United States securities and exchange commission logo June 14, 2023 David Day Chief Financial Officer Magnite, Inc. 1250 Broadway, 15th Floor, New York, New York 10001 Re: Magnite, Inc. Form 10-K for period ended December 31, 2022 filed on February 22, 2023 File No. 001-36384 Dear David Day: We have completed our review of your filing. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Sincerely, Division of Corporation Finance Office of Technology