Ticker · CUSIP 55955D100
Holders (tracked)
16
Combined shares
12,396,725
Combined value
$189.66M
Last close
$13.64
Quarter
2025Q4
Tracked holders · last 8 quarters
Flat over the last 8 quarters.
Price is -10.8% vs the avg quarter-end implied price across tracked holders.
SEC event timeline
24 events
- Ken Griffin (Citadel Advisors) added2026-02-17+374,757 shares · 2025Q413F
- D.E. Shaw & Co. exited2026-02-17−211,433 shares · 2025Q413F
- Two Sigma Investments added2026-02-17+62,981 shares · 2025Q413F
- Izzy Englander (Millennium Mgmt) trimmed2026-02-17−652,605 shares · 2025Q413F
- +34,674 shares · 2025Q413F
- Wellington Management added2026-02-17+3,484,689 shares · 2025Q413F
- AQR Capital Management added2026-02-17+49,464 shares · 2025Q413F
- Steve Cohen (Point72) exited2026-02-17−305,316 shares · 2025Q413F
- T. Rowe Price trimmed2026-02-17−1,836,010 shares · 2025Q413F
- −484 shares · 2025Q413F
- Mario Gabelli (GAMCO) trimmed2026-02-05−11,990 shares · 2025Q413F
- −279,000 shares · 2025Q413F
- AQR Capital Management added2025-11-14+27,111 shares · 2025Q313F
- +676,349 shares · 2025Q313F
- Steve Cohen (Point72) opened position2025-11-14+305,316 shares · 2025Q313F
- Two Sigma Investments added2025-11-14+62,605 shares · 2025Q313F
- D.E. Shaw & Co. added2025-11-14+179,486 shares · 2025Q313F
- T. Rowe Price added2025-11-14+2,429,904 shares · 2025Q313F
- Wellington Management trimmed2025-11-14−303,288 shares · 2025Q313F
- Norges Bank (Norway SWF) exited2025-11-13−108,716 shares · 2025Q313F
- +145,671 shares · 2025Q313F
- Mario Gabelli (GAMCO) trimmed2025-11-12−3,114 shares · 2025Q313F
- −42,676 shares · 2025Q313F
- Norges Bank (Norway SWF) trimmed2025-11-12−121,728 shares · 2024Q313F
Insider activity
No insider transactions in the last 30 days.
Follow-the-investor returns
If you'd copied each holder of MGNI…
Cost basis inferred from 13F share-delta history. Sorted by % return on the position they're still holding.
| Investor | First in | Cost basis | Return | Position value today |
|---|---|---|---|---|
| T. Rowe Price | 2020Q4 | $0.59 | +2220.9% | $9.7M |
| Wellington Management | 2020Q3 | $12.76 | +6.9% | $117.7M |
| First Eagle Investment Management | 2022Q2 | $13.18 | +3.5% | $4.0M |
| Mario Gabelli (GAMCO) | 2024Q2 | $13.82 | -1.3% | $607K |
| Paul Tudor Jones (Tudor Investment) | 2020Q4 | $15.97 | -14.6% | $1.2M |
| Paul Tudor Jones (Tudor Investment) | 2020Q4 | $15.97 | -14.6% | $1.2M |
| Paul Tudor Jones (Tudor Investment) | 2020Q4 | $15.97 | -14.6% | $1.2M |
| Ken Griffin (Citadel Advisors) | 2020Q3 | $19.18 | -28.9% | $7.4M |
| Ken Griffin (Citadel Advisors) | 2020Q3 | $19.18 | -28.9% | $7.4M |
| Ken Griffin (Citadel Advisors) | 2020Q3 | $19.18 | -28.9% | $7.4M |
| AQR Capital Management | 2020Q3 | $19.83 | -31.2% | $1.3M |
| Izzy Englander (Millennium Mgmt) | 2020Q3 | $20.08 | -32.1% | $324K |
| Izzy Englander (Millennium Mgmt) | 2020Q3 | $20.08 | -32.1% | $324K |
| Steve Cohen (Point72) | 2024Q1 | $20.52 | -33.5% | $321K |
| Two Sigma Investments | 2021Q1 | $20.64 | -33.9% | $5.0M |
| Ray Dalio (Bridgewater Associates) | 2025Q3 | $21.78 | -37.4% | $2.0M |
Who moved on this name in 2025Q4
13F transactions reported for the latest quarter, grouped by direction.
New positions1
- Paul Tudor Jones (Tudor Investment)+34,674$563K
Added to4
- Wellington Management+3,484,689$56.6M
- Ken Griffin (Citadel Advisors)+374,757$6.1M
- Two Sigma Investments+62,981$1.0M
- AQR Capital Management+49,464$803K
Trimmed5
- Izzy Englander (Millennium Mgmt)−652,605$10.6M
- First Eagle Investment Management−279,000$4.5M
- Mario Gabelli (GAMCO)−11,990$195K
- T. Rowe Price−1,836,010$30K
- Ray Dalio (Bridgewater Associates)−484$8K
Exited2
- Steve Cohen (Point72)−305,316$6.6M
- D.E. Shaw & Co.−211,433$4.6M
Institutional ownership over time
Distinct super-investors holding this ticker · combined dollar value, by quarter.
| Quarter | Holders | Combined value |
|---|---|---|
| 2022Q1 | 11 | $15.90B |
| 2022Q2 | 13 | $10.66B |
| 2022Q3 | 13 | $7.9M |
| 2022Q4 | 13 | $139.5M |
| 2023Q1 | 11 | $122.8M |
| 2023Q2 | 12 | $190.0M |
| 2023Q3 | 11 | $92.1M |
| 2023Q4 | 9 | $114.6M |
| 2024Q1 | 11 | $156.8M |
| 2024Q2 | 12 | $191.2M |
| 2024Q3 | 12 | $125.3M |
| 2024Q4 | 13 | $37.8M |
| 2025Q1 | 12 | $93.5M |
| 2025Q2 | 11 | $196.4M |
| 2025Q3 | 16 | $185.8M |
| 2025Q4 | 16 | $189.7M |
Who owns MGNI
16 super-investors · 2025Q4
Tracked stake
12.40M
shares
Combined value
$190M
% of shares outstanding
—
shares-out unknown
Quarter action mix
New3Added6Trim6Sold1
| # | Manager | Shares | Value |
|---|---|---|---|
| 1 | Wellington Management | 8.63M | $140M |
| 2 | Ken Griffin Citadel Advisors | 760.2K | $12M |
| 3 | Ken Griffin Citadel Advisors | 544.3K | $9M |
| 4 | Ken Griffin Citadel Advisors | 438.2K | $7M |
| 5 | Two Sigma Investments | 363.4K | $6M |
| 6 | First Eagle Investment Management | 296.4K | $5M |
| 7 | Paul Tudor Jones Tudor Investment | 177.1K | $3M |
| 8 | Ray Dalio Bridgewater Associates | 145.2K | $2M |
| 9 | AQR Capital Management | 97.5K | $2M |
| 10 | Paul Tudor Jones Tudor Investment | 89.4K | $1M |
| 11 | Mario Gabelli GAMCO | 44.5K | $722K |
| 12 | Paul Tudor Jones Tudor Investment | 34.7K | $563K |
| 13 | Izzy Englander Millennium Mgmt | 23.7K | $385K |
| 14 | Steve Cohen Point72 | 23.5K | $381K |
| 15 | Izzy Englander Millennium Mgmt | 17.8K | $289K |
| 16 | T. Rowe Price | 711.5K | $12K |
Recent moves
20 transactions
- +49,464 · 2025Q4
- −652,605 · 2025Q4
- TRIMT. Rowe Price−1,836,010 · 2025Q4
- +62,981 · 2025Q4
- −305,316 · 2025Q4
- SOLDD.E. Shaw & Co.−211,433 · 2025Q4
- +34,674 · 2025Q4
- +3,484,689 · 2025Q4
- +374,757 · 2025Q4
- −484 · 2025Q4
- −11,990 · 2025Q4
- −279,000 · 2025Q4
- +305,316 · 2025Q3
- +62,605 · 2025Q3
- +676,349 · 2025Q3
- +179,486 · 2025Q3
- +2,429,904 · 2025Q3
- −303,288 · 2025Q3
- +27,111 · 2025Q3
- −108,716 · 2025Q3
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