MEC · Mayville Engineering Company, Inc.

$19.20 -0.16 (-0.83%)

Russell 2000 member Rebalance outlook locked

Market Cap

$492.67M

25.50M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Quarter:

Holders: 156

Total Value: $818,410,963

Total Shares: 21,847,599

Showing 1–100 of 164 holdings by value · page 1 of 2

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 156 13F filers · Δ vs Mar 31, 2026

Top Holder

5.9%

−7.9 pts

Top 5

26.0%

−11.4 pts

Top 10

43.3%

−11.9 pts

HHI

266

Broadly held−188

Quarterly Activity

vs Mar 31, 2026

New

Increased

Decreased

Sold Out

Unchanged

Holder count: +32

Institutional value: +216.6%

Shares held: +51.7%

Top Buyers

vs Mar 31, 2026

Institution	Added	Now Holds
Mega FMR LLC	+1,275,909	1,280,170
Mid Portolan Capital Management, LLC	+478,120	1,299,256
Mega Boston Partners	+463,792	696,429
Mega JPMORGAN CHASE & CO	+341,743	347,224
Mega BlackRock, Inc.	+301,589	1,183,443

Top Sellers

vs Mar 31, 2026

Institution	Sold	Now Holds
Large Allspring Global Investments Holdings, LLC	−927,434	1,072,916
Small EVR Research LP	−178,092	441,908
Mega AMERICAN CENTURY COMPANIES INC	−173,462	48,211
Mega DIMENSIONAL FUND ADVISORS LP	−143,940	782,276
Mega MILLENNIUM MANAGEMENT LLC	−127,295	253,677

Top New Positions

vs Mar 31, 2026

Institution	Acquired	Value (USD)
Large Driehaus Capital Management LLC	846,354	$31,704,420
Mid SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC	800,000	$29,968,000
Mega Jupiter Topco LLC	575,278	$21,549,913
Mega WELLINGTON MANAGEMENT GROUP LLP	477,583	$17,890,257
Mega JANE STREET GROUP, LLC	403,351	$15,109,527

Top Sold-Out Positions

vs Mar 31, 2026

Institution	Previously Held	Last Value (USD)
Mega AMERIPRISE FINANCIAL INC	351,790	$6,314,630
Small Roubaix Capital, LLC	210,657	$3,781,293
Mega ARROWSTREET CAPITAL, LIMITED PARTNERSHIP	185,261	$3,325,434
Small Integrated Quantitative Investments LLC	50,659	$909,329
Large HighTower Advisors, LLC	44,587	$800,336

Filter: New 55 Increased 44 Reduced 39 Sold out 23 Unchanged 18

Showing 100 of 164

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

Portolan Capital Management, LLC

$48,670,129

5.95%

1,299,256

FMR LLC

$47,955,167

5.86%

1,280,170

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Fidelity Management & Research Co LLC	1,232,519	$46,170,161	96.3%	Defined
STRATEGIC ADVISERS LLC	264	$9,889	0.0%	Defined
FIAM LLC	47,387	$1,775,117	3.7%	Defined

BlackRock, Inc.

$44,331,772

5.42%

1,183,443

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BLACKROCK FINANCIAL MANAGEMENT INC/DE	5,770	$216,144	0.5%	Sole
BlackRock Investment Management, LLC	45,764	$1,714,319	3.9%	Sole
BLACKROCK ADVISORS LLC	34,141	$1,278,921	2.9%	Sole
BlackRock Fund Advisors	602,859	$22,583,098	50.9%	Sole
BlackRock Institutional Trust Company, N.A.	471,576	$17,665,236	39.8%	Sole
Aperio Group, LLC	23,333	$874,054	2.0%	Sole

Allspring Global Investments Holdings, LLC

$40,191,432

4.91%

1,072,916

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Allspring Funds Management, LLC reporting on behalf of Morgan Stanley Smith Barney, LLC	610	$22,850	0.1%	Defined
Allspring Global Investments, LLC reporting on behalf of UBS ASSET MANAGEMENT AMERICAS INC	1,072,306	$40,168,582	99.9%	Defined

Driehaus Capital Management LLC

$31,704,420

3.87%

846,354

SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC

$29,968,000

3.66%

800,000

DIMENSIONAL FUND ADVISORS LP

$29,304,057

3.58%

782,276

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Dimensional Fund Advisors Ltd.	2,263	$84,771	0.3%	Defined
DFA Australia Ltd.	7,118	$266,640	0.9%	Defined
Dimensional Ireland Ltd	24,947	$934,514	3.2%	Defined
Held directly	747,948	$28,018,132	95.6%	Sole

ROYCE & ASSOCIATES LP

$28,173,029

3.44%

752,083

VANGUARD CAPITAL MANAGEMENT LLC

$27,856,042

3.40%

743,621

Boston Partners

$26,088,230

3.19%

696,429

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Boston Partners Trust Co	109,833	$4,114,344	15.8%	Defined
Held directly	586,596	$21,973,886	84.2%	Defined

Jupiter Topco LLC

$21,549,913

2.63%

575,278

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
JANUS HENDERSON INVESTORS US LLC	561,975	$21,051,583	97.7%	Defined
Held directly	13,303	$498,330	2.3%	Defined

BLAIR WILLIAM & CO/IL

$20,479,906

2.50%

546,714

WELLINGTON MANAGEMENT GROUP LLP

$17,890,257

2.19%

477,583

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Wellington Management Company LLP	376,703	$14,111,294	78.9%	Defined
Wellington Managment Canada LLC	29,485	$1,104,508	6.2%	Defined
Wellington Management Singapore Pte. Ltd.	20,045	$750,885	4.2%	Defined
Wellington Management International Ltd	7,594	$284,471	1.6%	Defined
Wellington Trust Company, NA joint	43,756	$1,639,099	9.2%	Defined

EVR Research LP

$16,553,873

2.02%

441,908

GEODE CAPITAL MANAGEMENT, LLC

$14,031,691

1.71%

374,578

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GEODE CAPITAL MANAGEMENT TRUST COMPANY, LLC	54,480	$2,040,820	14.5%	Defined
Held directly	320,098	$11,990,871	85.5%	Defined

First Eagle Investment Management, LLC

$13,844,279

1.69%

369,575

JANE STREET GROUP, LLC

$13,341,415

1.63%

356,151

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	310,234	$11,621,365	87.1%	Defined
Jane Street Global Trading, LLC	45,917	$1,720,050	12.9%	Defined

JPMORGAN CHASE & CO

$13,007,010

1.59%

347,224

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
JPMorgan Chase Bank, N.A.	6,071	$227,419	1.7%	Defined
J.P. Morgan Investment Management Inc.	946	$35,437	0.3%	Defined
J.P. Morgan Securities LLC	340,207	$12,744,154	98.0%	Defined

KENNEDY CAPITAL MANAGEMENT LLC

$12,600,682

1.54%

336,377

Ophir Asset Management Pty Ltd

$12,238,144

1.50%

326,699

Granahan Investment Management, LLC

$12,141,085

1.48%

324,108

SILVERCREST ASSET MANAGEMENT GROUP LLC

$11,760,304

1.44%

313,943

STATE STREET CORP

$10,907,153

1.33%

291,168

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
STATE STREET GLOBAL ADVISORS EUROPE LIMITED joint	291,168	$10,907,153	100.0%	Defined

Nuveen, LLC

$10,560,497

1.29%

281,914

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Nuveen Asset Management, LLC joint	11,800	$442,027	4.2%	Defined
TIAA CREF INVESTMENT MANAGEMENT LLC joint	88,250	$3,305,845	31.3%	Defined
TEACHERS ADVISORS, LLC joint	181,864	$6,812,625	64.5%	Defined

BANK OF AMERICA CORP /DE/

$10,350,832

1.26%

276,317

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BANK OF AMERICA NA	131,203	$4,914,864	47.5%	Defined
BOFA SECURITIES, INC.	37,504	$1,404,899	13.6%	Defined
MANAGED ACCOUNT ADVISORS LLC joint	107,610	$4,031,069	38.9%	Defined

MILLENNIUM MANAGEMENT LLC

$9,502,740

1.16%

253,677

JB CAPITAL PARTNERS LP

$9,384,179

1.15%

250,512

Squarepoint Ops LLC

$8,944,174

1.09%

238,766

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Squarepoint Capital LLP	238,766	$8,944,174	100.0%	Defined

Congruence Capital, LLC

$8,824,825

1.08%

235,580

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SummitTX Capital, L.P.	134,913	$5,053,840	57.3%	Other
Held directly	100,667	$3,770,985	42.7%	Sole

BRIDGEWAY CAPITAL MANAGEMENT, LLC

$7,528,710

0.92%

200,980

TWO SIGMA INVESTMENTS, LP

$7,451,243

0.91%

198,912

CITADEL ADVISORS LLC

$7,443,751

0.91%

198,712

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	112,488	$4,213,800	56.6%	Defined
Held directly	86,224	$3,229,951	43.4%	Defined

AWM Investment Company, Inc.

$6,742,800

0.82%

180,000

OSTERWEIS CAPITAL MANAGEMENT INC

$6,540,516

0.80%

174,600

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
OSTERWEIS CAPITAL MANAGEMENT LLC/CA	174,600	$6,540,516	100.0%	Sole

TUDOR INVESTMENT CORP ET AL

$6,362,506

0.78%

169,848

LORD, ABBETT & CO. LLC

$5,700,475

0.70%

152,175

PEAK6 LLC

$5,619,000

0.69%

150,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
PEAK6 Investments LLC joint	150,000	$5,619,000	100.0%	Defined

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$5,611,508

0.69%

149,800

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	149,800	$5,611,508	100.0%	Other

Wealthspire Advisors, LLC

$5,304,598

0.65%

141,607

Pillsbury Lake Capital LLC

$5,122,505

0.63%

136,746

Informed Momentum Co LLC

$4,839,157

0.59%

129,182

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$4,727,452

0.58%

126,200

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	126,200	$4,727,452	100.0%	Other

Russell Investments Group, Ltd.

$4,701,712

0.57%

125,513

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Russell Investment Management, LLC	111,625	$4,181,471	88.9%	Defined
Russell Investments Canada Limited	562	$21,052	0.4%	Defined
Russell Investments Capital, LLC	7,345	$275,143	5.9%	Defined
Russell Investments France SAS	2,101	$78,703	1.7%	Defined
Russell Investments Limited	741	$27,757	0.6%	Defined
Russell Investments Trust Company	3,139	$117,586	2.5%	Defined

SEI INVESTMENTS CO

$4,443,017

0.54%

118,607

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SEI INVESTMENTS MANAGEMENT CORP	44	$1,648	0.0%	Sole
SEI TRUST CO	118,563	$4,441,369	100.0%	Sole

Empowered Funds, LLC

$4,366,712

0.53%

116,570

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Bridgeway Capital Management, LLC	116,570	$4,366,712	100.0%	Other

NORTHERN TRUST CORP

$4,307,712

0.53%

114,995

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
NORTHERN TRUST CO joint	112,690	$4,221,367	98.0%	Defined
DWS INVESTMENT MANAGEMENT AMERICAS, INC joint	2,305	$86,345	2.0%	Other

BNP PARIBAS ARBITRAGE, SA

$4,212,564

0.51%

112,455

NEEDHAM INVESTMENT MANAGEMENT LLC

$4,120,600

0.50%

110,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Needham Small Cap Growth Fund	110,000	$4,120,600	100.0%	Defined

HUNTER ASSOCIATES INVESTMENT MANAGEMENT LLC

$4,027,998

0.49%

107,528

Trexquant Investment LP

$3,765,366

0.46%

100,517

MORGAN STANLEY

$3,751,953

0.46%

100,159

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY & CO INTERNATIONAL PLC	13	$486	0.0%	Defined
MORGAN STANLEY & CO. LLC	6,137	$229,892	6.1%	Defined
MORGAN STANLEY CAPITAL SERVICES, LLC	77,897	$2,918,021	77.8%	Defined
MORGAN STANLEY SMITH BARNEY LLC	6,967	$260,983	7.0%	Defined
PARAMETRIC PORTFOLIO ASSOCIATES LLC	9,145	$342,571	9.1%	Defined

VANGUARD FIDUCIARY TRUST CO

$3,697,639

0.45%

98,709

VANGUARD PORTFOLIO MANAGEMENT LLC

$3,680,931

0.45%

98,263

Walleye Capital LLC

$3,500,412

0.43%

93,444

Qube Research & Technologies Ltd

$3,263,852

0.40%

87,129

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$3,201,406

0.39%

85,462

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	85,462	$3,201,406	100.0%	Other

UBS Group AG

$3,096,518

0.38%

82,662

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS Financial Services Inc	98	$3,671	0.1%	Defined
UBS AG	82,414	$3,087,228	99.7%	Defined
UBS Securities LLC	150	$5,619	0.2%	Defined

ANCHOR CAPITAL ADVISORS LLC

$3,029,914

0.37%

80,884

Invesco Ltd.

$2,821,898

0.34%

75,331

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Invesco Advisers, Inc. joint	1,780	$66,678	2.4%	Defined
Invesco Trust Co joint	5,800	$217,268	7.7%	Defined
Invesco Capital Management LLC	67,751	$2,537,952	89.9%	Defined

FORMULA GROWTH LTD

$2,809,500

0.34%

75,000

TOCQUEVILLE ASSET MANAGEMENT L.P.

$2,663,406

0.33%

71,100

Panoramic Capital, LLC

$2,622,200

0.32%

70,000

XTX Topco Ltd

$2,457,525

0.30%

65,604

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
XTX EXECUTION SERVICES LLC joint	65,604	$2,457,525	100.0%	Defined

Caption Management, LLC

$2,341,250

0.29%

62,500

POLEN CAPITAL MANAGEMENT LLC

$2,316,039

0.28%

61,827

Essential Investment Partners LLC

$2,205,869

0.27%

58,886

CITIGROUP INC

$1,971,144

0.24%

52,620

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citigroup Financial Products Inc. joint	52,620	$1,971,144	100.0%	Defined

GOLDMAN SACHS GROUP INC

$1,947,544

0.24%

51,990

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GOLDMAN SACHS & CO. LLC	32,432	$1,214,902	62.4%	Defined
GOLDMAN SACHS ASSET MANAGEMENT, L.P.	19,558	$732,642	37.6%	Defined

AMERICAN CENTURY COMPANIES INC

$1,805,984

0.22%

48,211

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
AMERICAN CENTURY INVESTMENT MANAGEMENT INC	48,211	$1,805,984	100.0%	Defined

Balyasny Asset Management L.P.

$1,762,567

0.22%

47,052

CHARLES SCHWAB INVESTMENT MANAGEMENT INC

$1,717,953

0.21%

45,861

SummerHaven Investment Management, LLC

$1,697,874

0.21%

45,325

Bank of New York Mellon Corp

$1,680,941

0.21%

44,873

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Mellon Investments Corporation	19,984	$748,600	44.5%	Defined
The Bank of New York Mellon	24,820	$929,757	55.3%	Defined
BNY Mellon, NA	69	$2,584	0.2%	Defined

CITADEL ADVISORS LLC

$1,603,288

0.20%

42,800

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	42,800	$1,603,288	100.0%	Defined

GatePass Capital, LLC

$1,498,400

0.18%

40,000

OSAIC HOLDINGS, INC.

$1,483,940

0.18%

39,614

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
OSAIC WEALTH, INC.	39,614	$1,483,940	100.0%	Defined

SHEETS SMITH WEALTH MANAGEMENT

$1,419,621

0.17%

37,897

Caption Management, LLC

$1,404,750

0.17%

37,500

Diametric Capital, LP

$1,338,333

0.16%

35,727

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Thakore Nainoor	35,727	$1,338,333	100.0%	Defined

Aquatic Capital Management LLC

$1,188,643

0.15%

31,731

Janney Montgomery Scott LLC

$1,172,647

0.14%

31,304

CenterBook Partners LP

$1,160,960

0.14%

30,992

BOOTHBAY FUND MANAGEMENT, LLC

$1,145,676

0.14%

30,584

North Star Investment Management Corp.

$1,123,800

0.14%

30,000

J. Goldman & Co LP

$1,123,800

0.14%

30,000

KORNITZER CAPITAL MANAGEMENT INC /KS

$1,108,329

0.14%

29,587

HARBOR CAPITAL ADVISORS, INC.

$1,072,292

0.13%

28,625

RENAISSANCE TECHNOLOGIES LLC

$1,048,880

0.13%

28,000

Divisadero Street Capital Management, LP

$1,029,475

0.13%

27,482

JANE STREET GROUP, LLC

$1,015,166

0.12%

27,100

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	27,100	$1,015,166	100.0%	Defined

Quadrature Capital Ltd

$991,828

0.12%

26,477

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Quadrature US Inc.	26,477	$991,828	100.0%	Other

Johnson Financial Group, Inc.

$973,960

0.12%

26,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Johnson Wealth Inc.	26,000	$973,960	100.0%	Defined

CITADEL ADVISORS LLC

$932,754

0.11%

24,900

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	24,900	$932,754	100.0%	Defined

PRELUDE CAPITAL MANAGEMENT, LLC

$897,878

0.11%

23,969

LPL Financial LLC

$830,563

0.10%

22,172

O'SHAUGHNESSY ASSET MANAGEMENT, LLC

$816,066

0.10%

21,785

HRT FINANCIAL LP

$807,937

0.10%

21,568

WELLS FARGO & COMPANY/MN

$760,437

0.09%

20,300

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
WELLS FARGO BANK N A	12,266	$459,484	60.4%	Defined
WELLS FARGO ADVISORS FINANCIAL NETWORK, LLC	3,970	$148,716	19.6%	Defined
WELLS FARGO CLEARING SERVICES, LLC	4,064	$152,237	20.0%	Defined

JANE STREET GROUP, LLC

$752,946

0.09%

20,100

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	20,100	$752,946	100.0%	Defined

RHUMBLINE ADVISERS

$749,237

0.09%

20,001

Key facts CIK 1766368 CUSIP 578605107 13F (30d) 133 filings 132 filers Visit website Investor relations