Magnite, Inc.
1250 Broadway, 15^th Floor
New York, New York 10001

The Rubicon Project, Inc.
12181 Bluff Creek Drive, 4th Floor
Los Angeles, California 90094

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS
TO BE HELD ON MAY 15, 2019JUNE 7, 2022

The annual meeting of stockholders of The Rubicon Project,Magnite, Inc. (the “company”) will be held on Tuesday, June 7, 2022, at the company’s headquarters, located at 12181 Bluff Creek Drive, 4th Floor, Los Angeles, California 90094, on Wednesday, May 15, 2019, at 12:2:00 noon localp.m. Eastern time, to consider and act upon the following matters:matters described below. In light of the ongoing coronavirus (COVID-19) pandemic, and out of an abundance of caution and appreciation for our stockholders, this year’s annual meeting will be a virtual meeting via live webcast on the Internet. You will be able to attend the annual meeting, view the list of our registered stockholders, vote and submit your questions during the meeting by visiting https://web.lumiagm.com/293659257 and entering the control number included on the Notice of Internet Availability or the proxy card or voting instruction form (if you received a printed copy of the proxy materials) that you receive. Beneficial owners should review the proxy materials and their voting instruction form or Notice of Internet Availability for information about how to vote in advance of and how to participate in the meeting. You will not be able to attend the annual meeting in person.

1.Election of three Class II directors to serve until the company’s 2025 annual meeting of stockholders and until their respective successors are duly elected and qualified.

2.Ratification of the selection of Deloitte and Touche LLP as the company’s independent registered public accounting firm for the current fiscal year.

3.Approval, on an advisory basis, of the compensation of the company’s named executive officers.

4.Transaction of such other business as may properly come before the meeting or any postponement or adjournment thereof.

Stockholders of record at the close of business on March 18, 2019April 14, 2022 will be entitled to notice of and to vote at the meeting or any postponement or adjournment thereof.

Los Angeles, California
April 5, 2019

WHETHER OR NOT YOU EXPECT TO ATTEND THE ANNUAL MEETING IN PERSON,ONLINE, IN ORDER TO ENSURE REPRESENTATION OF YOUR SHARES, PLEASE VOTE AS PROMPTLY AS POSSIBLE VIAPOSSIBLE. YOU ARE URGED TO SUBMIT YOUR PROXY OR VOTING INSTRUCTIONS ELECTRONICALLY OR BY TELEPHONE BY FOLLOWING THE INSTRUCTIONS ON YOUR NOTICE OF INTERNET OR TELEPHONE AS INSTRUCTED IN THESEAVAILABILITY OF PROXY MATERIALS OR, IN ANYIF YOU RECEIVED A PRINTED COPY OF THE PROXY MATERIALS, ON YOUR PROXY CARD OR VOTING INSTRUCTION FORM. IF YOU REQUESTED A PRINTED COPY OF YOUR PROXY MATERIALS, YOU MAY ALSO VOTE BY MAIL BY SIGNING, DATING, AND RETURNING YOUR PROXY CARD OR VOTING INSTRUCTION FORM YOU RECEIVED OR, IF THIS PROXY STATEMENT WAS MAILED TO YOU, BY COMPLETING, DATING AND SIGNING THE ENCLOSED PROXY CARD AND MAILING IT IN THE ENCLOSED ENVELOPE. NO POSTAGE NEED BE AFFIXED IFPRE-PAID ENVELOPE PROVIDED. VOTING NOW VIA PROXY WILL NOT LIMIT YOUR RIGHT TO CHANGE YOUR VOTE OR TO ATTEND THE PROXY CARD IS MAILED IN THE UNITED STATES.ANNUAL MEETING ONLINE.

​	By Order of the Board of Directors,
​
​	Aaron Saltz General Counsel and Corporate Secretary

New York, New York
April 26, 2022

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

Important Notice RegardingThis proxy statement contains forward-looking statements, including statements based upon or relating to our expectations, assumptions, estimates, and projections. In some cases, you can identify forward-looking statements by terms such as “may,” “might,” “will,” “objective,” “intend,” “should,” “could,” “can,” “would,” “expect,” “believe,” “design,” “anticipate,” “estimate,” “predict,” “potential,” “plan” or the Internet Availabilitynegative of Proxy Materialsthese terms, and similar expressions. Such forward-looking statements may include, but are not limited to, statements concerning acquisitions by the Company, including the acquisition of SpotX, Inc. (“SpotX,” and such acquisition the “SpotX Acquisition”), or SpringServe, LLC (“SpringServe” and such acquisition the “SpringServe Acquisition”), or the anticipated benefits thereof; statements concerning potential synergies from the Company’s acquisitions; statements concerning the potential impacts of the COVID-19 pandemic on our business operations, financial condition, and results of operations and on the world economy; our anticipated financial performance; anticipated benefits or effects related to our completed merger with Telaria, Inc. in April 2020 (“Telaria” and such merger the “Telaria Merger”); key strategic objectives, industry growth rates for ad-supported connected television (“CTV”) and the Stockholders Meetingshift in video consumption from linear TV to CTV; anticipated benefits of new offerings; the impact of transparency initiatives we may undertake; the impact of our traffic shaping technology on our business; the effects of our cost reduction initiatives; scope and duration of client relationships; the fees we may charge in the future; business mix; sales growth; benefits from supply path optimization; the development of identity solutions; client utilization of our offerings; our competitive differentiation; our market share and leadership position in the industry; market conditions, trends, and opportunities; certain statements regarding future operational performance measures; and other statements that are not historical facts. These statements are not guarantees of future performance; they reflect our current views with respect to future events and are based on assumptions and estimates and subject to known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be Held on May 15, 2019:materially different from expectations or results projected or implied by forward-looking statements.

The company’s 2019 Proxy StatementSuch risks and additional factors that could cause actual results to differ materially from those anticipated by our forward-looking statements include those described throughout our 2021 Annual Report foron Form 10-K and particularly under the fiscal year ended December 31, 2018heading “Risk Factors.” Unless required by federal securities laws, we assume no obligation to update any of these forward-looking statements, or to update the reasons actual results could differ materially from those anticipated, to reflect circumstances or events that occur after the statements are available at http://www.astproxyportal.com/ast/18899.made. Given these uncertainties, investors should not place undue reliance on these forward-looking statements.

Readers should carefully review this proxy statement and the documents that we have filed or will file with the SEC that disclose risks and uncertainties that may affect our business.

Magnite, Inc.
1250 Broadway, 15^th Floor
New York, New York 10001

The Rubicon Project, Inc.
12181 Bluff Creek Drive, 4th Floor
Los Angeles, California 90094

PROXY STATEMENT FOR THE ANNUAL MEETING OF STOCKHOLDERS
TO BE HELD ON MAY 15, 2019JUNE 7, 2022

This proxy statement is provided in connection with the solicitation of proxies by the board of directors (the “board of directors” or “board”) of The Rubicon Project,Magnite, Inc. (the “company” or “Rubicon Project”“Magnite”) for use at the Rubicon ProjectMagnite’s annual meeting of stockholders to be held on Tuesday, June 7, 2022 at the company’s principal executive offices, located at 12181 Bluff Creek Drive, 4th Floor, Los Angeles, California 90094, on Wednesday, May 15, 2019 at 12:2:00 noon localp.m. Eastern time, and at any postponement or adjournment thereof (the “Annual Meeting”). In light of the ongoing coronavirus (COVID-19) pandemic, and out of an abundance of caution and appreciation for our stockholders, the Annual Meeting will be a virtual meeting via live webcast on the Internet. You will be able to attend the Annual Meeting, view the list of our registered stockholders, vote and submit your questions during the meeting by visiting https://web.lumiagm.com/293659257 and entering the control number included in the Notice of Internet Availability or the proxy card or voting instruction form (if you received a printed copy of the proxy materials) that you receive. Beneficial owners should review the proxy materials and their voting instruction form or Notice of Internet Availability for information about how to vote in advance of and how to participate in the Annual Meeting. You will not be able to attend the annual meeting in person.

IMPORTANT NOTICE REGARDING INTERNET AVAILABILITY OF PROXY MATERIALS

This proxy statement and our Annual Report on Form 10-K for the year ended December 31, 2021 (the “2021 Annual Report”) are available on the Internet at www.proxyvote.com. These materials are also available on our corporate website at http://investor.magnite.com/. The other information on our corporate website does not constitute part of this proxy statement.

GENERAL INFORMATION ABOUT THE ANNUAL MEETING

You are invited to attend the Annual Meeting via live webcast, and we request that you vote on the proposals described in this proxy statement.statement as soon as possible. You can vote your shares without attending the Annual Meeting by appointing a proxy to vote your shares as explained below. Please note that if your shares are held of record by a broker, bank or other nominee, you should contact your bank, broker or other nominee (preferably at least several days before the Annual Meeting) and you decideobtain a “legal proxy” in order to be able to attend, andparticipate in, or vote at the Annual Meeting in person, your vote in person at theMeeting. See “Matters Relating to Virtual Annual Meeting will not be effective unless you present a legal proxy, issued in your name from your broker, bank or other nominee.Meeting” below for further instructions.

Notice of Internet Availability of Proxy Materials

In accordance with rules and regulations adopted by the Securities and Exchange Commission (the “SEC”), instead of mailing a printed copy of our proxy materials, we are furnishing proxy materials to our stockholders on the Internet and mailing printed copies of the proxy materials only to a limited number of our stockholders. If you are a stockholder of record and you have received a printed copy of these proxy materials by mail, you may simply complete, sign and return your proxy card by mail or follow the instructions on your proxy card to submit your proxy via the Internet or telephone. If you hold your shares in street name, which means your shares are held of record by a broker, bank, or other nominee, you will receive instructions from your broker, bank, or other nominee on how to vote your shares. Stockholders receiving a Notice of Internet Availability of Proxy Materials by mail will generally not receive a printed copy of the proxy materials unless they specifically request a printed copy in accordance with the instructions included in the Notice of Internet Availability of Proxy Materials. The Notice of Internet Availability of Proxy Materials provides instructions as to how to (i) access and review the information contained in the proxy materials, (ii) submit voting instructions via the Internet or telephone or by mail, and (iii) request a printed copy of the proxy materials. You may also participate in and vote at the Annual Meeting by visiting the following website: https://web.lumiagm.com/293659257. See “Matters Relating to Virtual Annual Meeting” below for further instructions. Even if you plan to participate in the Annual Meeting online, we recommend that you submit your proxy or voting instructions in advance to authorize the voting of your shares at the Annual Meeting so that your vote will be counted if you later are unable to attend the Annual Meeting online.

We intend to begin distributing our proxy materials to stockholders via paper copy mailing and the Notice of Internet Availability of Proxy Materials on or about April 5, 2019.26, 2022.

Business to be Conducted at Annual Meeting; Recommendation of Board of Directors

Each properly submitted proxy will be voted in accordance with the stockholder’s instructions contained therein. If no choice is specified, properly executed proxies that have not been revoked will be voted in accordance with the recommendations of the board of directors:directors as follows:

•FOR election of each of the Class II directors to serve until the company’s 2025 annual meeting of stockholders and until their respective successors are duly elected and qualified (see “Proposal 1 – Election of Directors”);

•FOR ratification of the selection of Deloitte and Touche LLP as the company’s independent registered public accounting firm for the current fiscal year (see “Proposal 2 – Ratification of the Selection of Deloitte and Touche LLP as Independent Registered Public Accounting Firm”); and

•FOR approval, on an advisory basis, of the compensation of the company’s named executive officers (see “Proposal 3 – Advisory Vote to Approve the Compensation of our Named Executive Officers”).

As to any other business that may properly come before the Annual Meeting, the persons acting as proxies will vote, or otherwise act, in accordance with their judgment on such matter. Our board of directors does not presently know of any other business that may come before the Annual Meeting.

2

The company will pay all costs of proxy solicitation. In addition to solicitations by mail, our directors, officers and employees, without additional remuneration, may solicit proxies by telephone, facsimile and personal interviews, and we reserve the right to retain outside agencies for the purpose of soliciting proxies. Brokers, custodians, and fiduciaries will be requested to forward proxy soliciting materials to the owners of stock held in their names and, as required by law, we will reimburse them for their out-of-pocket expenses in this regard.

Matters Relating to Virtual Annual Meeting

Our board of directors annually considers the appropriate format of our annual meeting of stockholders. As part of our effort to maintain a safe and healthy environment for our directors, members of management and stockholders who wish to attend the Annual Meeting, and in light of the COVID-19 pandemic, our board of directors believes that hosting a virtual Annual Meeting is in our best interest and the best interest of our stockholders and enables increased stockholder attendance and participation. Furthermore, our board of directors has determined that hosting a virtual annual meeting of stockholders will provide expanded access, improved communication, and cost savings. Hosting a virtual meeting enables increased stockholder attendance and participation since stockholders can participate from any location around the world. We intend that the virtual meeting format will provide stockholders a similar level of transparency to the traditional in-person meeting format and we take steps to ensure such an experience. Our stockholders will be afforded the same opportunities to participate at the virtual Annual Meeting as they would at an in-person annual meeting of stockholders.

The live audio webcast of the Annual Meeting will begin promptly at 2:00 p.m. Eastern time. Online access to the audio webcast will open 15 minutes prior to the start of the Annual Meeting to allow time for you to login and test your internet-connected device’s audio system. We encourage you to access the meeting in advance of the designated time. We will have technicians ready to assist you with any technical difficulties you may have accessing the virtual meeting or submitting questions. If you encounter any difficulties accessing the virtual meeting during the check-in or meeting time, please call the technical support number that will be posted on the virtual meeting log in page.

If you want to participate in and vote at the Annual Meeting, you will need will need the control number included on your Notice of Internet Availability of Proxy Materials or your proxy card or voting instruction form (if you received a printed copy of the proxy materials) or included in the email to you if you received the proxy materials by email in order to be able to vote your shares or submit questions during the Annual Meeting. 

In addition, if you hold your shares in “street name” through an intermediary, such as a bank, broker or other nominee, in order to participate in and vote at the Annual Meeting you must first obtain, in advance, fromyour bank, broker or other nominee, a legal proxy reflecting the number of shares of the Company’s common stock that you held as of the record date, your name and email address, unless you previously obtained a legal proxy from your bank, broker or other nominee. You must then submit a request for registration to AST by email to proxy@astfinancial.com. Requests for registration must be labeled as “Legal Proxy” and be received by AST no later than 5:00 p.m. Eastern Time on May 27, 2022. Obtaining a legal proxy may take several days, or longer, and stockholders are advised to register as far in advance as possible. Proxy holders registered with AST will receive a control number and may access the Annual Meeting as described in the paragraph above for stockholders of record.

Our virtual Annual Meeting allows stockholders to submit questions and comments before and during the Annual Meeting. Stockholders who have accessed the Annual Meeting with a control number may submit questions during the Annual Meeting that are pertinent to the Company and the items being brought before a vote at the Annual Meeting, as time permits and in accordance with our rules of procedure for the Annual Meeting. If you wish to submit a question, you may do so when you are logged into the virtual meeting platform with your control number by typing your question in the designated spot on the dashboard and clicking “Submit.” After the Annual Meeting, we will spend up to 15 minutes answering stockholder questions that comply with the rules of conduct for the Annual Meeting, which will be posted on the virtual meeting web portal. To the extent time doesn’t allow us to answer all of the appropriately submitted questions, we will answer them in writing on our investor relations website at http://investor.magnite.com/ soon after the meeting. If we receive substantially similar questions, we will group such questions together and provide a single response to avoid repetition.

Voting and Quorum Requirements

On March 18, 2019,April 14, 2022, the record date for the determination of stockholders entitled to notice of and to vote at the Annual Meeting, there were outstanding and entitled to vote an aggregate of 51,804,341132,194,776 shares of our common stock, constituting all of our voting stock. Holders of our common stock are entitled to one vote per share. The holders of a majority of the shares of our common stock outstanding on the record date and entitled to vote at the Annual Meeting, present in personvia live webcast or by proxy, will constitute a quorum for the transaction of business at the Annual Meeting and any adjournments and postponements thereof. Shares of our common stock represented in personvia live webcast or by proxy (including broker non-votes and shares that abstain or do not vote with respect to one or more of the matters presented for stockholder approval) will be counted for purposes of determining whether a quorum is present at the Annual Meeting.

You may vote FOR, AGAINST or ABSTAIN with respect to each director nominee (Proposal 1) and, ratification of the selection of Deloitte &and Touche LLP as our independent registered public accounting firm for the current fiscal year (Proposal 2), and approval of the compensation of the company’s named executive officers (Proposal 3).

Robert F. Spillane joined our board of directors in connection with our initial public offering in April 2014. From 1998 to 2017, Mr. Spillane was a Managing Principal at DigaComm, L.L.C., a private investment firm that leads early-stage venture capital transactions, primarily involving companies in technology and digital media. Mr. Spillane was formerly a Principal and President and CEO of the investment group DM Holdings, Inc., which was formed in 1991 to acquire Donnelley Marketing, Inc. from The Dun and Bradstreet Corporation. Donnelley Marketing was a leading direct marketing and information services company. Mr. Spillane served as President and CEO, and on the board of directors of Donnelley Marketing, Inc. Prior to joining DM Holdings, Mr. Spillane was the Executive Vice President of Diamandis Communications, Inc., then a leading consumer magazine publisher, formed in 1987 in a leveraged buyout of CBS Magazines from CBS Inc., and also served as a member of the Diamandis board of directors from 1987 to 1990. Prior to Diamandis, Mr. Spillane held various executive positions with CBS, Inc., including Senior Vice President Group Publisher, Vice President of Circulation, Vice President General Manager of the CBS Special Interest Magazine Group, and Vice President Sales and Marketing of Fawcett Books. His ten-year career at CBS culminated in service from 1985 to 1987 as Senior Vice President, Publishing of CBS Magazines. In that capacity, he was directly responsible for 10 magazines. From 1972 to 1977, Mr. Spillane held various positions with Chesebrough Ponds, Inc. Mr. Spillane also served on the board of directors of TVSM, Inc., a private media company, from1992-1998.from 1992-1998. Mr. Spillane brings to the board expertise in the publishing and advertising businesses, as well as significant experience with operations and mergers and acquisitions.

Incumbent Directors – Class I

Frank Addante is our founder and has been a member and Chairman of our board of directors since 2007 and served as our Chief Executive Officer from April 2007 to March 2017 and our Chief Product Architect from November 2014 to February 2016. From March 2017 to June 2018, he was employed by the company, reporting to and assisting the Chief Executive Officer, including by providing analysis and advice in the areas of strategy, innovation, and advertising technology market conditions and dynamics. In 2002, Mr. Addante founded the email infrastructure provider StrongMail Systems, Inc. From January 1998 to November 2000, Mr. Addante was CTO and Technology Founder of L90, an Internet advertising company, where he pioneered one of the Internet’s first ad serving platforms, adMonitor. Mr. Addante started his Internet career with the creation of Starting Point, a search engine. Mr. Addante brings to our board of directors thorough knowledge of our company and extensive experience in advertising automation and related systems engineering, innovation, and executive leadership.

Robert J. Frankenberg joined our board of directors in connection with our initial public offering in April 2014. Mr. Frankenberg has owned NetVentures, a management consulting and investment firm focused on the high-tech industry, since 1996. He served on the board of directors of public company Nuance Communications from March 2000 to June 2018. He previously served as a member of the boards of directors of public companies Polycom from October 2013 to September 2016, Wave Systems from December 2011 to June 2015 and National Semiconductor until October 2011. He also serves on the boards of private companies Veracity Networks, SQLStream, and Sylvan Source, as well as the Sundance Institute board.and Western Governor’s University (WGU) Development. Prior to its sale in 2004, Mr. Frankenberg chaired Kinzan, a leading provider of Internet services platforms. Mr. Frankenberg was the chairman, president, and CEO of Encanto Networks from June 1997 to July 2000 when the company’s major business was sold to Avaya. Encanto was a leading provider of eBusiness software and services to small business. From April 1994 to August 1996, Mr. Frankenberg was the Chairman/CEO of Novell, a networking software company. Prior to Novell, Mr. Frankenberg was the Vice President &and Group General Manager of Hewlett-Packard’s Personal Information Products Group, responsible for HP’s personal computer, server, networking, office software, calculator, and consumer product lines. Mr. Frankenberg joined Hewlett-Packard in 1969 as a manufacturing technician, later became a design engineer, software designer, project manager, engineering and marketing executive, and general manager. He became a corporate vice president in 1990 and general manager of the Personal Information Products Group in 1991. He served in the US Air Force from 1965 to 1969. Mr. Frankenberg previously served on various other boards, including for America OnLineOn Line (AOL), and holds several computer design patents. He brings to the board a deep knowledge of software, computer networks and systems, business operations, the technology industry, and public company governance and board service.

Sarah P. Harden joined our board of directors in July 2019. Ms. Harden brings more than two decades of experience in digital media, entertainment and direct-to-consumer video to the Company’s Board. Since January 2018, Ms. Harden has served as the Chief Executive Officer of Reese Witherspoon’s media company Hello Sunshine, which was acquired by Blackstone in August 2021. Prior to that, Ms. Harden held executive-level positions at Otter Media/The Chernin Group from 2013 to 2018, including President and Executive Vice President. Ms. Harden previously served as board member of privately held ESPN-Star Sports, Star China Media and The Moby Group and as a board director overseeing successful acquisitions and exits of private portfolio companies including Crunchyroll, Fullscreen, Roosterteeth, McBeard, and Stagebloc. Ms. Harden received her MBA from Harvard Business School and graduated with honors with a B.A. in international relations from The University of Melbourne. Ms. Harden brings to the board extensive experience leading and growing digital video, media and entertainment companies.

6

Incumbent Directors – Class III

Lewis W. ColemanJames Rossman has been a member of our board of directors since December 2015.April 2020. He is the retired Vicepreviously served as a member of Telaria’s board from January 2011 until April 2020, and served as Chairman of DreamWorks Animation,Telaria’s board from August 2012 to May 2013. Mr. Rossman currently serves as an Operating Partner at Silver Lake. From November 2012 to April 2018, he served as Special Advisor to General Atlantic, a position he held from July 2014global growth equity firm. From April 2009 to January 2015. Prior to that,June 2012, he served in various executive-level positions with DreamWorks since December 2005,roles at AKQA Inc., a digital services company, including President and Chief Operating Officer. From April 2001 to March 2009, Mr. Rossman served in several roles at Digitas, Inc., an integrated advertising agency and a member of the Publicis Groupe, S.A. (as of 2007), including as Chief Operating Officer. Mr. Rossman received a B.A. in economics from Trinity College and an M.M.M. from the Kellogg School of Management at Northwestern University. Mr. Rossman brings significant experience in operating and managing media agencies and advertising technology companies.

Diane Yu has been a member of our board of directors since March 2022. She served as the Chief Technology Officer of Better Holdco, Inc., which operates Better.com, an online platform for mortgage origination and related services, from January 2021 to April 2022, and she currently serves as an advisor to Better. Ms. Yu is the Co-Founder of FreeWheel Media, Inc., which provides a technology platform for the management and monetization of digital television advertising, and served as its Chief Technology Officer from 2007 to 2014, when FreeWheel was acquired by Comcast. Following the sale, Ms. Yu served as Chief Technology Officer of Comcast’s Advanced Advertising Division. Prior to co-founding FreeWheel, Ms. Yu spent over nine years at DoubleClick, where she served as the Vice President of engineering from 2005 until 2007. She received her Bachelor’s degree from Peking University in 1995 and a Master’s degree in Mathematics from the University of Ohio in 1998. Ms. Yu brings to the board extensive experience building, leading and scaling engineering teams for large digital advertising technology companies.

Incumbent Directors – Class III

Paul Cainehas been a member and Chairman of our board of directors since April 2020. Hepreviously served as the non-executive Chairman of Telaria from January 1, 2020 until April 2020 and as a member of Telaria’s board of directors from June 2014 until April 2020. He served as Telaria’s executive Chairman from July 2017 to December 2005 31, 2019 and Telaria’s Interim Chief Executive Officer from February 2017

to July 2017 and as the non-executive Chairman of the Board from July 2016 to February 2017. Mr. Caine has served as President, On Location at Endeavor Group Holdings, Inc. since January 2020. Mr. Caine has served as the Chairman and Executive Director of the Board of Engine Group, a global marketing company, since January 2018, and as CEO and Founder of PC Ventures, LLC, an investment and advisory firm since August 2017. Mr. Caine served as the Chief Global Revenue Officer for Bloomberg Media from June 2014 to July 2016. From April 2013 to January 2014 he served as Chief FinancialExecutive Officer and a member of the board of directors of WestwoodOne, Inc., the largest independent national audio media company in the U.S. From 1989 to 2013, Mr. Caine served in various capacities at Time Inc., including Executive Vice President, Chief Revenue Officer and Group President Time Inc. from January 2011 until April 2013, Executive Vice President, President and Group Publisher, Style and Entertainment Group from January 2010 to January 2011, and President, Style and Entertainment Group from January 2008 to January 2010. From 2007 to 2011, Mr. Caine served on the board of directors of Nexcen Brands, Inc., a strategic brand management company with a focus on retail franchising, where he served as a member of the audit and governance committees. Mr. Caine received a B.A. in Telecommunications with a minor in Business from Indiana University. Mr. Caine brings to the board expertise in branding and multi-media advertising sales and marketing, as well extensive experience serving on the boards of directors of public and private companies.

Doug Knopper has been a member of our board of directors since April 2020. He previously served as a member of Telaria’s board of directors from October 2018 until April 2020. Mr. Knopper is the Co-Founder of FreeWheel Media, Inc. and served as its Co-Chief Executive Officer from February 2007 to September 2015,2017. FreeWheel, which was acquired by Comcast in 2014, provides a technology platform for the management and acting Chief Accounting Officer from June to September 2014.monetization of digital television advertising. Prior to joining DreamWorks,founding FreeWheel, Mr. Coleman wasKnopper served as the PresidentChief Executive Officer of the GordonBitPass Inc. from 2005 to 2007 and Betty Moore Foundationas Senior Vice President/General Manager of DoubleClick Inc. from its founding in November 2000 to December 2004. Prior2005. Mr. Knopper received a B.A. from the University of Michigan and an M.B.A from Georgetown University. Mr. Knopper brings to that, Mr. Coleman wasthe board deep expertise and business relationships in digital video advertising and CTV, as well as experience founding, building and leading advertising technology companies.

David Pearson has been a Senior Managing Director at Montgomery Securities and then President and Chief Operating Officermember of its successor, Bancour board of America Securities, where he alsodirectors since March 2022. He has served as Chairman from 1998 to 2000. Before then, Mr. Coleman spent ten years at Bank of America where he served as Vice Chairman and Chief Financial Officer. He spent the previous 21 years at Wells Fargo Bank, where his positions included Chief Credit Officer and Chairman of the Credit Policy Committee, and at Bank of California. Mr. Coleman currently serves on the board of directors of Immune Design, a publicly traded clinical-stage immunotherapy company focused on oncology, as well as DCI, LLC, a private fund management company, and Vista Capital Advisors (formerly eBond Advisors)Lee Enterprises Inc., a private financial technology company. Mr. Coleman’s previouspublic media company listed on Nasdaq, since February 2020, and is also a member of Lee’s audit committee. He has also served on the board experience includes Chironof directors of Potbelly Corporation, Regal Entertainment, Bank of America, DreamWorks Animation and Northrop Grumman,a Nadaq listed company, since April 2022, where he sits on the audit committee. Mr. Pearson was Chief Financial Officer of Vonage Holdings Corp., a public cloud technology company, from May 2013 until August 2020. Before Mr. Pearson joined Vonage, he spent over nine years with Deutsche Bank Securities as a Managing Director and Global Media & Telecom Group Head. Prior to joining Deutsche Bank, Mr. Pearson served in various roles at Goldman, Sachs & Co. in the Lead Independent Director.Technology, Media & Telecommunications practice for over nine years, including as Managing Director from 2002 to 2003. Mr. ColemanPearson started his career at Coopers & Lybrand and holds a M.B.A. from Harvard Business School and an A.B. in Political Science and Organizational Behavior from Brown University. Mr. Pearson brings to the board an extensive backgroundexpertise in consumer mediacapital markets, mergers and technology,acquisitions and successful track record of expanding businesses into emerging markets,public company accounting, controls and financial reporting, as well as significant executive level andoperational experience as a public company board experience.executive.

Lisa L. Troe has been a member of our board of directors since February 2014. She iswas a Senior Managing Director and co-founder of Athena Advisors LLC, a businessan advisory firm a position she has held sinceco-founded to provide services in securities litigation, public company accounting, financial reporting and disclosure, and other business needs and strategies, from January 2014.2014 to June 2021. From October 2005 to Decemberthrough 2013, Ms. Troe was a Senior Managing Director in the forensic and litigation consulting practice at FTI Consulting, Inc., a global business advisory firm. From January 1995 to Octoberthrough 2005, Ms. Troe served on the staff of the Division of Enforcement of the SEC’sU.S. Securities and Exchange Commission’s Pacific regional office, including seven years as an enforcement branch chiefEnforcement Branch Chief and six years as regional chief enforcement accountant.the Regional Chief Enforcement Accountant. From 1980 through 1994, Ms. Troe serves as a director and audit committee chair of TheraCann International Benchmark Corporation. HerTroe’s career includesincluded accounting positions in public and private companies and with a Big Four public accounting firm. Ms. Troe serves on three other public company boards: (i) HireRight Holdings Corp., which provides employers with global background screening and other workforce solutions, since March 2021; (ii) Stem, Inc., a global leader in AI-driven energy storage services, since April 2021; and (iii) Expro Group Holdings N.V., an oilfield services company, since October 2021. She served as a director on private company boards in multiple industries and as an independent member of a public company board special committee. Ms. Troe is a credentialed National Association of Corporate Directors Governance Fellow and member of the National Association of Corporate Directors, a CPA, and member of the American Institute of CPAs. In 2017, Ms. Troe completed the National Association of Corporate Directors Cyber-Risk Oversight Program and receivedholds a CERT Certificatecertificate in Cybersecurity Oversight fromcybersecurity issued by the Software Engineering Institute of Carnegie Mellon University.University, and is a member and Board Leadership Fellow of the National Association of Corporate Directors. Ms. Troe brings to the board an extensive background in public company governance and oversight, enterprise risk and crisis management, and public company accounting, and financial reporting as well as aand disclosure. She has diverse experience with manya wide range of industries, allowing her to bring additional perspective to our board.

Vote Required and Recommendationfor Election of our Board of Directors

Our bylaws provide that, in an uncontested election, each director nominee must receive a majority of votes cast in order to be elected to our board of directors. A “majority of votes cast” means the number of shares voted FOR a director nominee exceeds the number of shares voted AGAINST that director nominee. Each of our director nominees currently serves on the board. If a nominee who currently serves as a director is not re-elected, Delaware law provides that the director would continue to serve on the board as a “holdover director.” Our Corporate Governance Guidelines provide that each incumbent director nominee who is not re-elected is expected to submit to the board his or her resignation from our board of directors and all committees thereof. The nominating &and governance committee, composed entirely of independent directors, will evaluate and make a recommendation to the board with respect to any submitted resignation and the board must decide whether to accept or reject the resignation, or to take other action, within 90 days following certification of the stockholder vote. No director may participate in the nominating &and governance committee or the board’s consideration of his or her own resignation.

THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” THE ELECTION OF EACH OF MICHAEL BARRETT, RACHEL LAM AND ROBERT SPILLANE AS CLASS II DIRECTORS.

PROPOSAL 2 — RATIFICATION OF THE SELECTION OF DELOITTE AND TOUCHE LLP
AS INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The audit committee of our board of directors has selected Deloitte and Touche LLP (“Deloitte”) as our independent registered public accounting firm for the year ending December 31, 2022, and has further directed that management submit the selection of Deloitte as our independent registered public accounting firm for ratification by the stockholders at the Annual Meeting. Deloitte has served as our independent registered public accounting firm since 2018. Although stockholder approval of the selection of Deloitte is not required by law, our board of directors believes it is advisable as a matter of good corporate governance to give stockholders an opportunity to ratify this selection. If this proposal is not ratified at the Annual Meeting, the audit committee may (but will not be required to) reconsider its selection of Deloitte. Even if the selection is ratified, the audit committee may in its discretion select a different independent registered public accounting firm at any time during the year if it determines that such a change would be appropriate.

Representatives of Deloitte are expected to be present at the Annual Meeting and will have the opportunity to make a statement if they desire to do so and will also be available to respond to appropriate questions from stockholders.

Independent Registered Public Accounting Firm Fees

The aggregate fees billed for audit and other services provided in the last two fiscal years by Deloitte are as follows:

(1)Audit Fees cover professional services rendered for the audit of our annual financial statements and review of financial statements included in our quarterly reports on Form 10-Q, and services normally provided by the accountant in connection with statutory and regulatory filings or engagements.

(2)Audit-Related Fees cover assurance and related services that are reasonably related to the performance of audit or review of our financial statements and not reported as Audit Fees.

(3)Tax Fees cover tax compliance, advice, and planning services and consist primarily of review of consolidated federal income tax returns and foreign tax issues.

(4)All Other Fees in 2020 are related to license fees for accounting research software and Merger and Acquisition support. All Other Fees in 2021 related to license fees for accounting research software.

Pre-Approval Policy and Procedures

The audit committee has adopted policies and procedures relating to the pre-approval of all audit and non-audit services that are to be provided by our independent registered public accounting firm. The audit committee will not approve non-audit services that the independent registered public accounting firm is not permitted to perform under the rules of the SEC and Public Company Accounting Oversight Board.

On an annual basis, the independent registered public accounting firm will propose to the audit committee an audit plan and engagement letter describing the services the auditor expects to provide and related fees. The final engagement letter and fees agreed by the company acting pursuant to the direction of the audit committee, and all of the services covered by the final engagement letter, will be considered pre-approved by the audit committee.

The audit committee or the Chair of the audit committee acting by delegated authority will approve, if necessary, any changes in terms, conditions and fees under the engagement letter resulting from changes in the audit scope, company structure or other matters.

The audit committee has delegated to the Chair of the audit committee the authority to approve on a case-by-case basis any audit or non-audit services, in amounts up to $200,000 (1) per engagement, (2) per additional category of services, or (3) in excess of pre-approved amounts for the specified service. The Chair then reports any services so approved to the audit committee at its next regularly scheduled meeting.

All services rendered for fiscal 2021 and fiscal 2020 were pre-approved by the audit committee in accordance with the audit committee’s pre-approval policies and procedures described above.

Vote Required for Ratification of the Selection of our Independent Registered Public Accounting Firm

Ratification of the selection of our independent registered public accounting firm requires the affirmative vote of a majority of the shares represented at the Annual Meeting, either in person or by proxy, and entitled to vote on the proposal. Abstentions will be considered as a vote “AGAINST” this proposal.

THE BOARD OF DIRECTORS RECOMMENDS THAT STOCKHOLDERS VOTE “FOR” THE RATIFICATION OF THE SELECTION OF DELOITTE AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM.

PROPOSAL 3 — ADVISORY VOTE TO APPROVE THE COMPENSATION OF OUR NAMED EXECUTIVE OFFICERS

Under the Dodd-Frank Wall Street Reform and Consumer Protection Act, or the Dodd-Frank Act, and Section 14A of the Exchange Act of 1934, as amended (the “Exchange Act”), the company’s stockholders are entitled to vote to approve, on an advisory basis, the compensation of the company’s named executive officers as disclosed in this proxy statement in accordance with SEC rules.

This vote is not intended to address any specific item of compensation, but rather the overall compensation of the company’s named executive officers and the philosophy, policies and practices described in this proxy statement. The compensation of the company’s named executive officers subject to the vote is disclosed in the executive compensation tables and the related narrative disclosure contained in this proxy statement.  As discussed in those disclosures, the company believes that its compensation policies and decisions are focused on motivating employees through performance-based variable compensation while ensuring that executives are strongly aligned with the creation of long-term value for stockholders.  Compensation of the company’s named executive officers is designed to enable the company to attract and retain talented and experienced executives to successfully lead the company in a competitive environment.

Accordingly, the board of directors is asking the stockholders to indicate their support for the compensation of the company’s named executive officers as described in this proxy statement by casting a non-binding advisory vote “FOR” the following resolution:

“RESOLVED, that the compensation paid to the Company’s named executive officers, as disclosed pursuant to Item 402 of Regulation S-K, including the compensation tables and narrative discussion, is hereby APPROVED.”

Because the vote is advisory, it is not binding on the board of directors or the company. Nevertheless, the views expressed by the stockholders, whether through this vote or otherwise, are important to management and the board of directors and, accordingly, the board of directors and the compensation committee intend to consider the results of this vote in making determinations in the future regarding executive compensation arrangements. The board of directors recommendshas adopted a policy of providing for annual advisory votes to approve executive compensation. Unless the board of directors modifies its policy on the frequency of holding such advisory votes, the next such advisory vote will occur in 2023.

Vote Required for Approval, on an Advisory Basis, of the Compensation of our Named Executive Officers

Approval, on an advisory basis, of the compensation of our named executive officers requires the affirmative vote of a majority of the shares represented at the Annual Meeting, either in person or by proxy, and entitled to vote on the proposal. Abstentions will have the effect of a vote FOR“AGAINST” this proposal.   

THE BOARD OF DIRECTORS RECOMMENDS THAT STOCKHOLDERS VOTE “FOR” THE APPROVAL, ON AN ADVISORY BASIS, OF THE COMPENSATION OF THE COMPANY’S NAMED EXECUTIVE OFFICERS.

CORPORATE GOVERNANCE

Corporate Governance Guidelines

Our board of directors has developed corporate governance practices to help it fulfill its responsibility to stockholders to oversee the electionwork of eachmanagement in the conduct of Messrs. Barrettour business and Spillane as Class IIto seek to serve the long-term interests of stockholders. The Company’s corporate governance practices are memorialized in our Corporate Governance Guidelines which direct our board’s actions with respect to, among other things, the composition and director qualifications of our board of directors, the composition of the standing committees of our board of directors, director orientation and continuing education, stockholder communications with our board of directors, succession planning and the annual performance evaluation of our board of directors. A current copy of our Corporate Governance Guidelines is available on our website at http://investor.magnite.com.

7

CORPORATE GOVERNANCE

Director Independence

Rubicon ProjectOur common stock is listed on the New YorkNasdaq Global Select Market of The Nasdaq Stock Exchange,Market LLC (“Nasdaq”), which requires that a majority of a listed company’s board of directors be independent. In addition, the rules of the New York Stock ExchangeNasdaq require that, subject to specified exceptions, each member of a listed company’s audit, compensation and nominating/corporate governance committees be independent. Under the rules of the New York Stock Exchange,Nasdaq, a director will only qualify as an “independent director” if, in the opinion of the board of directors, affirmatively determines that the director has no materialdoes not have a relationship that would interfere with the company (either directly or asexercise of independent judgment in carrying out the responsibilities of a partner, stockholder, or officer of an organization that has a relationship with the Company).

director.

Our board of directors has undertaken a review of the independence of each director and considered whether each director has any material relationships with us. As a result of this review, our board of directors has determined that Mr. Frankenberg, Ms. Harden, Mr. Knopper, Ms. Lam, Mr. Pearson, Mr. Rossman, Mr. Spillane, Ms. Troe, and Messrs. Coleman, Frankenberg, Mandal, and SpillaneMs. Yu are independent directors as defined under the applicablelisting requirements and rules of the New York Stock ExchangeNasdaq for purposes of service on the board.board of directors. Mr. Barrett is not considered independent because he currently serves as our Chief Executive Officer. Mr. Caine is not considered independent due to his previous service as Executive Chairman and Interim Chief Executive Officer of Telaria.  

In addition to qualifying as “independent” under the listing requirements and rules of Nasdaq, members of the board’s audit committee and compensation committee members must also satisfy additional, heightened independence standards under applicable SEC rules and regulations and Nasdaq listing requirements. Our board of directors has determined that each member of our audit committee and compensation committee satisfies these heightened independence standards.

Board Leadership Structure

Our Corporate Governance Guidelines provide that our board of directors will determine in its discretion from time to time whether the roles of Chairman and Chief Executive Officer should be combined or separated. With the appointment of Mr. Barrett as Chief Executive Officer in March 2017, our board of directors determined to separate these roles and retained Mr. Addante as non-executive Chairman. Because ourOur board believes that strong, independent board leadership is a critical aspect of effective corporate governance, and to promote open discussion among our non-management directors, our Corporate Governance Guidelines provide that, when the Chairman is a non-independent director, the independent directors will designate an independent director to act as Lead Director.

In April 2020, upon the completion of the Telaria Merger, Mr. Caine was appointed as Chairman of the board. The responsibilities of the Chairman include: (1) leading and presiding at board meetings; (2) assisting in establishing the agenda for each board meeting, with input from the Lead Director, as appropriate; (3) conferring regularly with CEO; (4) consulting with the CEO regarding board meeting schedules and agendas; (5) presiding at executive sessions of the Board, other than sessions consisting solely of independent directors; (6) consulting with committees of the board on matters within the scope of their responsibilities; (7) facilitating communications between directors and between directors and senior management; (8) providing feedback between the CEO and directors regarding strategic issues, board management, and potential conflicts; (9) working with appropriate committees of the board to ensure adequate CEO and senior management succession plans are in place; and (10) being available for consultation and communication with major stockholders upon request.

Because Mr. Caine is not deemed independent, Robert J. Frankenberg has been appointed and currently serves in the role of Lead Director. The responsibilities of the Lead Director include: (1) presiding at executive sessions of the board in place of the Chairman, as well as at meetings of the board at whichindependent directors; (2) if the Chairman is not present, presiding at board meetings and meetingsexecutive sessions of independent or non-management directors; (2) approving information sent to the board; (3) approvingproviding input to the CEO and Chairman with respect to the board agenda and schedule for board meetings at which the Lead Director will preside, as well as other board meetings if the Chief Executive Officer and Chairman are the same person;schedule; (4) serving as liaison between the independent directors and the Chairman and/or Chief Executive Officer on sensitive matters; (5) being available for consultation and communication with major stockholders upon request; and (6) calling executive sessionsmeetings of ourindependent directors; and (7) serving as designated director for reviewing stockholder communications.

Board Size and Composition

Our board and independent or non-management directors. The independentof directors have selected Robert J. Frankenberg to serve as Lead Director becauseconsists of his significant experience as both an executive officer and director and his familiarity with technology companies and public company governance and board operation.eleven members.

Board and Committee Meetings

In 2018,2021, our board of directors met seven16 times, the audit committee met seven7 times, the compensation committee met seven7 times, and the nominating &and governance committee met four8 times. The independent directors met in executive sessions without management in connection with four of the board meetings, five of the audit committee meetings, and three of the compensation committee meetings. During 2018,2021, each director attended at least 75% of the aggregate number of board meetings and meetings held by all committees on which the director then served withduring the exceptiontime in which he or she served on our board of Mr. Coleman, who attended five of the seven (71%) audit committee meetings, and Mr. Mandal, who attended five of the seven (71%) compensation committee meetings.directors.

Our Corporate Governance Guidelines call for us to schedule annual meetings of stockholders to coincide when possible with one of the four regular quarterly board meetings. Directors are expected to attend the annual stockholders’ meeting absent unusual circumstances. A copy of the Corporate Governance Guidelines is posted on the “Corporate Governance” section of our Investor Relations website at http://investor.rubiconproject.com. All of our then-serving directors attended the 20182021 annual meeting.

8

Director Candidate Nominating Procedures

The process followed by the nominating &and governance committee to identify and evaluate director candidates includes requests for recommendations (which may include through retained third-party search firms, as well as less formal methods such as personal contacts), committee meetings from time to time to evaluate biographical information and material relating to potential candidates, and interviews of candidates by board members. In identifying and evaluating director candidates and determining whether to nominate any particular candidate, the nominating &and governance committee considers the director candidates’ specific experience, qualifications, attributes and skills, together with the following general characteristics and qualifications, which are set forth in our Corporate Governance Guidelines:

•highest personal and professional ethics, integrity, and values;

10•independent, creative, and disciplined thought processes;

•practical wisdom and mature judgment;

While•broad training and experience at the nominating & governance committee does not have policy-making or strategic level;

•a formal policy regardingrecord of achievement and expertise that is useful to the company and complementary to the background and experience of other board members, so that a useful balance of members on the board can be achieved and maintained;

•willingness to devote the required amount of time to carrying out the duties and responsibilities of board membership;

•commitment to serve on the board over a period of several years to develop knowledge about the company;

•unless management directors, independence under relevant standards;

•diversity itof occupational and personal backgrounds among the members of the board; and

•knowledge of sustainability and Environmental, Sustainability and Governance (“ESG”) issues and the evolving role of the Board in ESG oversight.

Diversity of ethnicity, gender, sexual orientation, cultural background and professional experience is a factor that the nominating &and governance committee takes into account in identifying director nominees. The nominating &and governance committee believes that diversity is important because different points of view and varied board member backgrounds and practical experience can contribute to the quality of the board’s operations and decision-making, and assesses board diversity, among other things, in its periodic assessment of the composition, operation, and effectiveness of the board.

The nominating &and governance committee does not assign specific weights to particular criteria, but does believe that the backgrounds and qualifications of our directors, considered as a group, should provide a composite mix of experience, knowledge and abilities that will facilitate our board’s fulfillment of its responsibilities.

Stockholders may recommend individuals to the nominating &and governance committee for consideration as potential director candidates and inclusion in our proxy statement for the 20202023 annual meeting of stockholders by submitting their names, together with appropriate biographical information and background materials. Such information should be sent to the Nominating &and Governance Committee, c/o Corporate Secretary, The Rubicon Project,Magnite, Inc., 12181 Bluff Creek Drive, 4th1250 Broadway, 15^th Floor, Los Angeles, California 90094.New York, New York 10001. Assuming that appropriate biographical and background material has been provided on a timely basis, the nominating &and governance committee will evaluate stockholder-recommended candidates by following the same process, and applying the same criteria, as it follows for other candidates. If our board determines to nominate a stockholder-recommended candidate, then his or her name will be included in our proxy materials, including our proxy card, for the 20202023 annual meeting of stockholders.

Board Evaluation Process

Our board of directors and each of our standing committees conducts an annual self-evaluation to assess its performance. Each director participates in these evaluations and our Chairman or Lead DirectorGeneral Counsel and the Chair of the nominating & Governanceand governance committee then review and discuss the results with the full board. In addition, as part of the process of considering directors for re-election to the board, individual directors are annually informally evaluated by the nominating &and governance committee on the basis of their attendance at meetings and their preparedness, participation, candor and overall contribution to the board, as well as other criteria that the nominating &and governance committee deems appropriate.

Communicating with the Independent Directors

Stockholders and other interested parties who wish to communicate on any topic with our board, or with a specific director or directors, including the Lead DirectorChairman or the independent directors as a group, may address such communications to our Boardboard of Directorsdirectors c/o Corporate Secretary, The Rubicon Project,Magnite, Inc., 12181 Bluff Creek Drive, 4th1250 Broadway, 15^th Floor, Los Angeles, California 90094.

New York, New York 10001.

Our board of directors will give appropriate attention to written communications that are submitted by stockholders, and will respond if and as appropriate. The Lead Independent Director, or the Chair of the nominating & governance committee, with the assistance of our General Counsel and Chief Financial Officer, is primarily responsible for reviewing communications from stockholders and for providing copies or summaries to the other directors as considered appropriate. In accordance with the procedures outlined in Rubicon Project’sMagnite’s Corporate Governance Guidelines, communications (or summaries thereof) that relate to corporate governance, long-term corporate strategy, and other important substantive matters should be forwarded to the other directors, unless there

is a compelling reason not to forward such communications. In general, the director who reviews such communications may decline to forward communications that relate to ordinary business affairs or personal grievances, or are repetitive or duplicative, unless there is a compelling reason to forward such communications.

Board’s Role in Risk Oversight

Our board of directors exercises oversight of risk management consistent with its duty to direct the management of the business and affairs of the company. The audit committee, pursuant to its charter, is responsible for reviewing company practices with respect to risk assessment and risk management. The audit committee works directly with

11

members of senior management and the company’s internal audit staff to fulfill this responsibility and reports as appropriate to our board. Our board’s other committees also participate in risk oversight by considering risk aspects of matters within the scope of their responsibilities.

Oversight of risk is also effected by our board as a whole in various ways.

•The board reviews the structure and operation of various departments and functions of the company. In those reviews, the board discusses with management risks affecting those departments and functions and management’s approaches to mitigating those risks.

•The board reviews and approves each year’s operating plan and budget, and these reviews cover risks that could affect the plan and measures to cope with those risks.

•In its review and approval of our Annual Reports on Form 10-K, the board reviews and discusses with management the company’s business and related risks, including as described in the “Business,” “Risk Factors” and “Management’s Discussion and Analysis” sections of the document. The audit committee conducts a similar process quarterly in connection with the preparation of Quarterly Reports on Form 10-Q.

•When the board reviews particular transactions and initiatives that require board approval as a legal matter, or that otherwise merit board involvement, the board generally includes related risk analysis and mitigation plans among the matters addressed with management.

•The board or audit committee meet quarterly with our internal or external cybersecurity resources to review the efficacy of our cybersecurity risk initiatives and related policies and procedures.

The day-to-day identification and management of risk is the responsibility of the company’s management. As the market environment, industry practices, regulatory requirements, and the company’s business evolve, it is expected that management and our board will respond with appropriate adaptations to risk management and oversight.

Our board believes that the process it has established to administer the board’s risk oversight function would be effective under a variety of leadership frameworks and, therefore, does not have a material effect on our choice of the board’s leadership structure described above under “Board Leadership Structure.”

Risk Assessment in Compensation Programs

The compensation committee annually assesses our executive and broad-based compensation and benefits programs on an overall basis to determine whether the programs’ provisions and operations create undesired or unintentional material risk. This risk assessment process takes into account numerous compensation terms and practices that we maintain that aid in controlling risk, including the mix of cash, equity, and near- and long-term incentive programs, the use of multi-year vesting periods for equity awards, and a variety of performance criteria for incentive compensation, the claw-back provisions that apply to our annual incentive cash plan and equity plan, and the cap on the maximum cash incentive awards that can be earned in a given year regardless of company performance. This risk assessment process also includes a review of program policies and practices, program analysis to identify risk and risk controls, and determinations as to the sufficiency of risk identification and risk control, the balance of potential risk to potential reward, and the significance of the programs and their risks to company strategy. Although the compensation committee reviews all significant compensation programs, it focuses on those programs with variable payout, in particular assessing the ability of participants to directly affect payouts, and the controls on such situations.

Based on the foregoing, we believe that our compensation policies and practices do not create risks that are reasonably likely to have a material adverse effect on the company as a whole. We also believe that our incentive compensation programs do not encourage risk-taking beyond the organization’s ability to effectively identify and manage significant risks; are compatible with effective internal controls and our risk-management practices; and are adequately supported by the compensation committee’s oversight of our executive compensation programs.

Board’s Role in Oversight of Environmental, Social and Governance Matters

We believe that a sustainable business strategy that integrates environmental, social and governance (ESG) considerations is key to creating long-term value for our stockholders and other stakeholders. We have a long history of integrating ESG considerations into our mission, business strategy, and operations, and considering the impact we have on our communities. We are focused on addressing these issues, both risks and opportunities, through our corporate strategy. By operating our advertising platforms in a responsible manner, engaging and developing our diverse workforce, and reducing our environmental impact, we aim to provide more sustainable products and services that deliver long-term value for our clients, employees, communities, investors, and other stakeholders.

Since the Company’s last annual meeting of stockholders, we have taken several important steps to advance our ESG strategy, including:

•Conducting our first ESG Priority Assessment to identify the ESG issues that are most impactful to our long-term strategy and our stakeholders;

•Identifying Magnite’s initial ESG strategy that prioritizes Talent Engagement, Responsible Advertising & Data Governance, and Energy & Environmental Efficiency;

•Establishing an internal ESG Committee to lead the development and implementation of our ESG strategy and program; and

•Developing a roadmap to implement the strategy and identify near and long-term KPIs and goals.

ESG Leadership & Oversight

Both our Board of Directors and Executive Leadership Team are actively engaged in Magnite’s ESG strategy. The Board has embraced the responsibility for overseeing our ESG programs and has had robust discussions covering a variety of ESG issues throughout the past year.

In 2021, we formalized our internal ESG Committee. This committee consists of senior leaders across the organization representing key business areas, including people, legal, finance, marketing, product management, data operations, and others. The committee is responsible for developing and overseeing the implementation of Magnite’s ESG strategy and related programs, and for providing regular updates to the Executive Leadership Team and Board of Directors.

Process & Priorities

In 2021, we conducted our first ESG materiality assessment to identify the topics that are most impactful to our business. This process took into consideration the priorities of our key stakeholders and our long-term strategic objectives. Through this process, we identified three ESG priorities:

We believe that integrating relevant ESG considerations into our long-term business strategy is key to delivering on our commitments to our stakeholders. We will continue to engage with our investors and other stakeholders to understand their ESG priorities, and we welcome stockholder perspectives and feedback on our ESG strategy.

For more information about our ESG strategy and priorities, please visit our ESG website at https://www.magnite.com/esg/.

Human Capital Management

We recognize that our people are our greatest asset in creating a truly healthy business that delivers great results for employees, clients, stakeholders and the communities we touch. We firmly believe in a culture of transparency and trust, and aim to provide ample opportunity for all employees to ask questions, interface with leadership, and express their preferences. We strive to build a culture of excellence that is high-performing and results-oriented while emphasizing collaboration and innovation and promotes diversity, equity, and inclusion. Magnite’s core values of ‘See the big picture’, ‘Raise the bar’, ‘Empower others’, and ‘Own the results’ are guiding principles of the design and implementation of people-centric programs and initiatives across the organization.

As a global employer, we value the diversity of background and experiences that our employees contribute to our company. In recognition of this, in 2021 we further developed our Magnify Council, an employee-led council focused on evolving our talent engagement practices and ensuring we prioritize what matters most to employees. This includes driving opportunities for employee growth and development, enhancing diversity, equity and inclusion initiatives, and investing in our communities based upon employee input.

Examples of how we highlight our cultural values through employee initiatives include:

•We seek individuals who are committed to seeing the big picture and being catalysts of change

•We ask our employees to empower others, make a difference and ensure our company is an exciting place to work, not just a “job”

•We reward team and individual excellence and are committed to creating an exceptional workplace environment

•We solicit feedback from our employees in annual engagement surveys

•We believe in continual feedback on performance. Our employees set goals at a regular cadence throughout the year and managers provide achievement ratings

•We have a partnership in place with She Runs It, an organization dedicated to the support and advancement of women in all facets of marketing, media and tech, which includes complimentary memberships for all employees, and access to mentoring programs and ongoing programming

•We support community investment by matching employee donations to certified non-profits and track our impact via corporate donations, partnerships, and investments

•We report DE&I and CSR measures via a bi-annual Transparency Scorecard

•We analyze voluntary employee turnover to understand and address trends

•We give equity to our employees to promote alignment and ownership

•We have a zero tolerance policy for discrimination and harassment

Our employees, and the talent they bring to bear, are our most valuable resource. The global COVID-19 pandemic created unprecedented challenges for our business and our people. In response, we took a number of measures to protect the health and safety of our employees, including deploying a global employee assistance program and launching a digital platform with access to live wellness classes and discussions.

Board Diversity

We seek to have a board that represents diversity of ethnicity, gender, sexual orientation, cultural background and professional experience, and the nominating and governance committee takes these factors into account in identifying director nominees. The nominating and governance committee believes that diversity is important because different points of view and varied board member backgrounds and practical experience can contribute to the quality of the board’s operations and decision-making, and assesses board diversity, among other things, in its periodic assessment of the composition, operation, and effectiveness of the board.

Code of Business Conduct and Ethics

Our board of directors has adopted a Code of Business Conduct and Ethics that applies to each of our directors, officers and employees. The full text of our Code of Business Conduct and Ethics is posted on the “Corporate Governance” section of our Investor Relations website at http://investor.rubiconproject.cominvestor.magnite.com. We intend to post any amendment to our Code of Business Conduct and Ethics, and any waivers of the Code for directors and executive officers, on the same website to the extent required by applicable law.rules adopted by the SEC and Nasdaq.

Policy Against Hedging and Pledging

We recognize that hedging against losses in company shares may disturb the alignment between stockholders and employees that our equity awards are intended to build. Accordingly, we have incorporated prohibitions on various hedging activities within our Insider Trading Policy, which applies to directors, officers and othercertain employees who we have designated as insiders.insiders, as well as such persons’ family members, life partners, or owned or controlled entities. The policy prohibits all transactions that are designed to hedge or offset any decrease in the market value of our securities, including prepaid variable forward contracts, equity swaps, futures, collars, exchange funds, options, puts and callscalls. The policy also prohibits pledging shares of our common stock as security as well as short sales and purchases or sales of puts or calls for speculative purposes.

Compensation Committee Interlocks and Insider Participation

Ms. Harden and Messrs. Coleman,Knopper, Rossman, and Frankenberg Mandal, and Spillane served on ourthe company’s compensation committee during the last completed fiscal year. None of the members of ourthe compensation committee is or has at any time been an officer or employee of Rubicon Project.the company. There are no interlocking relationships (and there were no such interlocking relationships during 2018)2021) between our board of directors, executive officers or ourthe compensation committee, on the one hand, and the board of directors, executive officers or the compensation committee of any other company.company, on the other hand.

12

DIRECTOR COMPENSATION

Each member of our board of directors who is not employed by us or any of our subsidiaries, referred to as a non-employee director, is compensated for service on our board through a combination of annual cash retainers and equity awards. For purposes of our director compensation program, a non-employee director is a member of theour board who is not, and has not been within the previous 180 days, either an employee of the companyours or any of itsour subsidiaries or a consultant performing material services to the companyus or any of itsour subsidiaries. In order to align the interests of non-employee directors and stockholders, equity awards constitute a majority of total director compensation.

Directors are reimbursed for travel, food, lodging and other expenses directly related to their activities as directors, such as attendance at board or committee meetings. Directors are also entitled to the protection provided by their indemnification agreements and the indemnification provisions in our certificate of incorporation and bylaws, and they receive coverage under a director and officer insurance policy that we maintain.

2021 Annual Cash Fees

Our non-employeeFor 2021, directors receivereceived annual cash retainer fees as described in the table below for board and committee service. The fees are paid in four equal quarterly advance installments and prorated for any partial year of board service.

2021 Market Assessment and 2022 Annual Cash Fees

Equity Awards

PriorIn late 2021, the compensation committee engaged Semler Brossy to changes to ourperform a comprehensive review of non-employee director compensation programpay to ensure the programs were competitive and reflective of the larger size of the company going forward. On November 18, 2021, our board of directors approved byrevised annual cash retainer fees, commencing January 1, 2022 as described in the table below for board and committee service

For 2022, directors will receive the following annual cash retainer fees for board and committee service. The fees are paid in October 2018 that is effectivefour equal quarterly advance installments and prorated for 2019 compensation,any partial year of board service.

Equity Awards

In 2021, equity compensation for non-employee directors consisted of (i) an initial equity award with a calculated value of $450,000$375,000 for each newly-elected or appointed non-employee director, and (ii) annual awards with a calculated value of $225,000. In October 2018,$125,000. On November 18, 2021, our board approved an increase in the board reducedvalue of annual awards to $170,000, commencing with the initial award to haveannual equity awards granted in 2022. For 2021, equity awards for directors consisted solely of restricted stock units (“RSUs”) covering a number of shares determined by dividing the calculated value of $375,000 and the annual award to a valueby the 20-day trailing average of $125,000 to bring the compensation back to medial levels in connection with making changes toCompany’s stock price on the equity mix to eliminate the stock option component and remove the price floor, as further described below.

grant date.

The initial equity award is granted on the date of appointment to the Boardboard or attainment of non-employee director status, unless the board or compensation committee specifyspecified another issuance date. Annual equity awards are issued on the date of each annual meeting or the date of attainment of non-employee director status. If no intervening annual meeting has been held, annual equity awards will be granted on a date specified by the compensation committee that is at least 30 calendar days after the first anniversary of the prior year’s annual meeting. The first annual award for non-employee directors who join the board at any time other than the date of an annual meeting is subject to proration for the partial year of service ending on the date of the next annual meeting.

Prior to the October 2018 amendments, each equity award consisted of stock options for a number of shares determined by dividing half of the calculated value of the award by the fair value of a single option on the grant date as determined for financial accounting purposes, and restricted stock units covering a number of shares determined by dividing half of the calculated value of the award by the closing price of a share of our common stock on the grant date. Stock options were granted with a per share exercise price equal to the closing price of a share of our common stock on the grant date. Notwithstanding the foregoing, if the closing price of our common stock was less than $12.00 on the grant date, then for stock options, $12.00 was used as the fair value of one share of common stock in the Black Scholes calculation used to determine the number of stock options to be granted,

13

Initial equity awards vest, subject to continued board service, in three equal annual increments, on the first, second, and third anniversaries of the date of commencement of board service or attainment of non-employee director status or, if earlier, upon (but effective immediately prior to) the occurrence of a change in control of the company.Magnite. Annual equity awards vest, subject to continued board service, on the first anniversary of the date of grant (or, if no intervening annual meeting has been held, annual equity awards will vest on the second anniversary of the prior year’s annual meeting) or, if earlier, upon the occurrence of either (1) a change in control of the companyMagnite (effective immediately prior thereto) or (2) the first regular annual meeting occurring in the year immediately following the year in which such annual equity awards were granted. In addition, if a non-employee director ceases board service for any reason other than removal for cause before vesting in full of equity awards, then the director’s awards vest with respect to a pro-rata portion of the underlying shares (up to but not exceeding the number of unvested shares remaining subject to such awards) determined based upon the period of board service. Vesting of equity awards will cease, and unvested equity awards will lapse, upon a recipient’s removal for cause from board service.

Director Equity Retention Guidelines

Under our equity retention guidelines implemented by the board in April 2016, each director is required to accumulate within five years from the later of the date the guidelines were implemented and the date of commencement of service for a new director, and thereafter to retain for the duration of board service, an amount of equity equal to five times the director’s base board cash compensation. Equity that counts toward the ownership requirement includes: (1) shares owned outright by the director or beneficially owned by the director by virtue of being held by a member of the director’s immediate family members residing in the same household or in a trust for the benefit of the director or his or her immediate family residing in the same household; (2) shares held in qualified plans or IRAs; (3) vested shares (or vested restricted stock units) deemed to be held in non-qualified plans; (4) the in-the-money portion of vested stock options (but not unvested stock options); and (5) unvested time-based restricted shares (or restricted stock units). Until the minimum level of company equity is achieved, a director is prohibited from selling or otherwise transferring beneficial ownership of more than one-half of: (a) the vested after-tax shares of our common stock obtained as a result of the vesting of any restricted stock or restricted stock unit award made after implementation of the equity retention guidelines; or (b) the shares of our common stock subject to the vested portion of any stock option award made after implementation of the equity retention guidelines, net of any shares surrendered or sold to cover exercise price and/or income tax resulting from the exercise.

20182021 Director Compensation Table

The following table sets forth all compensation provided to our non-employee directors for 2018.2021. The compensation for Mr. Barrett, our President and Chief Executive Officer, is described in the “Executive Compensation” section below. Mr. Barrett did not receive any compensation for his services as a director in 2018.2021.

(1)Consists of annual board retainer and fees for service as Chairman, a committee chair, committee member, or Lead Independent Director, as the case may be. See the narrative disclosure above for a description of such fees.

(2)In accordance with the rules of the SEC, these amounts represent the aggregate grant date fair value of the stock awards and option awards granted to the non-employee directors during the fiscal year computed in accordance with ASC 718. Our equity awards valuation approach and related underlying assumptions for awards granted in 2021 are described in Note 2 “Organization and Summary of Significant Accounting Policies—Stock-Based Compensation” and Note 13 “Stock-Based Compensation” to the Consolidated Financial Statements in our Annual Report on Form 10-K. The reported amounts do not necessarily reflect the value that may be realized by the non-employee director with respect to the awards, which will depend on future changes in stock value and may be more or less than the amount shown. The number of shares granted to directors was determined by dividing the approved value of the award ($125,000) by the 20-day trailing average of the Company’s stock price on the grant date, and accordingly the grant date fair value of the stock awards may differ from the value of the approved award.

(3)Stock awards for 2021 consisted of an annual award of 3,936 restricted stock units granted on June 28, 2021 to each director serving on our board at such time. As of December 31, 2021, the aggregate number of shares of our common stock covered by unvested stock awards held by each of our non-employee directors was as follows:

(4)As of December 31, 2021, the aggregate number of shares of our common stock covered by stock options held by each of our non-employee directors was as follows: