X0609 4 2026-10-01 0 0001595974 MAGNITE, INC. MGNI 0001778484 Gephart Brian false C/O MAGNITE, INC. 1250 BROADWAY, 9TH FLOOR NEW YORK NY 10001 0 1 0 0 CHIEF FINANCIAL OFFICER 0 Common Stock 2026-10-01 4 A 0 64682 0 A 167010 D Represents restricted stock units that vest as follows: 17,518 on November 15, 2027, 4,043 on each February 15, May 15, August 15, and November 15 thereafter until August 15, 2030 and 2,691 on November 15, 2030, subject to continued service to the Issuer through each vesting date. This equity grant may be subject to accelerated vesting in the event the Reporting Person's employment is terminated under certain circumstances. Equity grant under the Company's Amended and Restated 2014 Equity Incentive Plan. /s/ Aaron Saltz, attorney-in-fact 2026-10-02