MAGNITE INC (MGNI) Top Institutional Shareholders
MAGNITE INC (MGNI) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended March 31, 2026. The institutional investors covered on this page collectively reported approximately $1.54B in MGNI holdings during the latest filing period.
Blackrock, Inc. is currently the largest disclosed institutional shareholder of MGNI tracked by InsiderSet, reporting ownership valued at approximately $138.49M in its March 31, 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 $212.63M, representing an estimated gain of +53.54% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 47% of the total disclosed MGNI value among the investors covered in this analysis. Major shareholders include Blackrock, Inc., Wellington Management Group Llp, Vanguard Portfolio Management Llc, and several other long-term asset managers with concentrated positions in MAGNITE INC (MGNI).
This page ranks the largest institutional MGNI 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
291
Total Reported Value
$1.54B
Largest Holder
Blackrock, Inc.
Largest Position
$138.49M
Insider Transactions (90d)
0
Latest Filing Quarter
Q1 2026
New Institutional Positions
103
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Blackrock, Inc. | 0.00% | 11,657,496 | $138,491,059 | $212,632,727 | +$74,141,668 | +53.54% | |
| Wellington Management Group Llp | 0.02% | 9,191,077 | $109,189,995 | $167,645,244 | +$58,455,249 | +53.54% | |
| Vanguard Portfolio Management Llc | 0.00% | 7,726,205 | $91,787,315 | $140,925,979 | +$49,138,664 | +53.54% | |
| Vanguard Capital Management Llc | 0.00% | 6,190,403 | $73,541,988 | $112,912,951 | +$39,370,963 | +53.54% | |
| Capital Research Global Investors | 0.01% | 5,020,289 | $59,641,033 | $91,570,071 | +$31,929,038 | +53.54% | |
| Boston Partners | 0.06% | 4,719,863 | $56,078,770 | $86,090,301 | +$30,011,531 | +53.52% | |
| American Century Companies Inc | 0.03% | 4,626,816 | $54,966,590 | $84,393,124 | +$29,426,534 | +53.54% | |
| Fmr Llc | 0.00% | 4,507,419 | $53,548,133 | $82,215,323 | +$28,667,190 | +53.54% | |
| Dimensional Fund Advisors Lp | 0.01% | 3,983,674 | $47,321,837 | $72,662,214 | +$25,340,377 | +53.55% | |
| Nuveen, Llc | 0.01% | 3,590,025 | $42,649,497 | $65,482,056 | +$22,832,559 | +53.54% | |
| Geode Capital Management, Llc | 0.00% | 3,553,790 | $42,226,958 | $64,821,130 | +$22,594,172 | +53.51% | |
| Nine Ten Capital Management Llc | 13.14% | 3,481,283 | $41,358,000 | $63,498,602 | +$22,140,602 | +53.53% | |
| State Street Corp | 0.00% | 3,163,139 | $37,578,091 | $57,695,655 | +$20,117,564 | +53.54% | |
| Edenbrook Capital, Llc | 17.00% | 2,798,036 | $33,240,667 | $51,036,177 | +$17,795,510 | +53.54% | |
| Granahan Investment Management, Llc | 1.47% | 2,553,413 | $30,334,546 | $46,574,253 | +$16,239,707 | +53.54% | |
| Ophir Asset Management Pty Ltd | 2.93% | 2,118,016 | $25,162,030 | $38,632,612 | +$13,470,582 | +53.54% | |
| 325 Capital Llc | 8.68% | 2,005,387 | $23,823,998 | $36,578,259 | +$12,754,261 | +53.54% | |
| Kennedy Capital Management Llc | 0.44% | 1,753,542 | $20,832,079 | $31,984,606 | +$11,152,527 | +53.54% | |
| Jane Street Group, Llc | 0.02% | 1,668,160 | $19,817,740 | $30,427,238 | +$10,609,498 | +53.54% | |
| No Street Gp Lp | 1.29% | 1,628,248 | $19,343,586 | $29,699,244 | +$10,355,658 | +53.54% | |
| Schonfeld Strategic Advisors Llc | 0.16% | 1,605,041 | $19,067,886 | $29,275,948 | +$10,208,062 | +53.54% | |
| Goldman Sachs Group Inc | 0.00% | 1,500,852 | $17,830,121 | $27,375,540 | +$9,545,419 | +53.54% | |
| Balyasny Asset Management L.P. | 0.04% | 1,500,443 | $17,825,263 | $27,368,080 | +$9,542,817 | +53.54% | |
| Royce & Associates Lp | 0.16% | 1,365,489 | $16,222,009 | $24,906,519 | +$8,684,510 | +53.54% | |
| Maestria Partners Llc | 5.91% | 1,363,505 | $16,198,439 | $24,870,331 | +$8,671,892 | +53.54% | |
| Blue Grotto Capital, Llc | 1.82% | 1,328,782 | $15,785,930 | $24,236,984 | +$8,451,054 | +53.54% | |
| Northern Trust Corp | 0.00% | 1,322,571 | $15,712,144 | $24,123,695 | +$8,411,551 | +53.54% | |
| Victory Capital Management Inc | 0.01% | 1,266,522 | $15,046,282 | $23,101,361 | +$8,055,079 | +53.54% | |
| Grizzlyrock Capital, Llc | 11.65% | 1,238,680 | $14,715,518 | $22,593,523 | +$7,878,005 | +53.54% | |
| Millennium Management Llc | 0.01% | 1,234,457 | $14,665,349 | $22,516,496 | +$7,851,147 | +53.54% | |
| Charles Schwab Investment Management Inc | 0.00% | 1,180,431 | $14,023,520 | $21,531,061 | +$7,507,541 | +53.54% | |
| Bank Of New York Mellon Corp | 0.00% | 1,138,217 | $13,522,019 | $20,761,078 | +$7,239,059 | +53.54% | |
| Bank Of America Corp | 0.00% | 1,125,196 | $13,367,328 | $20,523,575 | +$7,156,247 | +53.54% | |
| Citadel Advisors Llc | 0.01% | 1,052,908 | $12,508,547 | $19,205,042 | +$6,696,495 | +53.54% | |
| Vanguard Fiduciary Trust Co | 0.00% | 997,082 | $11,845,334 | $18,186,776 | +$6,341,442 | +53.54% | |
| Meros Investment Management, Lp | 5.11% | 992,351 | $11,789,130 | $18,100,482 | +$6,311,352 | +53.54% | |
| Morgan Stanley | 0.00% | 926,819 | $11,010,613 | $16,905,179 | +$5,894,566 | +53.54% | |
| Kopion Asset Management, Llc | 7.91% | 855,904 | $10,168,140 | $15,611,689 | +$5,443,549 | +53.54% | |
| Man Group Plc | 0.02% | 663,957 | $7,887,809 | $12,110,576 | +$4,222,767 | +53.54% | |
| Qube Research & Technologies Ltd | 0.01% | 661,057 | $7,853,357 | $12,057,680 | +$4,204,323 | +53.54% | |
| Oberweis Asset Management Inc/ | 0.23% | 647,600 | $7,693,488 | $11,812,224 | +$4,118,736 | +53.54% | |
| Picton Mahoney Asset Management | 0.08% | 643,078 | $7,639,767 | $11,729,743 | +$4,089,976 | +53.54% | |
| Silvercrest Asset Management Group Llc | 0.05% | 616,084 | $7,319,078 | $11,237,372 | +$3,918,294 | +53.54% | |
| Park West Asset Management Llc | 0.63% | 598,380 | $7,108,754 | $10,914,451 | +$3,805,697 | +53.54% | |
| Nomura Asset Management Co Ltd | 0.02% | 593,900 | $7,055,532 | $10,832,736 | +$3,777,204 | +53.54% | |
| Centerbook Partners Lp | 0.36% | 564,156 | $6,702,173 | $10,290,205 | +$3,588,032 | +53.54% | |
| King Luther Capital Management Corp | 0.03% | 531,066 | $6,309,064 | $9,686,644 | +$3,377,580 | +53.54% | |
| Capital World Investors | 0.00% | 456,672 | $5,425,263 | $8,329,697 | +$2,904,434 | +53.54% | |
| Qvt Financial Lp | 0.43% | 453,910 | $5,392,451 | $8,279,318 | +$2,886,867 | +53.54% | |
| Ubs Group Ag | 0.00% | 450,349 | $5,350,146 | $8,214,366 | +$2,864,220 | +53.54% |
Frequently asked questions about MGNI
Who owns the most MGNI stock?
The largest holders of MGNI 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 MAGNITE INC (MGNI).
Is MGNI widely held by superinvestors?
Many widely followed stocks like MGNI appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly MGNI 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.