Magnite, Inc.
MX ˙ BMV ˙ US55955D1000
SecurityMX:MGNI / Magnite, Inc.
InstitutionMillennium Management Llc
ManagerIsrael Englander
Latest Disclosed Ownership1,234,457 shares
Latest Disclosed Value $ 14,665,349
Millennium Management Llc ownership in MGNI / Magnite, Inc.

On May 15, 2026 - Millennium Management Llc filed a 13F-HR form disclosing ownership of 1,234,457 shares of Magnite, Inc. (MX:MGNI) valued at $14,665,349 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 23,744 shares of Magnite, Inc.. This represents a change in shares of 5,099.03% during the quarter.

Millennium Management Llc has a history of taking positions in derivatives of the underlying security (MGNI) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:MGNI / Magnite, Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F MAGNITE COM 55955D100 1,234,457 1,210,713 5,099.03 14,665 3,709.09 0.0061
2026-02-17 2025-12-31 13F MAGNITE COM 55955D100 23,744 -652,605 -96.49 385 -97.39 0.0002
2025-11-14 2025-09-30 13F MAGNITE COM 55955D100 676,349 676,349 14,731 0.0063
2025-08-14 2025-06-30 13F MAGNITE COM 55955D100 0 -434,479 -100.00 0 -100.00
2025-05-15 2025-03-31 13F MAGNITE COM 55955D100 434,479 215,513 98.42 4,957 42.24 0.0026
2025-02-14 2024-12-31 13F MAGNITE COM 55955D100 218,966 66,737 43.84 3,486 65.32 0.0017
2024-11-14 2024-09-30 13F MAGNITE COM 55955D100 152,229 118,511 351.48 2,108 370.54 0.0010
2024-08-14 2024-06-30 13F MAGNITE COM 55955D100 33,718 18,579 122.72 448 176.54 0.0002
2024-05-15 2024-03-31 13F MAGNITE COM 55955D100 15,139 -289,953 -95.04 163 -94.31 0.0001
2024-02-14 2023-12-31 13F MAGNITE COM 55955D100 305,092 -220,229 -41.92 2,850 -28.06 0.0012
2023-11-14 2023-09-30 13F MAGNITE COM 55955D100 525,321 481,931 1,110.70 3,961 568.92 0.0020
2023-08-14 2023-06-30 13F MAGNITE COM 55955D100 43,390 43,390 592 0.0003
2023-05-15 2023-03-31 13F MAGNITE COM 55955D100 0 -30,943 -100.00 0 -100.00
2023-02-14 2022-12-31 13F MAGNITE COM 55955D100 30,943 -29,686 -48.96 328 -17.59 0.0002
2022-11-14 2022-09-30 13F MAGNITE COM 55955D100 60,629 -14,081 -18.85 398 -39.97 0.0002
2022-08-15 2022-06-30 13F MAGNITE COM 55955D100 74,710 -423,720 -85.01 663 -89.93 0.0004
2022-05-16 2022-03-31 13F MAGNITE COM 55955D100 498,430 -553,441 -52.61 6,584 -64.23 0.0035
2022-02-14 2021-12-31 13F MAGNITE COM 55955D100 1,051,871 652,786 163.57 18,408 64.74 0.0094
2021-11-15 2021-09-30 13F MAGNITE COM 55955D100 399,085 -250,972 -38.61 11,174 -49.20 0.0067
2021-08-16 2021-06-30 13F MAGNITE COM 55955D100 650,057 272,357 72.11 21,998 39.97 0.0135
2021-05-17 2021-03-31 13F MAGNITE COM 55955D100 377,700 -776,130 -67.27 15,716 -55.65 0.0112
2021-02-16 2020-12-31 13F MAGNITE COM 55955D100 1,153,830 1,110,488 2,562.15 35,434 11,672.09 0.0256
2020-11-16 2020-09-30 13F MAGNITE COM 55955D100 43,342 43,342 301 0.0004
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F MAGNITE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-17 2025-12-31 13F MAGNITE COM Call 17,800 -35.04 289 -51.68 n/a n/a n/a
2025-11-14 2025-09-30 13F MAGNITE COM Call 27,400 597 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2025-05-15 2025-03-31 13F MAGNITE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-14 2024-12-31 13F MAGNITE COM Put 15,700 0.00 250 14.75 n/a n/a n/a
2024-11-14 2024-09-30 13F MAGNITE COM Put 15,700 217 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.