Mayville Engineering Company, Inc. (MEC) Ownership
MEC ownership summary
as of October 18, 2026- Institutions
- 84.3% of shares outstanding
- Insiders
- 23.36% of shares outstanding
- Shares outstanding
- 25.5M
- Float
- 18.4M shares available to trade
- Short interest
- 11.76% 2.4M shares short
- Days to cover
- 4.50 short interest up 31.1% vs prior month
- Institutions 84.32%
- Insiders 23.36%
MEC top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Portolan Capital Management, LLC | 5.10% | 1.3M | $18.1M | +478,120 (+58.2%) | June 30, 2026 |
| 2 | FMR Inc | 5.02% | 1.3M | $17.8M | +1.3M (+29,943.9%) | June 30, 2026 |
| 3 | BlackRock Inc | 4.64% | 1.2M | $16.4M | +301,589 (+34.2%) | June 30, 2026 |
| 4 | Allspring Global Investments Holdings, LLC | 4.21% | 1.1M | $14.9M | −927,434 (−46.4%) | June 30, 2026 |
| 5 | Driehaus Capital Management LLC | 3.32% | 846K | $11.8M | +846,354 (0.0%) | June 30, 2026 |
| 6 | Summit Partners Public Asset Management, LLC | 3.14% | 800K | $11.1M | +800,000 (0.0%) | June 30, 2026 |
| 7 | Dimensional Fund Advisors, Inc. | 3.07% | 782K | $10.9M | −143,940 (−15.5%) | June 30, 2026 |
| 8 | Royce & Associates, LP | 2.95% | 752K | $10.5M | +1,082 (+0.1%) | June 30, 2026 |
| 9 | Vanguard Capital Management, LLC | 2.92% | 744K | $10.3M | +148,683 (+25.0%) | June 30, 2026 |
| 10 | Arnhold & S. Bleichroeder Advisers, LLC | 2.90% | 739K | $10.3M | +335,075 (+82.9%) | June 30, 2026 |
| 11 | Boston Partners Global Investors, Inc | 2.73% | 696K | $9.7M | +463,792 (+199.4%) | June 30, 2026 |
| 12 | Jupiter Topco LLC | 2.26% | 575K | $8.0M | +575,278 (0.0%) | June 30, 2026 |
| 13 | Blair William & Co | 2.14% | 547K | $7.6M | −18,586 (−3.3%) | June 30, 2026 |
| 14 | Wellington Management Company LLP | 1.87% | 478K | $6.6M | +477,583 (0.0%) | June 30, 2026 |
| 15 | EVR Research LP | 1.73% | 442K | $6.1M | −178,092 (−28.7%) | June 30, 2026 |
| 16 | Geode Capital Management, LLC | 1.47% | 375K | $5.2M | +38,743 (+11.5%) | June 30, 2026 |
| 17 | Jane Street Group LLC | 1.40% | 356K | $5.0M | +356,151 (0.0%) | June 30, 2026 |
| 18 | JPMorgan Chase & Co | 1.36% | 347K | $4.8M | +341,743 (+6,235.0%) | June 30, 2026 |
| 19 | Kennedy Capital Management Inc | 1.32% | 336K | $4.7M | +229,586 (+215.0%) | June 30, 2026 |
| 20 | Ophir Asset Management Pty Ltd | 1.28% | 327K | $4.5M | +326,699 (0.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 16 holders added 7.0M shares and 4 cut 1.3M.
MEC top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Fidelity Growth Strategies | 5.03% | 1.3M | $17.8M | −33,800 (−2.6%) | August 31, 2026 |
| 2 | Allspring Special Small Cap Value A | 2.63% | 670K | $9.3M | +95,379 (+16.6%) | August 31, 2026 |
| 3 | Vanguard MStar Total Stk Mkt Idx Invest | 2.18% | 556K | $7.7M | — | August 31, 2026 |
| 4 | iShares Russell 2000 ETF | 2.14% | 545K | $7.6M | −6,272 (−1.1%) | September 30, 2026 |
| 5 | Janus Henderson Venture D | 1.87% | 476K | $6.6M | +1,692 (+0.4%) | August 31, 2026 |
| 6 | Royce Small-Cap Opportunity Invmt | 1.39% | 354K | $4.9M | −32,412 (−8.4%) | June 30, 2026 |
| 7 | Fidelity Growth Strategies K6 | 1.33% | 340K | $4.7M | −8,800 (−2.5%) | August 31, 2026 |
| 8 | Heptagon Driehaus US Micro Cap Eq C$ Acc | 1.31% | 334K | $4.6M | — | August 31, 2026 |
| 9 | FTGF RY US SmCp Opp A USD Dis(A) | 1.29% | 329K | $4.6M | −10,067 (−3.0%) | August 31, 2026 |
| 10 | Nuveen Quant Small Cap Equity R6 | 0.96% | 244K | $3.4M | — | August 31, 2026 |
| 11 | First Eagle Small Cap Opportunity I | 0.93% | 236K | $3.3M | −8,866 (−3.6%) | August 31, 2026 |
| 12 | CREF Total Global Stock Account R3 | 0.82% | 209K | $2.9M | +121,050 (+137.2%) | July 31, 2026 |
| 13 | iShares Russell 2000 Value ETF | 0.81% | 206K | $2.9M | +312 (+0.2%) | September 30, 2026 |
| 14 | Brighthouse Small Cap Value A | 0.68% | 173K | $2.4M | −121,738 (−41.3%) | June 30, 2026 |
| 15 | Fidelity Small Cap Index | 0.63% | 160K | $2.2M | +1,516 (+1.0%) | July 31, 2026 |
| 16 | Driehaus Micro Cap Growth USD | 0.52% | 133K | $1.9M | — | July 31, 2026 |
| 17 | EA Bridgeway Omni Small-Cap Value ETF | 0.50% | 127K | $1.8M | — | September 30, 2026 |
| 18 | Osterweis Opportunity Fund | 0.44% | 112K | $1.6M | +112,250 (0.0%) | June 30, 2026 |
| 19 | Needham Small Cap Growth Retail | 0.43% | 110K | $1.5M | +90,000 (+450.0%) | June 30, 2026 |
| 20 | Dimensional US Targeted Value ETF | 0.39% | 99K | $1.4M | — | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
MEC insider transactions
latest 7| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-05 | Sean P Leuba | Sell | $18.81 | 6,698 | $125,989 |
| 2026-03-05 | Sean P Leuba | Sell | $20.07 | 2,500 | $50,175 |
| 2025-12-11 | Steven L Fisher | Sell | $19.11 | 10,000 | $191,100 |
| 2025-11-25 | Ryan F Raber | Sell | $16.68 | 15,000 | $250,200 |
| 2025-08-11 | Sean P Leuba | Buy | $13.56 | 500 | $6,780 |
| 2025-08-08 | Rachele Marie Lehr | Buy | $14.08 | 1,400 | $19,712 |
| 2025-08-07 | Jagadeesh A Reddy | Buy | $14.06 | 7,500 | $105,450 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
MEC shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns MEC
Institutional investors own 84.3% of Mayville Engineering's shares and insiders 23.36%. The largest holder is Portolan Capital Management, LLC with 5.10% of the shares (1.3M), as of June 30, 2026. Among the top 20 institutions, 16 added shares and 4 reduced their stake in the latest filings. Short interest is 11.76% of the float, or 4.50 days of average trading volume. The share count rose 45.9% since 2017.
Related: MEC analyst forecast, MEC key metrics. See the MEC stock overview for the latest quote and news.
MEC ownership FAQ
Who owns the most Mayville Engineering stock?
The largest shareholders of Mayville Engineering are Portolan Capital Management, LLC (5.10%), FMR Inc (5.02%), BlackRock Inc (4.64%), Allspring Global Investments Holdings, LLC (4.21%), Driehaus Capital Management LLC (3.32%).
What percentage of Mayville Engineering is owned by institutions?
Institutions hold 84.3% of Mayville Engineering's shares outstanding; insiders hold 23.36%.
Which funds own Mayville Engineering?
The largest fund holders of Mayville Engineering are Fidelity Growth Strategies (5.03%), Allspring Special Small Cap Value A (2.63%), Vanguard MStar Total Stk Mkt Idx Invest (2.18%), iShares Russell 2000 ETF (2.14%), Janus Henderson Venture D (1.87%).
What is Mayville Engineering's short interest?
2.4M shares of Mayville Engineering were sold short, 11.76% of the float; at the average daily volume it would take 4.50 days to cover.
Are insiders buying or selling Mayville Engineering?
Of the latest 7 reported insider transactions in Mayville Engineering (since August 7, 2025), 3 were purchases and 4 were sales.
How many shares of Mayville Engineering are outstanding?
Mayville Engineering has 25.5M shares outstanding, of which 18.4M are in the public float.