X0609 4 2026-06-08 0001595974 MAGNITE, INC. MGNI 0001350876 Knopper Douglas S false C/O MAGNITE, INC. 1250 BROADWAY, 9TH FLOOR NEW YORK NY 10001 true false false false true Common Stock 2026-06-08 4 A false 13798 0 A 173913 D Common Stock 2026-06-10 4 S false 10766 15.73 D 163147 D Represents restricted stock units that vest in full on the earliest of (i) June 8, 2027, (ii) the date of the 2027 annual meeting of the Issuer's stockholders, or (iii) a change of control of the Issuer. Granted as compensation for services. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 12, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.29 to $15.90, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4. /s/ Aaron Saltz, attorney-in-fact 2026-06-10