X0508 4 2024-01-02 0 0001595974 MAGNITE, INC. MGNI 0001966857 Buonasera David C/O MAGNITE, INC. 1250 BROADWAY, 15TH FLOOR NEW YORK NY 10001 0 1 0 0 Chief Technology Officer 0 Common Stock 2024-01-02 4 A 0 85058 0.00 A 290639 D Performance Stock Units 2024-01-02 4 A 0 30339 0.00 A Common Stock 30339 30339 D Represents restricted stock units that vest as follows: 23,037 on February 15, 2025, 5,316 on each May 15, August 15, November 15, and February 15 thereafter until November 15, 2027 and 3,545 on February 15, 2028, 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. Each performance stock unit ("PSU") represents a contingent right to receive on vesting one share of the Issuer's common stock. The PSUs will generally vest on the three-year anniversary of the grant date of the award subject to the Reporting Person's continued service through such date. The number of shares vested will be determined based on the Issuer's total stockholder return ("TSR") relative to the TSRs of the companies in the Russell 2000 index for the three year-period beginning January 1, 2024, as well as certain interim measurements based on relative TSR for the one-year and two-year periods beginning on January 1, 2024. The number of PSUs reported in column 5 reflects the target number of PSUs subject to the award. The award is eligible to vest as to 0% to 150% of the target number of PSUs. /s/ Aaron Saltz, attorney-in-fact 2024-01-04