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Ken Griffin's Magnite, Inc. (MGNI) position

Yes: as of Q1 2026, Ken Griffin holds 1.1M shares of MGNI worth $12M (0.0% of the disclosed portfolio). Held since at least Q1 2021; that opening coverage snapshot is not counted as a purchase.
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Current value
$12M
Shares held
1.1M
% of portfolio
0.0%
Est. average buy price (i)
$14.68
est. since Q3 2023
Quarter-end price
$11.84

Estimated trade prices

Average price in quarters with purchases
$18.29
Average prices in quarters with sales
  • Q3 2025: $23.61 (666K shares sold)
  • Q4 2024: $14.67 (392K shares sold)
  • Q2 2024: $10.93 (127K shares sold)
  • Q4 2023: $7.90 (173K shares sold)
  • Q2 2023: $11.13 (575K shares sold)
  • Q3 2022: $8.05 (608K shares sold)
  • Q4 2021: $22.54 (291K shares sold)
  • Q3 2021: $30.09 (224K shares sold)

MGNI price vs Griffin's position

1Y 3Y 5Y MAX
Dates
$6$20$4020222023202420252026Sold 224K shares (14.9%) · Q3 2021. Average closing price $30.09 · Price range $24.30–$34.68224KsharessoldSold 291K shares (22.7%) · Q4 2021. Average closing price $22.54 · Price range $16.60–$30.58291KsharessoldAdded 39K shares (4.0%) · Q1 2022. Average closing price $13.49 · Price range $10.53–$17.8339KsharespurchasedAdded 441K shares (42.8%) · Q2 2022. Average closing price $10.72 · Price range $8.88–$14.22441KsharespurchasedSold 608K shares (41.3%) · Q3 2022. Average closing price $8.05 · Price range $6.35–$9.80608KsharessoldAdded 225K shares (35.2%) · Q1 2023. Average closing price $10.65 · Price range $8.40–$13.76225KsharespurchasedSold 575K shares (66.4%) · Q2 2023. Average closing price $11.13 · Price range $8.41–$13.85575KsharessoldSold 173K shares (31.3%) · Q4 2023. Average closing price $7.90 · Price range $6.51–$9.84173KsharessoldAdded 36K shares (9.5%) · Q1 2024. Average closing price $9.99 · Price range $8.69–$12.2336KsharespurchasedSold 127K shares (30.5%) · Q2 2024. Average closing price $10.93 · Price range $8.46–$13.87127KsharessoldAdded 413K shares (142.7%) · Q3 2024. Average closing price $13.63 · Price range $12.37–$15.84413KsharespurchasedSold 392K shares (55.8%) · Q4 2024. Average closing price $14.67 · Price range $11.91–$18.00392KsharessoldAdded 283K shares (91.1%) · Q1 2025. Average closing price $15.94 · Price range $11.41–$21.17283KsharespurchasedAdded 242K shares (40.8%) · Q2 2025. Average closing price $14.73 · Price range $9.00–$24.12242KsharespurchasedSold 666K shares (79.7%) · Q3 2025. Average closing price $23.61 · Price range $21.75–$26.52666KsharessoldAdded 375K shares (221.0%) · Q4 2025. Average closing price $16.60 · Price range $13.13–$20.39375KsharespurchasedAdded 509K shares (93.4%) · Q1 2026. Average closing price $13.40 · Price range $11.20–$16.88509Ksharespurchased← Earlier —1 purchase
Average closing price · filing quarter
$13.40
Price range · filing quarter
$11.20 – $16.88
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Every quarterly change

Quarter Action Shares change Est. value change Δ Own Shares held Filing date
Q1 2026 Added +509K +$6.8M +93.4% 1.1M May 15, 2026
Q4 2025 Added +375K +$6.2M +221.0% 544K Feb 17, 2026
Q3 2025 Reduced −666K −$16M −79.7% 170K Nov 14, 2025
Q2 2025 Added +242K +$3.6M +40.8% 835K Aug 14, 2025
Q1 2025 Added +283K +$4.5M +91.1% 593K May 15, 2025
Q4 2024 Reduced −392K −$5.8M −55.8% 310K Feb 14, 2025
Q3 2024 Added +413K +$5.6M +142.7% 703K Nov 14, 2024
Q2 2024 Reduced −127K −$1.4M −30.5% 289K Aug 14, 2024
Q1 2024 Added +36K +$363K +9.5% 417K May 15, 2024
Q4 2023 Reduced −173K −$1.4M −31.3% 380K Feb 14, 2024
Q3 2023 First covered – – – 554K Nov 14, 2023
Q2 2023 Reduced −575K −$6.4M −66.4% 290K Aug 14, 2023
Q1 2023 Added +225K +$2.4M +35.2% 865K May 15, 2023
Q4 2022 First covered – – – 640K Feb 14, 2023
Q3 2022 Reduced −608K −$4.9M −41.3% 864K Nov 14, 2022
Q2 2022 Added +441K +$4.7M +42.8% 1.5M Aug 15, 2022
Q1 2022 Added +39K +$529K +4.0% 1.0M May 16, 2022
Q4 2021 Reduced −291K −$6.5M −22.7% 992K Feb 14, 2022
Q3 2021 Reduced −224K −$6.7M −14.9% 1.3M Nov 15, 2021
Q2 2021 Added +778K +$26M +106.7% 1.5M Aug 16, 2021
Q1 2021 First covered – – – 729K May 21, 2021
Data through Q1 2026 · filed May 15, 2026
21 grouped rows from 21 quarters

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Common questions

Does Ken Griffin own MGNI?

Yes. As of Q1 2026, Ken Griffin disclosed 1.1M shares of MGNI, worth $12M. All figures come from SEC 13F filings for Q1 2026, the latest disclosed quarter.

When did Ken Griffin buy MGNI?

Ken Griffin held MGNI since at least Q1 2021, when this filing coverage begins; the opening snapshot is not a disclosed purchase. All figures come from SEC 13F filings for Q1 2026, the latest disclosed quarter.

Did Ken Griffin sell MGNI?

The quarter-by-quarter table above shows each sale and reduction Ken Griffin disclosed in MGNI. All figures come from SEC 13F filings for Q1 2026, the latest disclosed quarter.

How many shares of MGNI does Ken Griffin own?

Ken Griffin disclosed 1.1M shares of MGNI as of Q1 2026. All figures come from SEC 13F filings for Q1 2026, the latest disclosed quarter.

What price did Ken Griffin pay for MGNI?

Ken Griffin began building the MGNI position before our 13F history starts, so an exact average buy price cannot be estimated without understating it. All figures come from SEC 13F filings for Q1 2026, the latest disclosed quarter.

How are the estimated trade prices calculated?

13F filings disclose quarter-end holdings, not trade dates or execution prices. These estimates use each covered quarter's average market price; the add average excludes the opening position and quarters without price data. All figures come from SEC 13F filings for Q1 2026, the latest disclosed quarter.