Latest Period
Q4 2025
- Info
- Insider Trading
- Financials
- Holders
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
299
Shares (Excl. Options)
136,580,430
Price
$16.23
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- Type / Class
- Equity / Common Stock
- Symbol
- MGNI on Nasdaq
- Shares outstanding
- 143,558,767
- Price per share
- $11.88
- All holders as of 31 Dec 2025
- Q4 2025
- Total 13F shares
- 136,580,430
- Total reported value
- $2,216,806,229
- % of total 13F portfolios
- 0.01%
- Share change
- -1,888,657
- Value change
- -$66,124,177
- Number of holders
- 299
- Price from insider filings
- $11.88
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors
Quick Takeaways
- MGNI - MAGNITE, INC. - Common Stock is tracked under CUSIP 55955D100.
- 299 institutions reported positions in Q4 2025.
- 3 significant owners is listed from Schedule 13D/13G reporting.
What Changed
- Holder count moved from 299 to 28 between Q4 2025 and Q1 2026.
- Reported value moved from $2,216,806,229 to $31,999,163.
Why This Matters
- 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.
Source Evidence
Source: SEC Form 13F
Open SEC Evidence
Latest holder context comes from 299 institutions filings for Q4 2025.
Investment Quick Answers
What is CUSIP 55955D100?
CUSIP 55955D100 identifies MGNI - MAGNITE, INC. - Common Stock in SEC 13F datasets.
Where can I see the latest institutional holders?
Review the Q4 2025 holders report and the ownership history table below.
Next ownership checks
Use the next link that matches the question you still need to answer about this security.
- Latest 13F filings when you want to inspect fresh institutional portfolio moves.
- Latest Schedule 13D/13G reports when you need large-owner changes outside the 13F cycle.
- All institutional ownership pages to compare this security with other holder-history pages.
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 55955D100:
Significant Owners of MAGNITE, INC. - Common Stock (MGNI) based on Schedule 13D/G filings
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| Capital Research Global Investors | 9% | +82% | $207,887,450 | +$95,533,217 | 12,920,289 | +85% | Capital Research Global Investors | 31 Dec 2025 |
| WELLINGTON MANAGEMENT GROUP LLP | 6% | $138,844,439 | 8,629,238 | Wellington Management Group LLP | 31 Dec 2025 | |||
| FMR LLC | 5.7% | -54% | $115,617,607 | -$129,484,064 | 8,124,920 | -53% | FMR LLC | 28 Nov 2025 |
As of 31 Dec 2025, 299 institutional investors reported holding 136,580,430 shares of MAGNITE, INC. - Common Stock (MGNI). This represents 95% of the company’s total 143,558,767 outstanding shares.
Top 25 Institutional Shareholders
The largest institutional shareholders of MAGNITE, INC. - Common Stock (MGNI) together control 73% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| VANGUARD GROUP INC | 10% | 14,802,630 | +1% | 0% | $240,246,684 |
| Capital Research Global Investors | 9% | 12,920,289 | +85% | 0.04% | $209,696,290 |
| BlackRock, Inc. | 8.1% | 11,593,249 | +1.6% | 0% | $188,158,440 |
| WELLINGTON MANAGEMENT GROUP LLP | 6% | 8,629,238 | +68% | 0.02% | $140,052,533 |
| FMR LLC | 4.7% | 6,701,174 | -61% | 0.01% | $108,760,051 |
| AMERICAN CENTURY COMPANIES INC | 3.7% | 5,286,928 | +15% | 0.04% | $85,806,867 |
| Boston Partners | 2.9% | 4,108,893 | -7.6% | 0.07% | $66,596,374 |
| DIMENSIONAL FUND ADVISORS LP | 2.5% | 3,615,820 | +1.4% | 0.01% | $58,687,197 |
| Nuveen, LLC | 2.5% | 3,531,108 | +14% | 0.02% | $57,309,883 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.4% | 3,434,062 | +1% | 0% | $55,744,057 |
| STATE STREET CORP | 2.2% | 3,141,991 | +0.49% | 0% | $50,994,514 |
| Granahan Investment Management, LLC | 2.2% | 3,115,930 | -20% | 2.2% | $50,571,544 |
| Nine Ten Capital Management LLC | 2.1% | 3,003,583 | +5.1% | 15% | $48,748,000 |
| Edenbrook Capital, LLC | 1.9% | 2,788,036 | +32% | 19% | $45,249,825 |
| Ophir Asset Management Pty Ltd | 1.7% | 2,384,187 | 4.3% | $38,695,355 | |
| 325 CAPITAL LLC | 1.4% | 2,005,387 | +208% | 11% | $32,547,431 |
| MORGAN STANLEY | 1.3% | 1,862,538 | -9% | 0% | $30,228,995 |
| GOLDMAN SACHS GROUP INC | 1.2% | 1,761,037 | -26% | 0% | $28,581,630 |
| Blue Grotto Capital, LLC | 1.1% | 1,628,782 | +5.2% | 2.7% | $26,435,132 |
| No Street GP LP | 1% | 1,475,000 | 1.6% | $23,939,250 | |
| KENNEDY CAPITAL MANAGEMENT LLC | 1% | 1,435,970 | +18% | 0.49% | $23,305,793 |
| Maestria Partners LLC | 0.95% | 1,363,505 | +19% | 6.5% | $22,129,686 |
| NORTHERN TRUST CORP | 0.89% | 1,272,068 | -6.8% | 0% | $20,645,664 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 0.83% | 1,187,501 | -2.5% | 0% | $19,273,141 |
| Bank of New York Mellon Corp | 0.82% | 1,183,318 | -6.2% | 0% | $19,205,245 |
Institutional Holders of MAGNITE, INC. - Common Stock (MGNI) across Reporting Periods
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 2,693,532 | $31,999,163 | +$2,009,007 | $11.88 | 28 |
| 2025 Q4 | 136,580,430 | $2,216,806,229 | -$66,124,177 | $16.23 | 299 |
| 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 | |
| 2019 Q4 | 203 | $7,000 | $34.48 | 1 | |
| 2019 Q3 | 203 | $7,000 | $34.48 | 1 | |
| 2019 Q2 | 203 | $7,000 | $34.48 | 1 | |
| 2019 Q1 | 203 | $7,000 | $34.48 | 1 |