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	782,276	3.07%	-143,940	Jun 30, 2026	carried, not yet filed for the newest quarter
8.1	Dimensional U.S. Targeted Value ETF Fund S000070901 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	99,388	0.39%	-36,427	Jul 31, 2026	Dimensional ETF Trust, not summed
8.2	U.S. Targeted Value Portfolio Fund S000000970 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	83,760	0.33%	-64,704	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
8.3	Dimensional U.S. Small Cap ETF Fund S000070906 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	68,923	0.27%	+2,036	Jul 31, 2026	Dimensional ETF Trust, not summed
8.4	U.S. MICRO CAP PORTFOLIO Fund S000000948 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	64,218	0.25%	+18,698	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
8.5	U.S. SMALL CAP PORTFOLIO Fund S000000971 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	55,052	0.22%	0	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
9	ROYCE & ASSOCIATES LP 13F CIK 906304 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	752,083	2.95%	+1,082	Jun 30, 2026	carried, not yet filed for the newest quarter
9.1	Royce Small-Cap Opportunity Fund Fund S000009512 · Registered fund · Jun 30, 2026 ROYCE FUND, not summed	354,768	1.39%	-31,808	Jun 30, 2026	ROYCE FUND, not summed
10	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	743,621	2.92%	+148,683	Jun 30, 2026	carried, not yet filed for the newest quarter
11	Boston Partners 13F CIK 1386060 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	696,429	2.73%	+463,792	Jun 30, 2026	carried, not yet filed for the newest quarter
12	Jupiter Topco LLC 13F CIK 2146052 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	575,278	2.26%	+575,278	Jun 30, 2026	carried, not yet filed for the newest quarter
13	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	556,284	2.18%	+141,138	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
14	BLAIR WILLIAM & CO/IL 13F CIK 902367 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	546,714	2.14%	-18,586	Jun 30, 2026	carried, not yet filed for the newest quarter
15	WELLINGTON MANAGEMENT GROUP LLP 13F CIK 902219 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	477,583	1.87%	+477,583	Jun 30, 2026	carried, not yet filed for the newest quarter
16	Janus Henderson Venture Fund Fund S000010488 · Registered fund · Jun 30, 2026 Janus Investment Fund, not summed	474,694	1.86%	—	Jun 30, 2026	Janus Investment Fund, not summed
17	EVR Research LP 13F CIK 1843019 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	441,908	1.73%	-178,092	Jun 30, 2026	carried, not yet filed for the newest quarter
18	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	374,578	1.47%	+38,743	Jun 30, 2026	carried, not yet filed for the newest quarter
19	First Eagle Investment Management, LLC 13F CIK 1325447 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	369,575	1.45%	-34,500	Jun 30, 2026	carried, not yet filed for the newest quarter
19.1	First Eagle Small Cap Opportunity Fund Fund S000072438 · Registered fund · Jul 31, 2026 First Eagle Funds, not summed	258,216	1.01%	-100,296	Jul 31, 2026	First Eagle Funds, not summed
20	JANE STREET GROUP, LLC 13F CIK 1595888 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	356,151	1.40%	+356,151	Jun 30, 2026	carried, not yet filed for the newest quarter
21	JPMORGAN CHASE & CO 13F CIK 19617 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	347,224	1.36%	+341,743	Jun 30, 2026	carried, not yet filed for the newest quarter
22	KENNEDY CAPITAL MANAGEMENT LLC 13F CIK 884589 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	336,377	1.32%	+229,586	Jun 30, 2026	carried, not yet filed for the newest quarter
23	Ophir Asset Management Pty Ltd 13F CIK 1844640 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	326,699	1.28%	+326,699	Jun 30, 2026	carried, not yet filed for the newest quarter
24	Granahan Investment Management, LLC 13F CIK 1026710 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	324,108	1.27%	-63,362	Jun 30, 2026	carried, not yet filed for the newest quarter
25	SILVERCREST ASSET MANAGEMENT GROUP LLC 13F CIK 1232395 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	313,943	1.23%	+44,262	Jun 30, 2026	carried, not yet filed for the newest quarter
26	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	291,168	1.14%	+5,318	Jun 30, 2026	carried, not yet filed for the newest quarter
26.1	STATE STREET SMALL/MID CAP EQUITY INDEX PORTFOLIO Fund S000050332 · Registered fund · Jun 30, 2026 STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed	4,700	0.02%	0	Jun 30, 2026	STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed
26.2	State Street Total Return V.I.S. Fund Fund S000001637 · Registered fund · Jun 30, 2026 STATE STREET VARIABLE INSURANCE SERIES FUNDS INC, not summed	370	0.00%	+5	Jun 30, 2026	STATE STREET VARIABLE INSURANCE SERIES FUNDS INC, not summed
27	Nuveen, LLC 13F CIK 1871926 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	281,914	1.11%	+234,496	Jun 30, 2026	carried, not yet filed for the newest quarter
27.1	Nuveen Quant Small Cap Equity Fund Fund S000005386 · Registered fund · Jul 31, 2026 TIAA-CREF Funds, not summed	244,330	0.96%	—	Jul 31, 2026	TIAA-CREF Funds, not summed
27.2	College Retirement Equities Fund - Total Global Stock Account Fund S000005080 · Registered fund · Jun 30, 2026 College Retirement Equities Fund, not summed	65,315	0.26%	—	Jun 30, 2026	College Retirement Equities Fund, not summed
27.3	Nuveen Equity Index Fund Fund S000005360 · Registered fund · Jul 31, 2026 TIAA-CREF Funds, not summed	26,893	0.11%	0	Jul 31, 2026	TIAA-CREF Funds, not summed
27.4	Nuveen Small Cap Blend Index Fund Fund S000005367 · Registered fund · Jul 31, 2026 TIAA-CREF Funds, not summed	19,432	0.08%	+3,303	Jul 31, 2026	TIAA-CREF Funds, not summed
27.5	Nuveen Life Small Cap Equity Fund Fund S000005093 · Registered fund · Jun 30, 2026 TIAA-CREF Life Funds, not summed	2,722	0.01%	—	Jun 30, 2026	TIAA-CREF Life Funds, not summed
28	BANK OF AMERICA CORP /DE/ 13F CIK 70858 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	276,317	1.08%	+92,718	Jun 30, 2026	carried, not yet filed for the newest quarter
29	MILLENNIUM MANAGEMENT LLC 13F CIK 1273087 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	253,677	0.99%	-127,295	Jun 30, 2026	carried, not yet filed for the newest quarter
30	JB CAPITAL PARTNERS LP 13F CIK 1138532 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	250,512	0.98%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
31	Squarepoint Ops LLC 13F CIK 1642575 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	238,766	0.94%	+128,197	Jun 30, 2026	carried, not yet filed for the newest quarter
32	Congruence Capital, LLC 13F CIK 2085569 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	235,580	0.92%	+1,105	Jun 30, 2026	carried, not yet filed for the newest quarter
33	Butz Todd M Insider CIK 1775975 · Mar 15, 2025 Director, issuer-wide	214,741	0.84%	+11,977	Mar 15, 2025	Director, issuer-wide
34	BRIDGEWAY CAPITAL MANAGEMENT, LLC 13F CIK 1107261 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	200,980	0.79%	-21,723	Jun 30, 2026	carried, not yet filed for the newest quarter
34.1	Omni Small-Cap Value Fund Fund S000033567 · Registered fund · Jun 30, 2026 Bridgeway Funds, Inc., not summed	82,810	0.32%	-15,000	Jun 30, 2026	Bridgeway Funds, Inc., not summed
35	TWO SIGMA INVESTMENTS, LP 13F CIK 1179392 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	198,912	0.78%	+164,204	Jun 30, 2026	carried, not yet filed for the newest quarter
36	CITADEL ADVISORS LLC 13F CIK 1423053 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	198,712	0.78%	+141,926	Jun 30, 2026	carried, not yet filed for the newest quarter
37	Boston Partners Small Cap Value Fund II Fund S000001094 · Registered fund · May 31, 2026 RBB Fund, Inc., not summed	198,187	0.78%	+32,461	May 31, 2026	RBB Fund, Inc., not summed
38	Brighthouse Small Cap Value Portfolio Fund S000011105 · Registered fund · Jun 30, 2026 Brighthouse Funds Trust I, not summed	182,990	0.72%	-111,663	Jun 30, 2026	Brighthouse Funds Trust I, not summed
39	AWM Investment Company, Inc. 13F CIK 1535264 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	180,000	0.71%	+180,000	Jun 30, 2026	carried, not yet filed for the newest quarter
40	OSTERWEIS CAPITAL MANAGEMENT INC 13F CIK 1007524 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	174,600	0.68%	+174,600	Jun 30, 2026	carried, not yet filed for the newest quarter
40.1	Osterweis Opportunity Fund Fund S000055531 · Registered fund · Jun 30, 2026 Professionally Managed Portfolios, not summed	112,250	0.44%	—	Jun 30, 2026	Professionally Managed Portfolios, not summed
41	TUDOR INVESTMENT CORP ET AL 13F CIK 923093 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	169,848	0.67%	+169,848	Jun 30, 2026	carried, not yet filed for the newest quarter
42	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	169,326	0.66%	+6,601	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
43	Christen Timothy L Insider CIK 1776003 · Apr 21, 2026 Director, issuer-wide	153,804	0.60%	+12,397	Apr 21, 2026	Director, issuer-wide
44	LORD, ABBETT & CO. LLC 13F CIK 728100 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	152,175	0.60%	+152,175	Jun 30, 2026	carried, not yet filed for the newest quarter
44.1	Lord Abbett Micro-Cap Growth Fund Fund S000007142 · Registered fund · Jul 31, 2026 LORD ABBETT SECURITIES TRUST, not summed	42,094	0.17%	—	Jul 31, 2026	LORD ABBETT SECURITIES TRUST, not summed
45	Wealthspire Advisors, LLC 13F CIK 1646247 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	141,607	0.56%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
46	Pillsbury Lake Capital LLC 13F CIK 2111915 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	136,746	0.54%	+136,746	Jun 30, 2026	carried, not yet filed for the newest quarter
47	Informed Momentum Co LLC 13F CIK 1510989 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	129,182	0.51%	+129,182	Jun 30, 2026	carried, not yet filed for the newest quarter
48	Reddy Jagadeesh A Insider CIK 1937748 · Jun 11, 2026 Director, President & CEO, issuer-wide	126,785	0.50%	-15,688	Jun 11, 2026	Director, President & CEO, issuer-wide
49	Russell Investments Group, Ltd. 13F CIK 1692234 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	125,513	0.49%	-12,702	Jun 30, 2026	carried, not yet filed for the newest quarter
49.1	Tax-Managed U.S. Mid & Small Cap Fund Fund S000001571 · Registered fund · Jul 31, 2026 RUSSELL INVESTMENT CO, not summed	94,311	0.37%	0	Jul 31, 2026	RUSSELL INVESTMENT CO, not summed
49.2	U.S. Small Cap Equity Fund Fund S000006864 · Registered fund · Jun 30, 2026 RUSSELL INVESTMENT FUNDS, not summed	1,203	0.00%	—	Jun 30, 2026	RUSSELL INVESTMENT FUNDS, not summed
50	Avantis U.S. Small Cap Value ETF Fund S000066459 · Registered fund · May 31, 2026 American Century ETF Trust, not summed	123,822	0.49%	-68,952	May 31, 2026	American Century ETF Trust, not summed

26 more nested rows are not shown here; Every filing lists them all.

Shares are restated onto today's split basis. Change compares each row with the same holder's previous filing in the same source; a dash means there is none to compare. Nested 13D/G, insider and fund rows are not summed, since a 13F report already holds them.

Showing 1–50 of 254 holders

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Key facts CIK 1766368 CUSIP 578605107 13F (30d) 9 filings 9 filers Visit website Investor relations