MAYVILLE ENGINEERING CO INC (MEC) Institutional Shareholders
MAYVILLE ENGINEERING CO INC (MEC) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $754.39M in MEC holdings during the latest filing period.
Portolan Capital Management, Llc is currently the largest disclosed institutional shareholder of MEC tracked by InsiderSet, reporting ownership valued at approximately $48.67M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $31.30M, representing an estimated loss of -35.69% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 47% of the total disclosed MEC value among the investors covered in this analysis. Major shareholders include Portolan Capital Management, Llc, Fmr Llc, Blackrock, Inc., and several other long-term asset managers with concentrated positions in MAYVILLE ENGINEERING CO INC (MEC).
This page ranks the largest institutional MEC shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
153
Total Reported Value
$754.39M
Largest Holder
Portolan Capital Management, Llc
Largest Position
$48.67M
Insider Transactions (90d)
6
Latest Filing Quarter
Q2 2026
New Institutional Positions
132
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Portolan Capital Management, Llc | 1.82% | 1,299,256 | $48,670,130 | $31,299,077 | -$17,371,053 | -35.69% | |
| Fmr Llc | 0.00% | 1,280,170 | $47,955,173 | $30,839,295 | -$17,115,878 | -35.69% | |
| Blackrock, Inc. | 0.00% | 1,183,443 | $44,331,785 | $28,509,142 | -$15,822,643 | -35.69% | |
| Allspring Global Investments Holdings, Llc | 0.06% | 1,072,916 | $37,777,372 | $25,846,546 | -$11,930,826 | -31.58% | |
| Driehaus Capital Management Llc | 0.18% | 846,354 | $31,704,421 | $20,388,668 | -$11,315,753 | -35.69% | |
| Summit Partners Public Asset Management, Llc | 0.78% | 800,000 | $29,968,000 | $19,272,000 | -$10,696,000 | -35.69% | |
| Dimensional Fund Advisors Lp | 0.01% | 782,276 | $29,304,240 | $18,845,029 | -$10,459,211 | -35.69% | |
| Royce & Associates Lp | 0.23% | 752,083 | $28,173,029 | $18,117,679 | -$10,055,350 | -35.69% | |
| Vanguard Capital Management Llc | 0.00% | 743,621 | $27,856,043 | $17,913,830 | -$9,942,213 | -35.69% | |
| Boston Partners | 0.02% | 696,429 | $25,813,603 | $16,776,975 | -$9,036,628 | -35.01% | |
| Blair William & Co/Il | 0.05% | 546,714 | $20,479,906 | $13,170,340 | -$7,309,566 | -35.69% | |
| Wellington Management Group Llp | 0.00% | 477,583 | $17,890,259 | $11,504,974 | -$6,385,285 | -35.69% | |
| Evr Research Lp | 8.17% | 441,908 | $16,553,874 | $10,645,564 | -$5,908,310 | -35.69% | |
| Geode Capital Management, Llc | 0.00% | 374,578 | $14,035,404 | $9,023,584 | -$5,011,820 | -35.71% | |
| First Eagle U.S. Value | Jean-Marie Eveillard | 0.02% | 369,575 | $13,844,280 | $8,903,062 | -$4,941,218 | -35.69% |
| Jane Street Group, Llc | 0.01% | 356,151 | $13,341,417 | $8,579,678 | -$4,761,739 | -35.69% | |
| Jpmorgan Chase & Co | 0.00% | 347,224 | $13,034,789 | $8,364,626 | -$4,670,163 | -35.83% | |
| Kennedy Capital Management Llc | 0.22% | 336,377 | $12,600,682 | $8,103,322 | -$4,497,360 | -35.69% | |
| Ophir Asset Management Pty Ltd | 1.01% | 326,699 | $12,238,145 | $7,870,179 | -$4,367,966 | -35.69% | |
| Granahan Investment Management, Llc | 0.43% | 324,108 | $12,141,086 | $7,807,762 | -$4,333,324 | -35.69% | |
| Silvercrest Asset Management Group Llc | 0.08% | 313,943 | $11,760,305 | $7,562,887 | -$4,197,418 | -35.69% | |
| State Street Corp | 0.00% | 291,168 | $10,907,153 | $7,014,237 | -$3,892,916 | -35.69% | |
| Nuveen, Llc | 0.00% | 281,914 | $10,560,498 | $6,791,308 | -$3,769,190 | -35.69% | |
| Bank Of America Corp | 0.00% | 276,317 | $10,350,836 | $6,656,477 | -$3,694,359 | -35.69% | |
| Millennium Management Llc | 0.01% | 253,677 | $9,502,740 | $6,111,079 | -$3,391,661 | -35.69% | |
| Jb Capital Partners Lp | 1.45% | 250,512 | $9,384,180 | $6,034,834 | -$3,349,346 | -35.69% | |
| Squarepoint Ops Llc | 0.02% | 238,766 | $8,944,174 | $5,751,873 | -$3,192,301 | -35.69% | |
| Congruence Capital, Llc | 2.31% | 235,580 | $8,824,827 | $5,675,122 | -$3,149,705 | -35.69% | |
| Bridgeway Capital Management, Llc | 0.13% | 200,980 | $7,528,711 | $4,841,608 | -$2,687,103 | -35.69% | |
| Two Sigma Investments, Lp | 0.01% | 198,912 | $7,451,244 | $4,791,790 | -$2,659,454 | -35.69% | |
| Citadel Advisors Llc | 0.00% | 198,712 | $7,443,751 | $4,786,972 | -$2,656,779 | -35.69% | |
| Awm Investment Company, Inc. | 0.59% | 180,000 | $6,742,800 | $4,336,200 | -$2,406,600 | -35.69% | |
| Osterweis Capital Management Inc | 0.31% | 174,600 | $6,540,516 | $4,206,114 | -$2,334,402 | -35.69% | |
| Tudor Investment Corp Et Al | 0.03% | 169,848 | $6,362,506 | $4,091,638 | -$2,270,868 | -35.69% | |
| Wealthspire Advisors, Llc | 0.03% | 141,607 | $5,304,599 | $3,411,313 | -$1,893,286 | -35.69% | |
| Pillsbury Lake Capital Llc | 1.41% | 136,746 | $5,122,505 | $3,294,211 | -$1,828,294 | -35.69% | |
| Informed Momentum Co Llc | 0.43% | 129,182 | $4,839,158 | $3,111,994 | -$1,727,164 | -35.69% | |
| Russell Investments Group, Ltd. | 0.00% | 125,513 | $4,701,717 | $3,023,608 | -$1,678,109 | -35.69% | |
| Sei Investments Co | 0.00% | 118,607 | $4,443,020 | $2,857,243 | -$1,585,777 | -35.69% | |
| Empowered Funds, Llc | 0.02% | 116,570 | $4,366,712 | $2,808,171 | -$1,558,541 | -35.69% | |
| Northern Trust Corp | 0.00% | 114,995 | $4,307,712 | $2,770,230 | -$1,537,482 | -35.69% | |
| Bnp Paribas Financial Markets | 0.00% | 112,455 | $4,212,564 | $2,709,041 | -$1,503,523 | -35.69% | |
| Needham Investment Management Llc | 0.12% | 110,000 | $4,120,600 | $2,649,900 | -$1,470,700 | -35.69% | |
| Trexquant Investment Lp | 0.02% | 100,517 | $3,765,367 | $2,421,455 | -$1,343,912 | -35.69% | |
| Morgan Stanley | 0.00% | 100,159 | $3,751,970 | $2,412,830 | -$1,339,140 | -35.69% | |
| Vanguard Fiduciary Trust Co | 0.00% | 98,709 | $3,697,639 | $2,377,900 | -$1,319,739 | -35.69% | |
| Vanguard Portfolio Management Llc | 0.00% | 98,263 | $3,680,932 | $2,367,156 | -$1,313,776 | -35.69% | |
| Walleye Capital Llc | 0.02% | 93,444 | $3,500,412 | $2,251,066 | -$1,249,346 | -35.69% | |
| Qube Research & Technologies Ltd | 0.00% | 87,129 | $3,263,852 | $2,098,938 | -$1,164,914 | -35.69% | |
| Susquehanna International Group, Llp | 0.00% | 85,462 | $3,201,407 | $2,058,780 | -$1,142,627 | -35.69% |
Frequently asked questions about MEC
Who owns the most MEC stock?
The largest holders of MEC are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for MAYVILLE ENGINEERING CO INC (MEC).
Is MEC widely held by superinvestors?
Many widely followed stocks like MEC appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly MEC is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.