Latest Period
Q1 2026
Security Snapshot
MAGNITE, INC. - Common Stock (MGNI) Institutional Ownership
CUSIP: 55955D100
13F Institutional Holders and Ownership History from Q1 2019 to Q1 2026
Institutions Reporting
296
Shares (Excl. Options)
131,063,012
Price
$11.88
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- Security type / class
- Equity / Common Stock
- Symbol
- MGNI on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 131,063,012
- Total 13F value
- $1,557,738,986
- Portfolio coverage rank
- 0.01%
- Share change
- -5,875,280
- Value change
- -$97,684,432
- Number of holders
- 296
- Shares outstanding
- 143,436,829
- SEC-reported price per share
- $12.91
- Insider filing price
- $12.91
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
3 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- MGNI - MAGNITE, INC. - Common Stock is tracked under CUSIP 55955D100.
- 296 institutions reported positions in Q1 2026.
- 5 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 302 to 296 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $2,218,533,410 to $1,557,738,986.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 296 institutions filings for Q1 2026.
Security key
55955D100
Latest holder period
Q1 2026
13F holders
296
13D/G owners
5
CIK / CUSIP context first
Open Q1 2026 holders
MGNI full holder history
MAGNITE, INC. SEC filings
MAGNITE, INC. company facts
MAGNITE, INC. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 55955D100:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
5
Security
MGNI
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| WELLINGTON MANAGEMENT GROUP LLP | 6% | $138,844,439 | 8,629,238 | Wellington Management Group LLP | 31 Dec 2025 | |||
| VANGUARD PORTFOLIO MANAGEMENT LLC | 5.4% | $93,256,456 | 7,849,870 | Vanguard Portfolio Management | 31 Mar 2026 | |||
| VANGUARD CAPITAL MANAGEMENT LLC | 5% | $86,525,949 | 7,283,329 | Vanguard Capital Management | 31 Mar 2026 | |||
| Capital Research Global Investors | 3.5% | -61% | $60,695,294 | -$95,511,000 | 5,020,289 | -61% | Capital Research Global Investors | 31 Mar 2026 |
| FMR LLC | 3.1% | -43% | $54,494,691 | -$43,735,587 | 4,507,419 | -45% | FMR LLC | 31 Mar 2026 |
As of 31 Mar 2026, 296 institutional investors reported holding 131,063,012 shares of MAGNITE, INC. - Common Stock (MGNI). This represents 91% of the company’s total 143,436,829 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
65%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| BlackRock, Inc. | 8.1% | 11,657,496 | +0.55% | 0% | $138,491,059 |
| WELLINGTON MANAGEMENT GROUP LLP | 6.4% | 9,191,077 | +6.5% | 0.02% | $109,189,995 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 5.4% | 7,726,205 | 0% | 0% | $91,787,315 |
| VANGUARD CAPITAL MANAGEMENT LLC | 4.3% | 6,190,403 | 0% | 0% | $73,541,988 |
| Capital Research Global Investors | 3.5% | 5,020,289 | -61% | 0.01% | $59,641,033 |
| Boston Partners | 3.3% | 4,719,863 | +15% | 0.06% | $56,078,770 |
| AMERICAN CENTURY COMPANIES INC | 3.2% | 4,626,816 | -12% | 0.03% | $54,966,590 |
| FMR LLC | 3.1% | 4,507,419 | -33% | 0% | $53,548,133 |
| DIMENSIONAL FUND ADVISORS LP | 2.8% | 3,983,674 | +10% | 0.01% | $47,321,837 |
| Nuveen, LLC | 2.5% | 3,590,025 | +1.7% | 0.01% | $42,649,497 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.5% | 3,553,790 | +3.5% | 0% | $42,226,958 |
| Nine Ten Capital Management LLC | 2.4% | 3,481,283 | +16% | 13% | $41,358,000 |
| STATE STREET CORP | 2.2% | 3,163,139 | +0.67% | 0% | $37,578,091 |
| Edenbrook Capital, LLC | 2% | 2,798,036 | +0.36% | 17% | $33,240,667 |
| Granahan Investment Management, LLC | 1.8% | 2,553,413 | -18% | 1.5% | $30,334,546 |
| Ophir Asset Management Pty Ltd | 1.5% | 2,118,016 | -11% | 2.9% | $25,162,030 |
| 325 CAPITAL LLC | 1.4% | 2,005,387 | 0% | 8.7% | $23,823,998 |
| KENNEDY CAPITAL MANAGEMENT LLC | 1.2% | 1,753,542 | +22% | 0.44% | $20,832,079 |
| JANE STREET GROUP, LLC | 1.2% | 1,668,160 | +339% | 0.02% | $19,817,740 |
| No Street GP LP | 1.1% | 1,628,248 | +10% | 1.3% | $19,343,586 |
| Schonfeld Strategic Advisors LLC | 1.1% | 1,605,041 | +106% | 0.16% | $19,067,886 |
| GOLDMAN SACHS GROUP INC | 1% | 1,500,852 | -15% | 0% | $17,830,121 |
| Balyasny Asset Management L.P. | 1% | 1,500,443 | +72% | 0.04% | $17,825,263 |
| ROYCE & ASSOCIATES LP | 0.95% | 1,365,489 | +17% | 0.16% | $16,222,009 |
| Maestria Partners LLC | 0.95% | 1,363,505 | 0% | 5.9% | $16,198,439 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
29
Latest
Q1 2026
Rows shown
1-25 of 29
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 131,063,012 | $1,557,738,986 | -$97,684,432 | $11.88 | 296 |
| 2025 Q4 | 136,686,849 | $2,218,533,410 | -$66,065,895 | $16.23 | 302 |
| 2025 Q3 | 138,012,684 | $3,003,860,929 | -$207,225,719 | $21.78 | 313 |
| 2025 Q2 | 146,964,373 | $3,543,069,968 | +$406,190,715 | $24.12 | 285 |
| 2025 Q1 | 132,644,878 | $1,513,348,970 | +$97,506,469 | $11.41 | 290 |
| 2024 Q4 | 123,449,236 | $1,965,951,862 | +$42,368,020 | $15.92 | 283 |
| 2024 Q3 | 119,561,299 | $1,654,115,115 | +$216,068,704 | $13.85 | 279 |
| 2024 Q2 | 104,326,333 | $1,386,459,925 | +$39,957,238 | $13.29 | 266 |
| 2024 Q1 | 102,110,845 | $1,097,564,621 | -$5,361,702 | $10.75 | 230 |
| 2023 Q4 | 102,653,022 | $958,824,603 | -$4,019,427 | $9.34 | 215 |
| 2023 Q3 | 103,476,989 | $780,247,255 | -$17,837,826 | $7.54 | 208 |
| 2023 Q2 | 101,048,317 | $1,380,031,436 | +$74,884,448 | $13.65 | 217 |
| 2023 Q1 | 96,353,092 | $892,115,344 | +$22,211,875 | $9.26 | 217 |
| 2022 Q4 | 93,373,687 | $988,829,597 | -$97,935,020 | $10.59 | 228 |
| 2022 Q3 | 103,432,133 | $679,628,120 | +$93,907,627 | $6.57 | 201 |
| 2022 Q2 | 87,980,237 | $781,403,356 | -$17,395,213 | $8.88 | 214 |
| 2022 Q1 | 88,698,180 | $1,171,861,875 | -$35,248,615 | $13.21 | 215 |
| 2021 Q4 | 89,542,528 | $1,566,754,035 | -$140,798,799 | $17.50 | 238 |
| 2021 Q3 | 90,069,072 | $2,521,283,357 | +$118,150,307 | $28.00 | 270 |
| 2021 Q2 | 85,375,930 | $2,889,381,654 | -$89,507,112 | $33.84 | 264 |
| 2021 Q1 | 86,041,634 | $3,579,979,338 | +$418,396,545 | $41.61 | 271 |
| 2020 Q4 | 76,786,392 | $2,357,551,419 | +$83,965,902 | $30.71 | 235 |
| 2020 Q3 | 83,209,025 | $577,796,330 | +$477,632,041 | $6.94 | 168 |
| 2020 Q2 | 14,428,175 | $96,233,000 | +$96,233,000 | $6.67 | 10 |
| 2020 Q1 | 203 | $7,000 | $34.48 | 1 |