ALTAIR ENGINEERING INC.

1820 East Big Beaver Road

Troy, Michigan 48083

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To be held on May 20, 202116, 2024

To the Stockholders of

Altair Engineering Inc.

You are cordially invited to attend the Annual Meeting of Stockholders (the “Annual Meeting”) of Altair Engineering Inc. (the “Company”) to be held on Thursday, May 20, 202116, 2024 at 1:00 p.m. Eastern Time. In light of the coronavirus and governmental decrees that in-person gatherings be limited, and in the best interests of public health and the health and safety of our stockholders, employees and Board of Directors, weWe are planning to hold the Annual Meeting virtually via the Internet at www.virtualshareholdermeeting.com/ALTR2021.ALTR2024. You will not be able to attend the Annual Meeting at a physical location. At the Annual Meeting, stockholders will act on the following matters:

Only stockholders of record at the close of business on March 25, 202121, 2024 are entitled to receive notice of and to vote at the Annual Meeting or any postponement or adjournment thereof.

Your vote is important. Whether or not you plan to attend the meeting, please vote electronically via the Internet or by telephone, or, if you requested paper copies of the proxy materials, please complete, sign, date and return the accompanying proxy card or voting instruction card in the enclosed postage-paid envelope. If you attend the meeting and prefer to vote in person, you may do so even if you have already voted your shares. You may revoke your proxy in the manner described in the proxy statement at any time before it has been voted at the meeting.

By Order of the Board of Directors

/s/ James R. Scapa

James R. Scapa

Chairman and Chief Executive Officer

April 9, 20215, 2024

Troy, Michigan

TABLE OF CONTENTS

ALTAIR ENGINEERING INC.

PROXY STATEMENT

FOR THE 20212024 ANNUAL MEETING OF STOCKHOLDERS

GENERAL INFORMATION

This proxy statement contains information related to the Annual Meeting of Stockholders to be held on Thursday, May 21, 202116, 2024 at 1:00 p.m. Eastern Time. In light of the coronavirus and governmental decrees that in-person gatherings be limited, and in the best interests of public health and the health and safety of our stockholders, employees and Board of Directors, weWe are planning to hold the Annual Meeting virtually via the Internet, or at such other time and place to which the Annual Meeting may be adjourned or postponed. In order to attend our Annual Meeting, you must log in to www.virtualshareholdermeeting.com/ALTR2021ALTR2024 using the 16-digit control number on the Notice, proxy card or voting instruction form that accompanied the proxy materials. A list of record holders of our common stock entitled to vote at the Annual Meeting will be available for examination by any stockholder, for any purpose germane to the Annual Meeting, during the Annual Meeting on a reasonably accessible electronic network, and the information required to access such list will be provided with the notice of the meeting.

Proxies for the Annual Meeting are being solicited by Altair’s Board of Directors (the “Board”). This proxy statement is first being made available to stockholders on or about April 9, 2021.5, 2024.

Important Notice of Availability ofRegarding the Proxy Materials for the Annual Meeting of Stockholders to be held on May 21, 2021.16, 2024.

Our proxy materials including our Notice of Internet Availability of Proxy Materials, Proxy Statement for the 20212024 Annual Meeting, our annual report for the fiscal year ended December 31, 20202023 and proxy card are available on the Internet at www.proxyvote.com.Under Securities and Exchange Commission rules, we are providing access to our proxy materials by notifying you of the availability of our proxy materials on the Internet.

In this Proxy Statement, the terms “Altair,” “we,” “us,” and “our” refer to Altair Engineering Inc. The mailing address of our principal executive offices is Altair Engineering Inc., 1820 East Big Beaver Road, Troy, Michigan 48083.

About the Meeting

Why are we calling this Annual Meeting?

We are calling the Annual Meeting to seek the approval of our stockholders:

What are the Board’s recommendations?

Our Board believes that the election of the director nomineenominees identified herein the approval of the Altair Engineering Inc. 2021 Employee Stock Purchase Plan and the appointment of Ernst & Young LLP as our independent registered public accounting firm for the year ending December 31, 20212024 are advisable and in the

the resolution to approve that compensation. If you are a stockholder of record and you return a properly executed proxy card or vote by proxy over the Internet but do not mark the boxes showing how you wish to vote, your shares will be voted in accordance with the recommendations of the Board, as set forth above. With respect to any other matter that properly comes before our Annual Meeting, the proxy holders will vote as recommended by the Board or, if no recommendation is given, at their own discretion.

Who is entitled to vote at the meeting?

Only holders of record of our Class A common stock and Class B common stock at the close of business on the record date, March 25, 2021,21, 2024, are entitled to receive notice of the Annual Meeting and to vote either class of our common stock that they held on that date at the meeting, or any postponement or adjournment of the meeting. Each share of Class A common stock is entitled to one vote on each proposal and each share of Class B common stock is entitled to ten votes on each proposal.

As of the record date, there were 45,422,38056,945,384 shares of our Class A common stock outstanding and 29,600,19226,084,574 shares of our Class B common stock outstanding. Our Class A common stock and Class B common stock will vote as a single class on all matters described in this proxy statement. Our Class A common stock and Class B common stock are collectively referred to in this proxy statement as our common stock.

Who can attend the meeting?

All stockholders as of the record date, or their duly appointed proxies, may attend the Annual Meeting. Attendance at the Annual Meeting shall solely be via the Internet at www.virtualshareholdermeeting.com/ALTR2021ALTR2024 using the 16-digit control number on the Notice, proxy card or voting instruction form that accompanied the proxy materials. Stockholders will not be able to attend the Annual Meeting at a physical location.

The live webcast of the Annual Meeting will begin promptly at 1:00 pmp.m. Eastern Time. Online access to the audio webcast will open approximately 30 minutes prior to the start of the Annual Meeting to allow time for our stockholders to log in and test their devices’ audio system. We encourage our stockholders to access the meeting in advance of the designated start time.

An online portal will be available to our stockholders at www.proxyvote.com commencing approximately on or about April 9, 2021.5, 2024. By accessing this portal, stockholders will be able to vote in advance of the Annual Meeting. Stockholders may also vote, and submit questions, during the Annual Meeting on www.virtualshareholdermeeting.com/ALTR2021.ALTR2024. To demonstrate proof of stock ownership, you will need to enter the 16-digit control number received with your Notice, proxy card or voting instruction form to submit questions and vote at our Annual Meeting. If you hold your shares in “street name” (that is, through a broker or other nominee), you will need authorization from your broker or nominee in order to vote. We intend to answer questions submitted during the meeting that are pertinent to the Company and the items being brought for stockholder vote at the Annual Meeting, as time permits, and in accordance with the Rules of Conduct for the Annual Meeting. To promote fairness, efficiently use the Company’s resources and ensure all stockholder questions are able to be addressed, we will respond to no more than three questions from a single stockholder. We have retained Broadridge Financial Solutions to host our virtual annual meeting and to distribute, receive, count and tabulate proxies.

How do I vote?

Your vote is important. Instead of mailing a printed copy of our proxy materials to all of our stockholders, we provide access to these materials via the Internet. This reduces the amount of paper necessary to produce these materials as well as the costs associated with mailing these materials to all stockholders. Accordingly, on or about April 9, 2021,5, 2024, we will begin mailing a Notice of Internet Availability of Proxy Materials (the “Notice”) to all stockholders of record on our books at the close of business on the record date and will post our proxy materials at www.proxyvote.com. Stockholders may choose to access our proxy materials at www.proxyvote.com or may request to receive a printed set of our proxy materials. In addition, the Notice and that website provide information regarding how you may request to receive proxy materials in printed form by mail, or electronically by email, on an ongoing basis.

You may vote on the Internet, by telephone, by mail or by attending the Annual Meeting and voting electronically, all as described below. The Internet and telephone voting procedures are designed to authenticate stockholders by use of a control number and to allow you to confirm that your instructions have been properly recorded. If you vote by telephone or on the Internet, you do not need to return your proxy card or voting instruction card.

Vote on the Internet

If you are a stockholder of record, you may submit your proxy by going to www.proxyvote.com and following the instructions provided in the Notice. If you requested printed proxy materials, you may follow the instructions provided with your proxy materials and on your proxy card. If your shares are held with a broker, you will need to go to the website provided on your Notice or voting instruction card. Have your Notice, proxy card or voting instruction card in hand when you access the voting website. On the Internet voting site, you can confirm that your instructions have been properly recorded. If you vote on the Internet, you can also request electronic delivery of future proxy materials. Internet voting facilities are available nowfrom April 5, 2024 and will be available 24 hours a day until 11:59 p.m., Eastern Time, on May 19, 2021. 15, 2024.

Vote by Telephone

If you are a stockholder of record, you can also vote by telephone by dialing 1-800-690-6903. If your shares are held with a broker, you can vote by telephone by dialing the number specified on your voting instruction card. Have your proxy card or voting instruction card in hand when you call. Telephone voting facilities are available nowfrom April 5, 2024 and will be available 24 hours a day until 11:59 p.m., Eastern Time, on May 19, 2021. 15, 2024.

Vote by Mail

If you have requested printed proxy materials, you may choose to vote by mail, by marking your proxy card or voting instruction card, dating and signing it, and returning it in the postage-paid envelope provided. If the envelope is missing and you are a stockholder of record, please mail your completed proxy card to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. If the envelope is missing and your shares are held with a broker, please mail your completed voting instruction card to the address specified therein. Please allow sufficient time for mailing if you decide to vote by mail as it must be received by 11:5912:00 p.m., Eastern Time, on May 19, 2021.16, 2024.

You will have the right to vote on the day of, or during, the Annual Meeting on www.virtualshareholdermeeting.com/ALTR2021.ALTR2024. To demonstrate proof of stock ownership, you will need to enter the 16-digit control number received with your Notice, proxy card or voting instruction form to vote at our Annual Meeting.

Even if you plan to attend our Annual Meeting remotely, we recommend that you also submit your proxy as described above so that your vote will be counted if you later decide not to attend our Annual Meeting.

The shares voted electronically, telephonically, or represented by the proxy cards received, properly marked, dated, signed and not revoked, will be voted at the Annual Meeting.

What if I vote and then change my mind?

You may revoke your proxy at any time before it is exercised by:

Your latest vote will be the vote that is counted.

What is the difference between holding shares as a stockholder of record and as a beneficial owner?

Many of our stockholders hold their shares through a stockbroker, bank or other nominee rather than directly in their own name. As summarized below, there are some distinctions between shares held of record and those owned beneficially.

Stockholder of Record

If your shares are registered directly in your name with our transfer agent, American Stock Transfer & Trust Company, you are considered, with respect to those shares, the stockholder of record. As the stockholder of record, you have the right to grant your voting proxy directly to us or to vote at the Annual Meeting.

Beneficial Owner

If your shares are held in a stock brokerage account or by a bank or other nominee, you are considered the beneficial owner of shares held in street name, and these proxy materials are being forwarded to you by your broker, bank or nominee which is considered, with respect to those shares, the stockholder of record. As the beneficial owner, you have the right to direct your broker as to how to vote and are also invited to attend the Annual Meeting. However, because you are not the stockholder of record, you may not vote these shares unless you obtain a signed proxy from the record holder giving you the right to vote the shares. If you do not vote your shares or otherwise provide the stockholder of record with voting instructions, your shares may constitute broker non-votes. The effect of broker non-votes is more specifically described in “What“What vote is required to approve each proposal?proposal?” below.

With respect to the first proposal (election of a Class I director)directors), the directordirectors will be elected by a plurality of the voting power of the shares of our common stock present or represented by proxy and entitled to vote, and the director nomineenominees who receivesreceive the greatest number of votes at the Annual Meeting will be elected. As a result, abstentions and “broker non-votes” (see below), if any, will not affect the outcome of the vote on the first proposal.

With respect to the second and third and fourth proposals, to approve the Altair Engineering Inc. 2021 Employee Stock Purchase Plan, to cast an advisory vote on executive compensation and to ratify the appointment of Ernst & Young LLP, respectively, and the approval of any other matter that may properly come before the Annual Meeting, the affirmative vote of a majority of the voting power of the shares of our common stock present or represented by proxy and entitled to vote, is required to approve these proposals. As a result, abstentions will have the same practical effect as a negative vote on these proposals, and “broker non-votes” (see below), if any, will not affect the outcome of the vote on these proposals.

Holders of the common stock will not have any dissenters’ rights of appraisal in connection with any of the matters to be voted on at the meeting.

What are “broker non-votes”?

Banks and brokers acting as nominees are permitted to use discretionary voting authority to vote proxies for proposals that are deemed “routine” by the New York Stock Exchange, but are not permitted to use discretionary voting authority to vote proxies for proposals that are deemed “non-routine” by the New York Stock Exchange. The determination of which proposals are deemed “routine” versus “non-routine” may not be made by the New York Stock Exchange until after the date on which this proxy statement has been mailed to you. As such, it is important that you provide voting instructions to your bank, broker or other nominee, if you wish to determine the voting of your shares. If the New York Stock Exchange determines a proposal to be “non-routine,” failure to vote, or to instruct your broker how to vote any shares held for you in your broker’s names, will have the same effect as a vote against such proposal.

A broker “non-vote” occurs when a proposal is deemed “non-routine” and a nominee holding shares for a beneficial owner does not have discretionary voting authority with respect to the matter being considered and has not received instructions from the beneficial owner.

The election of a directordirectors (Proposal No. 1), the approval of the Altair Engineering Inc. 2021 Employee Stock Purchase Plan (Proposal No. 2) and the advisory vote on executive compensation (Proposal No. 3)2) are generally not considered to be a “routine” matter and brokers are not permitted to vote on these matters if the broker has not received instructions from the beneficial owner. Accordingly, it is particularly important that beneficial owners instruct their brokers how they wish to vote their shares. The ratification of our independent registered public accounting firm (Proposal No. 4)3) is generally considered to be a “routine” matter, and hence your brokerage firm may be able to vote on Proposal No. 43 even if it does not receive instructions from you, so long as it holds your shares in its name.

How are we soliciting this proxy?

We are soliciting this proxy on behalf of our Board and will pay all expenses associated therewith. Some of our officers and other employees also may, but without compensation other than their regular compensation, solicit proxies by mail or personal conversations, or by telephone, facsimile or other electronic means.

PROPOSAL 1: TO ELECT ONE DIRECTOR,TWO DIRECTORS, AS A CLASS I DIRECTOR,DIRECTORS, TO SERVE A THREE-YEARTHREE-

YEAR TERM EXPIRING AT THE ANNUAL MEETING IN 20242027 AND UNTIL HER SUCCESSOR HASTHEIR SUCCESSORS

HAVE BEEN DULY ELECTED AND QUALIFIED

Our Board is divided into three classes: Class I, Class II and Class III, with each class serving a three-year term. Vacancies on the Board may be filled only by persons elected by a majority of the remaining directors. A director elected by the Board to fill a vacancy in a class, including vacancies created by an increase in the number of directors, shall serve for the remainder of the full term of that class and until the director’s successor is duly elected and qualified.

Our Board presently has seven members. There are threetwo directors in the class (Class I) whose term of office expires in 2021 – Dr. Mary Boyce, Brett Chouinard and Jan Kowal. Messrs. Chouinard and Kowal are not standing for reelection at the Annual Meeting. As a result, the size2024. Each of the Board will be reduced to five members immediately prior to the Annual Meeting. Dr. Mary Boycethese directors has been nominated for reelectionelection as a Class I directordirectors at thethis Annual Meeting.

Dr. Boyce Each of the nominees listed below is currently a director of Altair. If elected at the Annual Meeting, Dr. Boycethe Class I nominees would serve until the 20242027 annual meeting and until his or her successor has been duly elected and qualified, or, if sooner, until herthe director’s death, resignation or removal.

Directors are elected by a plurality of the votes of the holders of shares present in person or represented by proxy and entitled to vote on the election of directors. Stockholders may not vote, or submit a proxy, for a greater number of nominees than the one nomineetwo nominees named below. The nomineenominees receiving the highest number of affirmative votes will be elected. Unless otherwise directed, shares represented by executed proxies will be voted for the election of the nomineenominees named below. If theany director nominee becomes unavailable for election as a result of an unexpected occurrence, shares that would have been voted for that nominee will instead be voted for the election of a substitute nominee proposed by our Board. Dr. BoyceEach person nominated for election has agreed to serve if elected. Our management has no reason to believe that Dr. Boyceany nominee will be unable to serve.

Class I NomineeNominees for Election for a Term Expiring at the 20242027 Annual Meeting

The following table sets forth the name, age, position and tenure of our Class I directordirectors who isare up for re-electionelection at the 20212024 Annual Meeting for a term expiring at the 2024Annual2027 Annual Meeting:

The following biographical descriptions set forth certain information with respect to Dr. Boyce,the director nominees, based on information furnished to Altair by sucheach director nominee.

Dr. Mary Boyce has served as a member of our board of directorsBoard since April 2018. Dr. Boyce is the chair of our technology committee, a role she has held since October 2018, and a member of our nominating and corporate governance committee, a role she has held since August 2018. Dr. Boyce is Professor of Mechanical Engineering at Columbia University in the City of New York where she had also served as Provost from July 2021 to June 2023, Dean of The Fu Foundation School of Engineering and Applied Science at Columbia University in the City of New York, where she is alsofrom July 2013 to June 2021 and the Morris A. and Alma Schapiro Professor of Engineering.Engineering from July 2013 to June 2021. Prior to joining Columbia University in 2013, Dr. Boyce served on the faculty of the Massachusetts Institute of Technology (“MIT”) for over 25 years, leading the Mechanical Engineering Department from 2008 to 2013. She holds a BS degree in engineering science and mechanics from Virginia Tech, and MS and Ph.D. degrees in mechanical engineering from MIT. Dr. Boyce’s research focuses on materials and mechanics, particularly in the areas of multi-scale and nonlinear mechanics of polymers and soft composites, and her work has been documented in over 170 archival journal articles spanning materials, mechanics, and physics. She has mentored over 40 M.S. thesis students and over 25

and Sciences, and the National Academy of Engineering. She is a recipient of the 2015 Engineering Science Medal from the Society of Engineering Science, the 2020 Timoshenko Medal from the Applied Mechanics Division of the American Society of Mechanical Engineers, and the 2024 Benjamin Franklin Medal (for contributions to Mechanical Engineering) from the Franklin Institute. Dr. Boyce also serves on the Advisory Board of The Boston Dynamics Artificial Intelligence Institute, a research institute focused on the frontiers of robotics and artificial intelligence. We believe Dr. Boyce is qualified to serve on our board of directors because of her extensive leadership experience and because she is a distinguished engineer and academic leader in the field of engineering.

Jim F. Anderson has served as a member of our Board since June 2021. Mr. Anderson is the chair of our nominating and governance committee and a member of our compensation committee, roles he has held since June 2021. He is currently employed by Google (an information technology company), where he serves as Vice President for North American Partner Ecosystem and Channels and was a member of the GTM Advisory Board for CapitalG (the independent growth fund affiliated with Alphabet, Google’s parent company) from February 2020 to February 2022. Mr. Anderson has served in an executive position with Google since September 2018. Prior to joining Google, Mr. Anderson served as a Vice President of the cloud service provider business of Hewlett Packard Enterprises (a computer services company) from April 2016 to August 2018. Prior to his work with Hewlett Packard Enterprises, he served as President of the Americas for BAE Systems Applied Intelligence (an organization focused on cybercrime and risk in the connected world) from February 2014 to April 2016. Prior to joining BAE Systems, Mr. Anderson held various executive positions with Cisco Systems (a telecommunications company) from August 2005 to January 2014 and Dell (an information technology company) from February 2002 to October 2004. Prior to Dell, Mr. Anderson had a 13 year career with Hewlett Packard (an information technology company) where he held various positions from September 1988 to January 2002. Mr. Anderson started his professional career with Accenture (a global professional services company) and was there from July 1986 to August 1988. Mr. Anderson holds a master’s degree in business administration from The Wharton School of the University of Pennsylvania and a bachelor’s degree in electrical engineering. and computer science from Princeton University. We believe Mr. Anderson is qualified to serve on our board of directors as a result of his expertise in leveraging emerging Cloud, Artificial Intelligence and Data Analytics technologies, as well as his business knowledge and his background in electrical engineering and computer science.

THE BOARD OF DIRECTORS RECOMMENDS THAT THE STOCKHOLDERS VOTE FOR“FOR” THE ELECTION OF THE CLASS I DIRECTOR NOMINEE.NOMINEES.

Continuing Directors

The following table sets forth the name, age, position and tenure of the directors who are serving for terms that end following the Annual Meeting.

-7-

The following biographical descriptions set forth certain information with respect to directors who are serving for terms that end following the Annual Meeting, based on information furnished to Altair by each director.

Class II Directors Continuing in Office until the 20222025 Annual Meeting

Trace Harrishas served as a member of our Board since August 2016. Ms. Harris is the chair of our compensation committee, a role she has held since January 2017, and a member of our audit committee, a role she has held since August 2018. She alsoMs. Harris serves as director on the board of Ziff Davis, Inc. (Nasdaq: ZD), a digital media and internet company and on the board and as Treasurer of USA Climbing, the national governing board of the sport of competition climbing. Through its sale in July 2022, she served as lead independent director of Bungie, the video game developer of Halo and Destiny. From March 2021 until July 2022, Ms. Harris served as a memberdirector on the board of our nominating and corporate governance committee from April 2017 through August 2018. Ms. Harris currently isAnzu Special Acquisition Corp. I (formerly Nasdaq: ANZUU), a principal at T Harris LLC, which provides strategy and financial consulting, a position she has held since November 2014.special purpose acquisition company focused on transformative technologies for industrial applications. Prior to that, she worked at A-List Services, LLC, an educational services provider, from January 2017 through January 2019, most recently as interim chief executive officer and chief financial officer. Prior to that,her board work, Ms. Harris spent 13 years between September 2001 and November 2014, working in various roles at Vivendi SA,S.A., most recently serving as senior vice president, strategy, financeSenior Vice President, Strategy, Finance and business innovation. Since March 2021,Business Innovation. She was previously Senior Vice President of Strategic Development for Universal Studios Television Group, where she was responsible for international television strategies and launched its first international television network. Prior to Universal Studios, Ms. Harris has served as a directorwas Director of Anzu Special Purpose Acquisition Corp. I, a public special purpose acquisition company (Nasdaq: ANZUU).Finance and Channel Operations for Warner Bros. International Channels. She began her career at JP Morgan in New York. Ms. Harris holds a bachelor’s degree in economics from Stanford University and a master’s degree in business administration with a concentration in finance from the Yale School of Management. We believe Ms. Harris is qualified to serve on our board of directors because of her significant corporate finance, operational and business experience.

Richard HartShekar Ayyarhas served as a member of our Board since April 2017.July 2021. Mr. HartAyyar is the chaira member of our audit committee, nominating and corporate governance committee and a member of our audittechnology committee, roles he has held since April 2017. He has served as InterimJuly 2021. Mr. Ayyar is currently Chairman of the board of directors and the Chief Executive Officer of Vitech,Arrcus, Inc., a private software company focused on business efficiency through superior network connectivity. He has held these roles at Arrcus since Marchjoining the company in September 2021. Mr. Ayyar is also an advisor at NTTVC, a role he has held since May 2021. From January 2021 and hasto May 2022, Mr. Ayyar served as a director of that company since December 2019. He served as a consultant to various companies during the period from November 2018 until he joined Vitech, Inc. Mr. Hart served as the Chief StrategyExecutive Officer of Guidewire Software, Inc., a publicly-traded software company, from March 2018

Development. As part of this role, she is responsible for driving growth and developing business strategies in pursuit of the company’s mission to provide user-owned identity for the world. She also drives partnerships and integrations for Web3 and AI. Ms. Carter joined Unstoppable Domains as Senior Vice President and Channel Chief in December 2021. Ms. Carter is also the Chairman of the board of directors of Girls in Tech, a nonprofit organization, a role she has held since 2015, and an adjunct professor at Carnegie Mellon University Silicon Valley, a role she has held since 2016. Prior to joining Unstoppable Domains, Ms. Carter held various positions at Amazon Web Services, Inc., a subsidiary of Amazon providing cloud-computing services, from April 2017 to December 2021, most recently serving as the Vice President, Public Sector Partners and Programs. Prior to that, Ms. Carter held various positions with IBM Corporation, a computer software and hardware company. Ms. Carter was also the founder and Chief Executive Officer of a managing director at Deutsche BankSilicon Valley startup. Ms. Carter holds a Master of Business Administration degree from May 2004 through November 2013. Mr. Hart holdsthe Harvard Business School and a bachelor’s degree in physicsapplied science and computer science from Duke University. Ms. Carter is also the Universityauthor of PennsylvaniaThe Tiger and a juris doctorate degree from the New York University SchoolRabbit: Harnessing the Power of Law.AI, Web3 and the Metaverse. We believe Mr. HartMs. Carter is qualified to serve on our board of directors because of his significant corporate finance, legalher extensive leadership experience in the software, AI and business experience.cloud computing technology spaces.

Class III Directors Continuing in Office until the 20232026 Annual Meeting

James R. Scapaco-founded our company and has served as Chairman of our Board and our chief executive officerboard of directors since 1992. PriorMr. Scapa has served, and continues to his roleserve, as our chief executive officer, Mr. Scapa served as secretary and treasurerChief Executive Officer since our inception in 1985. Mr. Scapa also previously served as our Secretary and Treasurer. Mr. Scapa holds a bachelor’s degree in mechanical engineering from Columbia University and a masters ofmaster’s degree in business administration degree from the University of Michigan. We believe that the perspective and experience that Mr. Scapa brings as our chief executive officerChief Executive Officer and founderFounder uniquely qualifies him to serve as the Chairman of our board of directors. Mr. Scapa is the father of Stephanie Buckner, who became an executive officer of our company in 2021.2021 and currently serves as our Chief Operating Officer.

SteveStephen Earhart has served as a member of our Board since May 2011. Mr. Earhart is the chair of our audit committee, a position he has held since January 2016, and a member of our compensation committee, a position he has held since January 2015. Mr. Earhart served as a member of the board of directors and audit committee chair of Mi9 Retail, Inc., a private company providing enterprise software solutions to retailers, a position he held from December 2017 to October 2018. Mr. Earhart served as chief financial officerChief Financial Officer of World Kitchen, LLC, a branded consumer products company, from April 2012 to January 2017. From December 2007 to June 2010, Mr. Earhart served as executive vice president and chief financial officerChief Financial Officer of Torex Retail Holdings, Ltd., a retail software provider based in the United Kingdom. From 2003 to 2007, Mr. Earhart served as the Chief Financial Officer of SSA Global Technologies Inc. (formerly Nasdaq: SSAG) and Infor Global Solutions, each an enterprise resource planning software company. In 2003, Mr. Earhart retired from Motorola, Inc., a telecommunications company, as Senior Vice President of Finance. Mr. Earhart is a certified public accountant and holds a bachelor’s degree in business and accounting from the University of Illinois and a master’s degree in business administration from the University of Wisconsin. We believe Mr. Earhart is qualified to serve on our board of directors because of his significant corporate finance, operational and business experience gained from holding senior executive positions at both publicly-tradedpublicly traded and private technology and consumer companies.

CORPORATE GOVERNANCE MATTERS

Board of Director Composition

Our Board currently consists of seven members. Our directors hold office until their successors have been elected and qualified or until the earlier of their resignation or removal.

We have no formal policy regarding board diversity. Our priority in selection of board members is identification of members who will further the interests of our stockholders through his or her established record of professional accomplishment, the ability to contribute positively to the collaborative culture among board members, knowledge of our business and understanding of the competitive landscape.

Board of Director Meetings

Our Board met 13four times in 2020.2023. Each director attended at least 75% of the aggregate of (i) the total number of meetings of our Board (held during the period for which such director served on the Board) and (ii) the total number of meetings of all committees of our Board on which such director served (during the periods for which the director served on such committee or committees). Altair does not have a formal policy requiring members of the Board to attend our annual meetings. All directors attended the 20202023 annual meeting of stockholders, which was held remotely.

Director Independence

Because Mr. Scapa controls a majority of our outstanding voting power, we qualify as a “controlled company” under the corporate governance rules of the NASDAQ Stock Market LLC, or NASDAQ. Therefore, we are not required to have a majority of our Board be independent, nor are we required to have an independent compensation committee or an independent nominating function. Notwithstanding our “controlled company” status, we intend to comply with the majority independence and independent compensation committee and nominating function requirements. Regardless of whether we qualify as a “controlled company”, we are required to have a fully independent audit committee subject to certain transition rules. Additionally, audit committee members must also satisfy the independence criteria set forth in Rule 10A-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

Under the rules of the Nasdaq Global Select Market, a director will only qualify as an “independent director” if, in the opinion of that company’s board of directors, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. In order to be independent, compensation committee members must not have a relationship with the issuer that is material to the director’s ability to be independent from management in connection with the duties of a compensation committee member.

In order to be considered independent for purposes of Rule 10A-3, a member of an audit committee of a listed company may not, other than in his or her capacity as a member of the audit committee, the board of directors or any other board committee, accept, directly or indirectly, any consulting, advisory or other compensatory fee from the listed company or any of its subsidiaries or be an affiliated person of the listed company or any of its subsidiaries.

Our Board has undertaken a review of the independence of each director. Based on information provided by each director concerning his or her background, employment and affiliations, our Board determined that Messrs. Anderson, Ayyar and Earhart, Hartand Kowal, who is not standing for reelection at the Annual Meeting,Mses. Carter and Ms. Harris, and Dr. Boyce do not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director and that each of these directors is “independent” as that term is defined under the applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) and the listing

Select Market. In making these determinations, our Board considered the current and prior relationships that each non-employee director has with our company and all other facts and circumstances our Board deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director, and any transactions involving them described in the section entitled “Transactions with Related Persons.”

Board Committees

Audit Committee

Our audit committee currently consists of Messrs. Earhart, as chair, and HartAyyar and Ms.Mses. Carter and Harris, each of whom is “independent” as that term is defined under applicable SEC rules and NASDAQ listing standards. Our Board has determined that Mr. Earhart qualifies as an audit committee financial expert within the meaning of SEC regulations and The NASDAQ Marketplace Rules. In making this determination, our Board has considered the formal education and nature and scope of his previous experience, coupled with past and present service on various audit committees. Our audit committee assists our Board in its oversight of our accounting and financial reporting process and the audits of our financial statements.

Our audit committee’s responsibilities include:

All audit services to be provided to us and all non-audit services to be provided to us by our independent registered public accounting firm must be approved in advance by our audit committee.

Our audit committee operates pursuant to a charter that is available on our website at http://investor.altair.com under the Governance section. Our audit committee met 12eight times in 2020.2023.

Compensation Committee

Our compensation committee currently consists of Ms. Harris, as chair, and Messrs. EarhartAnderson and Kowal, who is not standing for reelection at the annual meeting,Earhart, each of whom is “independent” as that term is defined

Our compensation committee assists our Board in the discharge of its responsibilities relating to the compensation of our executive officers. Our compensation committee’s responsibilities include:

Our compensation committee operates pursuant to a charter that is available on our website at http://investor.altair.com under the Governance section. Our compensation committee met 13seven times in 2020.2023.

Nominating and Corporate Governance Committee

Our nominating and corporate governance committee currently consists of Messrs. Hart,Anderson, as chair, and Kowal, who is not standing for reelection at the Annual Meeting,Ayyar, and Ms. Carter, and Dr. Boyce, each of whom is “independent” as that term is defined under applicable NASDAQ listing standards. The nominating and corporate governance committee’s responsibilities include:

Our nominating and corporate governance committee operates pursuant to a charter that is available on our website at http://investor.altair.com under the Governance section. Our nominating and corporate governance committee met 4four times in 2020.2023.

Technology Committee

Our technology committee currently consists of Dr. Boyce, as chair, and Messrs. KowalMr. Ayyar and Chouinard, neither of whom are standing for reelection at the annual meeting.Ms. Carter. The technology committee’s responsibilities include:

Stockholder Nominations for Directorships

Our nominating and corporate governance committee will consider potential director candidates recommended by stockholders as long as the stockholders comply with our certificate of incorporation and bylaws, in recommending a potential candidate. Stockholders who wish to recommend a candidate for nomination should contact our corporate secretary in writing and provide the following information:

Assuming that appropriate information is provided for candidates recommended by stockholders on a timely basis, our nominating and corporate governance committee will evaluate those candidates by following substantially the same process, and applying substantially the same criteria, as for candidates submitted by members of the Board or other persons, as described above and as set forth in its charter.

Board Diversity

The following Board Diversity Matrix presents our Board diversity statistics in accordance with Nasdaq Rule 5606. The information is based on our directors’ self-reporting and reflects compliance with the objectives of Nasdaq Rule 5605(f)(3) by having at least one director who identifies as female and at least one director who identifies as a member of an Underrepresented Minority (as defined by Nasdaq Rules). As we pursue future Board recruitment efforts, our nominating and corporate governance committee will continue to seek candidates who can contribute to the diversity of views and perspectives of the Board. This includes seeking out individuals of diverse ethnicities, a balance in terms of gender, and individuals with diverse perspectives informed by other personal and professional experiences.

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Board Leadership Structure and Role in Risk Oversight

The chief executive officer and Chairman positions are held by James Scapa. Mr. Scapa also beneficially owns approximately 52.2%52.6% of the voting power of our common stock. Periodically, our Board assesses these roles and the Board leadership structure to ensure the interests of Altair and our stockholders are best served. Our Board has determined that its current leadership structure is appropriate. James Scapa, as one of our founders and as our chief executive officer and Chairman, has extensive knowledge of all aspects of Altair, our business and risks, and our customers. Our Board has no Lead Independent Director; however, the Board may choose to elect one.

While management is responsible for assessing and managing risks to Altair, our Board is responsible for overseeing management’s efforts to assess and manage risk. This oversight is conducted primarily by our full

Communications from stockholders will be forwarded to all directors if they relate to important substantive matters or if they include suggestions or comments that the Secretary considers to be important for the Board to know. Communication relating to corporate governance and corporate strategy are more likely to be forwarded to the Board than communications regarding personal grievances, ordinary business matters, and matters as to which Altair tends to receive repetitive or duplicative communications.

Stockholders who wish to send communications to the Board should address such communications to: The Board of Directors, Altair Engineering Inc., 1820 East Big Beaver Road, Troy, Michigan 48083, Attention: Secretary.

Code of Business Conduct and Ethics

We maintain a written code of business conduct and ethics that applies to our directors, officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. A current copy of the code is posted on the Governance section of our website, which is located at http://investor.altair.com. If we make any substantive amendments to, or grant any waivers from, the code of business conduct and ethics for any officer or director, we will disclose the nature of such amendment or waiver on our website or in a current report on Form 8-K.

Compensation Committee Interlocks and Insider Participation

Our compensation committee currently consists of Ms. Harris, as chair, and Messrs. EarhartAnderson and Kowal, who is not standing for reelection at the Annual Meeting.Earhart. No member of our compensation committee is or has been an officer or employee of Altair. None of our executive officers currently serves, or during fiscal 2020 has2023 served, as a member of the compensation committee or director (or other board committee performing equivalent functions or, in the absence of any such committee, the entire board of directors) of any entity that has one or more executive officers serving on our compensation committee or our Board.

EXECUTIVE OFFICERS

The following table sets forth certain information regarding our current executive officers:

Our executive officers are elected by, and serve at the discretion of, our Board. The business experience for the past five years, and in some instances, for prior years, of each of our executive officers is as follows:

James R. Scapa has served, and continues to serve, as our Chief Executive Officer since 1992.our inception in 1985. For Mr. Scapa’s biography, please see the section above entitled “Class III Nominees Continuing in Office until the 20232026 Annual Meeting.”

Brett Chouinard has served as our President since January 1, 2018 and as a member of our board of directors since 2018. He is also our Chief Operating Officer, a position he has held since January 2010. In January 2021, we announced that Mr. Chouinard will transition to the role of serving as one of our Chief Technology Officers by the end of June, 2021. Prior to his role as our chief operating officer, Mr. Chouinard served in various roles with us since 1994. Prior to joining us, Mr. Chouinard worked as an engineer at GE Aircraft, a subsidiary of General Electric, Inc. specializing in aircraft engines. Mr. Chouinard holds a bachelor’s degree in mechanical engineering from Michigan Technological University and a master’s degree in mechanical engineering from the University of Cincinnati.

Matthew Brown has served as our Chief Financial Officer since March 16, 2021. Prior to this role, Mr. Brown served from January 1, 2021, to March 16, 2021after serving as one of our Senior Vice Presidents-Finance.Presidents—Finance since January 1, 2021. Prior to joining our company, Mr. Brown served in Finance leadership roles at NortonLifeLock, a leading consumer cyber safety company, including as Interim Chief Financial Officer from November 2019 to July 2020. Prior to that, he served in Finance leadership roles at Symantec, a leading provider of enterprise security software, from August 2016 to November 2019, most recently as Vice President of Finance and Chief Accounting Officer. Prior to that, Mr. Brown served as Vice President, Controller for Blue Coat Systems, a provider of advanced web security solutions, from October 2015 to August 2016. Prior to that, Mr. Brown served in various Finance roles at NETGEAR (2010 to 2015) and Brocade Communications (2008 to 2010). He began his career at KPMG, LLP. Mr. Brown is a certified public accountant and holds a Bachelor of ScienceB.S. degree in business administration from the Walter A. Haas School of Business at the University of California, Berkeley.

James P. DaggStephanie Buckner has served as our Chief TechnicalOperating Officer of modeling and visualization since January 2014.1, 2022 and is responsible for our corporate development efforts and field operations, sales and technical support globally. Prior to this role, Mr. DaggMs. Buckner served as our Senior Vice President of Customer Engagement and Corporate Development from May 2008January 2021 to December 2013January 2022. Prior to this role, Ms. Buckner served as theour senior vice president of our wholly-owned subsidiary solidThinking, Inc. Mr. Daggcorporate development from January 2019 to January 2021. Ms. Buckner joined Altair in June 2011 as a partner solutions manager. Ms. Buckner holds a bachelor’s degree in mechanicalindustrial and operations engineering and a master’s degree in applied mechanics from the University of Michigan.

Nelson Dias has served as our Chief Revenue Officer since January 1, 2018, after serving as our Senior VP—Asia Pacific since 2006. Prior to running Altair’s APAC region, Mr. Dias was Managing Director of Altair India from 2002-2005. He has over 2834 years of technical sales and management experience. Mr. Dias holds a Bachelor of Engineering in Computer Science degree from the University of Mumbai.

Amy Messano has served as our Chief Marketing Officer since January of7, 2019. Prior to joining Altair, Ms. Messano served as vice presidentVice President of marketing/communicationsMarketing/Communications for the Electronics and Safety division at Aptiv PLC (formerly Delphi), a global technology company, from 2012 to 2013, and then as vice president,Vice President, Integrated Marketing and Communications from 2014 to 2018 where she was primarily responsible for global marketing teams supporting marketing campaigns, messaging and supporting materials as well as distribution, and was also responsible for web, digital marketing, social media, media relations and content creation globally. Ms. Messano holds a bachelor’s degree in history and English from the University of Colorado, Boulder, and a master’s of science, journalism from Northwestern University.

Dave Simon has served as our Chief Administrative Officer since January of 2019. Prior to this role, Mr. Simon served as a senior vice president of Altair in charge of corporate talent and communications from 2018 to 2019, vice president of corporate communications from 2016-2018, president of Altair’s wholly-owned subsidiary ilumisys, Inc. (d/b/a toggled) from 2008 to 2016, director of product innovation from 2004-2008, and vice president—enterprise process management from 2002-2004. He has over 34 years of industry experience, and was with Altair from 1986-1990 prior to rejoining the company in 2000. Mr. Simon holds a bachelor’s degree in aerospace engineering from the University of Michigan, and a masters in management from Walsh College.

Raoul Maitrahas served as our Chief Legal Officer since February of 2020. Previously, he served as our Co-General Counsel from April 2015 until 2020. He joined our company in 2006 as Deputy General Counsel and served in that capacity until 2015. Mr. Maitra holds a bachelor’s degree in political science from the University of Michigan and a Juris Doctor degree from the Mauer School of Law at Indiana University (Bloomington).

Gilma Saravia became has served as our Chief People Officer insince February 2020. Prior to joining Altair, she served as vice president, global corporate human resourcesVice President, Global Corporate Human Resources and talent,Talent, for Aptiv PLC, a global technology company, from 2015 to 2019. Prior to her employment by Aptiv, Ms. Saravia held executive roles at U. S. Steel (2011 to 2015) and served as a senior manager in Deloitte’s Human Capital consulting group (2002 to 2011). Ms. Saravia holds a degree in business administration degree from the University of Texas at Austin.

Stephanie Buckner has served as our Senior Vice President of Customer Engagement and Corporate Development since January 2021. Prior to this role, Ms. Buckner served from January 2019 to January 2021 as the senior vice president of corporate development. Ms. Buckner joined Altair in June 2011 as a partner solutions manager. Ms. Buckner holds a bachelor’s degree in industrial and operations engineering from the University of Michigan. Ms. Buckner is the daughter of James Scapa, our founder, Chairman and Chief Executive Officer.

Brian Gaylehas served as our Senior Vice President, Chief Accounting Officer since September 2018 and also became our principal accounting officer in March 2021. From March 2015 to September 2018, Mr. Gayle

EXECUTIVE COMPENSATION

Compensation Discussion and Analysis

Introduction

This Compensation Discussion and Analysis provides information regarding the 20202023 compensation program for our principal executive officer, our principal financial officer and the three other most highly-compensated executive officers (our “Named Executive Officers”). For 2020,2023, our Named Executive Officers were:

Mr. Morof was our CFO until March 16, 2021. At the close of business on March 16, 2021, Matthew Brown became our CFO.

This Compensation Discussion and Analysis describes the material elements of our executive compensation program during 2020.2023. It also provides an overview of our executive compensation philosophy, including our principal compensation policies and practices. Finally, it analyzes how and why the Compensation Committee of our Board of Directors (the “Compensation Committee”) arrived at the specific compensation decisions for our Named Executive Officers in 2020,2023 and discusses the key factors that the Compensation Committee considered in determining their compensation.

Executive Summary

Who We Are

We are a global technology company providingleader in computational science and artificial intelligence enabling organizations across broad industry segments to drive smarter decisions in an increasingly connected world. We deliver software and cloud solutions in the areas of simulation and design, high-performance computing (HPC)(“HPC”), data analytics, and artificial intelligence (AI)(“AI”). We enable organizations across broad industry segmentsOur products and services leverage computational intelligence to compete more effectively in a connected world while creatingdrive innovation for a more connected, safe, and sustainable future.

We refer to AI as a term to encompass sub-disciplines including data analytics, data science, data preparation, and machine learning.learning (ML). Altair has been incorporating AI technologies into our products for several years and we believe the evolving broad use of the term is appropriate for our product offerings, customer applications, and market opportunities.

Our simulation and AI-driven approach to innovation is powered by our broad portfolio of high-fidelity and high-performance physics solvers, our market leading technology for optimization and HPC, and our end-to-end platform for developing AI and Internet of Things (IoT)digital twin solutions. Our integrated suite of software optimizes design performance across multiple disciplines encompassing structures, motion, fluids, thermal, electromagnetics, system modeling, and embedded systems, while also providing AI solutions and true-to-life visualization and rendering. Our HPC solutions maximize the efficient utilization of complex compute resources and streamline the workflow management of compute-intensive tasks for applications including AI, modeling and simulation, and visualization. Our data analytics, AI, and IoTInternet of Things (IoT) products include data preparation, data science, MLOps, orchestration, and visualization solutions that fuel engineering, scientific, and business decisions.

2023 Business Results

2020 wasWe achieved strong business results in 2023 driven by momentum across a strong year for us, reflecting continuing growthnumber of our software platforms and integration of important acquired technologies as we confronted the business and personal safety challenges imposed by COVID-19.verticals, where computational intelligence is becoming increasingly important. In 2020:2023:

A reconciliation of the GAAP and non-GAAP information referenced above is set forth in Appendix A to this Proxy Statement. Our compensation determinations for 20202023 were based, in part, on our 20202023 performance.

Executive Compensation Results

The Compensation Committee took the following key actions with respect to the compensation of our Named Executive Officers in 2020:2023:

We emphasize variable compensation that appropriately rewards our executive officers, including our Named Executive Officers, through two separate compensation elements:

These variable pay elements assure that a meaningful portion of our executive officers’ target total direct compensation is contingent (rather than fixed) in nature, with the amounts ultimately payable subject to variability above or below target levels commensurate with our actual performance.

We believe that this design provides balanced incentives for our executive officers to drive financial performance and long-term growth.

Executive Compensation Policies and Practices

We endeavor to maintain sound governance standards in the design and implementation of our executive compensation policies and practices. The Compensation Committee evaluates our executive compensation program on a regular basis to ensure that it is consistent with our short-term and long-term goals, given the dynamic nature of our business and the market in which we compete for executive talent. The following summarizes our executive compensation and related policies and practices:

What We Do

What We Do Not Do

Stockholder Advisory Votes on Named Executive Officer Compensation

We are required to conduct non-binding stockholder votes on the compensation of our Named Executive Officers (commonly known as a “Say-on-Pay”“Say-on-Pay” vote). At our 2019 annual meeting of stockholders, we conducted a non-binding stockholder vote on the frequency of future Say-on-Pay votes (commonly known as a “Say-When-on-Pay” vote). We recommended that such votes be conducted annually and our stockholders overwhelmingly approved that recommendation. We will hold a Say-on-Pay vote at each annual meeting until the time our stockholders vote to hold the Say-on-Pay vote at a different frequency. See Proposal 32 in this Proxy Statement.

At the 20202023 Annual Meeting, approximately 98% of the votes cast in connection with the stockholders advisory vote on compensation of the NEOs were cast in favor of the proposal. We value the opinions of our stockholdersstockholders. We have considered this voting result, and our Board of Directors and the Compensation Committee will consider the outcome of future Say-on-Pay votes, as well as feedback received throughout the year, when making compensation decisions for our executive officers, including our Named Executive Officers.

Executive Compensation Philosophy and Objectives

Our executive compensation program is guided by our overarching philosophy of paying for demonstrable performance. Consistent with this philosophy, we have designed our executive compensation program to achieve the following primary objectives:

Program Design

We structure the annual compensation of our executive officers, including our Named Executive Officers, using three principal elements: base salary, a cash bonus award pursuant to our executive bonus program, and long-term incentive compensation opportunities in the form of equity awards. While the pay mix may vary from year to year, the ultimate goal is to achieve our compensation objectives as described above. In determining the amount of base salary, cash bonuses, and equity compensation awarded to each Named Executive Officer, the Compensation Committee does not apply any strict percentage of any one element in relation to the overall compensation package. Instead, the Compensation Committee reviews the overall compensation package and the relative amount of each element on an individual basis for each Named Executive Officer to determine whether such amounts, and the mix of compensation components, further the basic principles and objectives of our overall compensation program.

recommends for Board of Director approval compensation for the non-employee members of our Board of Directors. The Compensation Committee has overall responsibility for overseeing our compensation and benefits policies generally, and overseeing and evaluating the compensation plans, policies, and practices applicable to our CEO and other executive officers. In addition, the Compensation Committee makes all final decisions regarding the compensation of our CEO and other executive officers. The Compensation Committee is also responsible for the administration of our 2021 Employee Stock Purchase Plan (the “ESPP”), in which employees participate on a voluntary basis.

In carrying out its responsibilities, the Compensation Committee evaluates our compensation policies and practices with a focus on the degree to which these policies and practices reflect our executive compensation philosophy, develops strategies and makes recommendations that it believes further our philosophy or align with developments in best compensation practices.

The Compensation Committee’s authority, duties, and responsibilities are further described in its charter, which is reviewed annually and revised and updated as warranted. The charter is available on our website at http://investor.altair.com.

The Compensation Committee retains a compensation consultant (as described below) to provide support in its review and assessment of executive compensation as needed.

Setting Target Total Direct Compensation

The Compensation Committee reviews the base salary levels, annual incentive bonus payments and long-term incentive compensation opportunities of our executive officers, including our Named Executive Officers, and related performance criteria.

The Compensation Committee does not establish a specific target for formulating the target total direct compensation opportunities of our executive officers. In making decisions about the compensation of our executive officers, the Compensation Committee relies primarily on its members’ general experience and expertise, on the advice of consultants and other advisors and its consideration of a number of factors, including the following:

determinations with respect to our executive officers. Instead, in making recommendations and determinations, the Compensation Committee reviews information summarizing the compensation paid at a representative group of peer companies, to the extent that the executive positions at these companies are considered comparable to our positions and informative of the competitive environment, and more broad-based compensation surveys to gain a general understanding of market compensation levels.

In addition, the Compensation Committee does not weight the foregoing factors in any predetermined manner, nor does it apply formulas in making its compensation determinations. The members of the Compensation Committee consider all of this information in light of their individual experience, knowledge of the Company and its business results, knowledge of the competitive market, knowledge of each executive officer, the advice of their compensation consultant and their business judgment in making their recommendations and determinations.

As part of its oversight function, our Board and our Compensation Committee, in particular, along with our management team, considers potential risks when reviewing and approving various compensation programs, including executive compensation. Based on this review, our Compensation Committee believes that our compensation programs, including executive compensation, do not encourage risk taking to a degree that is reasonably likely to have a materially adverse impact on us or our operations.

Role of Management

In discharging its responsibilities, the Compensation Committee works with our CEO, who assists the Compensation Committee by providing information on corporate and individual performance, perspectives on performance issues and recommendations on compensation matters.

Typically, our CEO will make recommendations to the Compensation Committee regarding compensation matters, including adjustments to annual cash compensation, long-term incentive compensation opportunities, and program structures, for our executive officers, including our other Named Executive Officers. At the beginning of each year, our CEO reviews the performance of our executive officers based on each such individual’s level of success in accomplishing the business objectives established for him or her for the prior year and his or her overall performance during that year, and then shares these evaluations with, and makes recommendations to, the Compensation Committee for each element of compensation as described above. The Compensation Committee reviews and discusses these recommendations and proposals with our CEO.

Our CEO attends meetings of the Compensation Committee at which executive compensation matters are addressed, but does not participate in the Compensation Committee’s deliberations involving his own compensation.

Role of Compensation Consultant

The Compensation Committee has, from time to time, engaged an external compensation consultant to assist it by providing information, analysis, and other advice relating to our executive compensation program. When engaged, the compensation consultant reports directly to the Compensation Committee and its chair, and serves at the discretion of the Compensation Committee, which reviews the engagement on a periodic basis.

the Compensation Committee evaluatedengages Compensia, the Compensation Committee evaluates Compensia’s engagement and based on the six factors for assessing independence and identifying potential conflicts of interest that are set forth in Exchange Act Rule 10C-1(b)(4), Rule 5605(d)(3)(D) of the NASDAQ Marketplace Rules, and such other factors as wereare deemed relevant under the circumstances, determined that its relationship with Compensia and the work of Compensia on behalf of thecircumstances. The Compensation Committee did not raise any conflict of interest, and that Compensia is independent.undertake this review in 2023.

Competitive Positioning

For purposes of assessing our executive compensation against the competitive market, the Compensation Committee reviews and considers the compensation levels and practices of a select group of peer companies. This compensation peer group consists of technology companies that share one or more characteristics of our company, including annual revenue, market capitalization, geographical location, vertical focus and end market. However, not all criteria may be applicable to each individual peer group member. The Compensation Committee reviews our compensation peer group from time to time, generally, every other year, and makes adjustments to its composition as warranted, taking into account changes in both our business and the businesses of the companies in the peer group. The inclusion of a peer company in one year does not subsequently mean it will be included in other years. We included the following companies in our group of peer companies for 20202023 compensation purposes:

The compensation practices of the then current compensation peer group are used by the Compensation Committee as a guide to compare the competitiveness of each compensation element and overall compensation levels (base salary, target annual incentive bonus opportunities, and long-term incentive compensation). To analyze the compensation practices of the companies in our compensation peer group, Compensia gathers data from public filings (primarily proxy statements) of the peer group companies, as well as survey data from Compensia’s proprietary database. This market data is then used as a reference point for the Compensation Committee to assess our compensation levels in the course of its deliberations on compensation forms and amounts.

Base Salary

Base salary represents the fixed portion of the compensation of our executive officers, including our Named Executive Officers, and is an important element of compensation intended to attract and retain highly-talented individuals. Generally, we use base salary to provide each executive officer with a specified level of cash compensation during the year with the expectation that he or shethe Named Executive Officer will perform his or her responsibilities to the best of his or her ability and in our best interests.

Generally, we establish the initial base salaries of our executive officers through arm’s-length negotiation at the time we hire the individual, taking into account his or her position, qualifications, experience, and the base salaries of our other executive officers. Thereafter, the Compensation Committee reviews the base salaries of our executive officers each year as part of its annual compensation review, with recommendations from our CEO (except with respect to his own base salary) and makes adjustments as it determines to be reasonable and necessary to reflect the scope of an executive officer’s performance, individual contributions and responsibilities, position in the case of a promotion, and market conditions.

In March 2020,2023, the Compensation Committee reviewed the base salaries of our executive officers, including our Named Executive Officers, taking into consideration the factors described in “Compensation-Setting Process – Setting Target Total Direct Compensation” above. Following this review, the Compensation Committee approved base salary increases for certain of our executive officers. Ms. Saravia did not receive a base salary increase in 2020 given that she became employed by Altair in February 2020.

discretion of the Compensation Committee based upon the attainment of performance objectives as proposed by the CEO and approved by the Compensation Committee and which relate to the financial metrics that are most important to us.

Generally, for the Named Executives other than the CEO, bonus payments under the Executive Bonus Program are calculated starting with a target bonus amount for each participant as recommended by our CEO and approved by the Compensation Committee, multiplied by the achievement of a corporate financial performance metric andCommittee. Bonuses are then for each program participant, adjusted for his or her individual performance. For the CEO, the Compensation Committee begins with a target bonus amount and then evaluates the CEO’s performance against certain quantitative and qualitative metrics associated with Company and individual performance.In each case, the Compensation Committee reviews the payment and amount of any award.

For 2020, Mr. Morof, Ms. Messano and Dr. Schramm were paid 50% of their target bonus payment under the Executive Bonus Program in equal monthly installments, with the additional earned bonus paid once final bonus amounts weregenerally determined after the end of the year. The CEO and Ms. Saravia did not receive any portion of their bonuses until after the final bonus amounts were determined subsequent to year-end. No provision was made for repayment of these installments if 2020 performance objectives were not attained; in fact, the performance objectives utilized by the Compensation Committee in 2020 were largely attained. Commencing in 2021, bonus payments will not be paid to our executive officers until the final bonus amounts are calculated.

Target Bonus Amounts

For purposes of the Executive Bonus Program, bonus payments are based upon a specific target bonus amount as recommended by our CEO and approved by the Compensation Committee. The CEO participates in the Compensation Committee’s deliberations regarding the target amounts for eligible employees, but does not participate in the deliberations regarding his target bonus.

In March 2020, the Compensation Committee reviewed the recommended target bonus amounts for our Named Executive Officers, taking into consideration the factors described in “Compensation-Setting Process – Setting Target Total Direct Compensation” above. Following this review, the Compensation Committee determined to set the target bonus amounts as proposed by our CEO with respect to the Named Executive Officers other than himself. The Compensation Committee independently reviewed and determined the CEO’s target bonus. For 2020, the target bonus amounts for our Named Executive Officers were as follows:

our CEO throughout 2020.2023. For 2023, no adjustments were made to adjusted EBITDA in setting the Company Performance Target or in measuring the Company’s financial results relative to the Company Performance Target.

Based on these determinations, the Compensation Committee approved the following cash bonus payments for our Named Executive Officers for 2020:2023:

Other than the amounts described above, we did not pay our Named Executive Officers any other annual cash bonuses with respect to 20202023 performance.

Long-Term Incentive Compensation

We view long-term incentive compensation in the form of equity awards as a critical element of our executive compensation program. The realized value of these equity awards bears a direct relationship to our stock price, and, therefore, these awards are an incentive for our executive officers, including our Named Executive Officers, to create value for our stockholders. Equity awards also help us retain qualified executive officers in a competitive market.

The equity awards granted to our Named Executive Officers in March 2023 and to Mr. Brown in December 2023 were as follows:

In March 2024, the Compensation Committee determined that the equity awards to be granted to our executive officers, including our Named Executive Officers, should be a combination of time-based RSU awards that may vest and be settled for shares of our Class A Common Stock and options to acquire our Class A Common Stock. The number of shares of our Class A Common Stock subject to the RSU awards and options granted to our executive officers were proposed by the CEO and approved by the Compensation Committee (with Mr. Scapa participating in determinations regarding the grants other than the grants made to him) after considering the factors described in “Compensation-Setting Process” above. All of the RSU awards and options were granted in March 2024 with respect to 2023 performance. Under applicable SEC regulations, such equity awards are not included in the Summary Compensation Table below as 20202023 compensation.

The equity awards granted to our Named Executive Officers in March 20212024 were as follows:

The time-based RSU awards and stock options vest in equal annual installments over a four-year period, with each installment vesting on the anniversary of the date of grant, contingent upon each Named Executive Officer’s remaining continuously employed by us through each applicable vesting date. Upon vesting, the RSU awards may be settled by issuing that number of shares of our Class A Common Stock that equal the number of units that have vested.

Health and Welfare Benefits

Our US-based Named Executive Officers are eligible to receive the following health and welfare benefits: a flexible spending account, a dependent care account, medical, dental, and vision insurance, business travel insurance, an employee assistance program, accidental death and dismemberment insurance, short-term and long-term disability insurance and basic life insurance.

We have also establishedSince 1987, Altair has offered a tax-qualified 401(k) retirement savings plan (the “401(k) Plan”) for our US-based employees, including our US-based executive officers and our US-based Named Executive Officers, and other employees who satisfy certain eligibility requirements. In 2022, Altair added the Roth 401(k) feature to the 401(k) Plan. The Roth feature allows our employees to invest post-tax dollars and in retirement, access their money tax free. Under this plan,the 401(k) Plan, participants may elect to make pre-tax contributions of up to 80% of their eligible compensation, subject to the statutory income tax limits. The 401(k) Plan permits us to make discretionary matching contributions and discretionary contributions to eligible participants, subject to five-year graded vesting: 20% vests after one year, 40% after two years, 60% after three years, 80% after four years, and 100% after five

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years. The 401(k) Plan has an automatic enrollment feature for all employees hired on or after April 1, 2014, automatically withholding elective deferrals equal to 3%4% of eligible compensation, unless the participant affirmatively changes the deferral amount. We intend for the plan401(k) Plan to qualify under Section 401(a) of the Internal Revenue Code (the “Code”) so that contributions by participants to the plan,401(k) Plan, and income earned on planthose contributions, are not taxable to participants until withdrawn from the plan.401(k) Plan.

We design our employee benefits programs to be affordable and competitive in relation to the market as well as compliant with applicable laws and practices. We adjust our employee benefits programs as needed based upon regular monitoring of applicable laws and practices and the competitive market.

Perquisites and Other Personal Benefits

During 2020, theThe Company acquiredowns a fractional interest in an airplane intended to be used primarily for business travel by our chief executive officerCEO and by other employees travelling with our chief executive officer.CEO, and which may be used by other employees with the approval of our CEO. We believe that use of the Company airplane enhances personal safety and increases time available for business purposes. Our chief executive officerCEO and his guests may use our corporate airplane for non-business purposes. For 2020,2023, the aggregate incremental cost to Altair of our CEO’s personal use of our corporate airplane was $35,453.$175,283. No other Named Executive Officers made personal use of our corporate airplane during 2020.2023.

termination by the Company other than for “cause” or in the event of a resignation by the applicable Named Executive Officer for “good reason” during the period between the execution of the Severance Agreements and the one-year anniversary of a “change in control.” In such event, the executive generally would be entitled to the following (in lieu of any other severance payments to which the executive may be entitled), subject to execution of a release of claims (other than with respect to certain amounts that accrued prior to termination):

The Severance Agreements provide that to the extent any amount or benefit to be provided pursuant to the applicable Severance Agreement or otherwise would be treated as an “excess parachute payment,” as that phrase is defined in Section 280G of the Code, then the amounts and benefits the executive would otherwise receive would either be (i) paid or allowed in full; or (ii) reduced (but not below zero) to the maximum amount which may be paid without causing any amount or benefit to be nondeductible to the Company under Section 280G of the Code, or subject the executive to an excise tax under Section 4999 of the Code, whichever would result in the executive’s receipt, on an after-tax basis, of the greatest amount of amounts and benefits.

Tax and Accounting Considerations

We may take applicable tax and accounting requirements into consideration in designing and operating our executive compensation program.

20202023 Summary Compensation Table

Our Named Executive Officers for the year ended December 31, 20202023 are: James R. Scapa, Howard N. Morof, Gilma Saravia, Amy Messano and Uwe Schramm. Mr. Morof served as our Chief Financial Officer through March 16, 2021. At the close of business on March 16, 2021, Matthew Brown, became our Chief Financial Officer.Stephanie Buckner, Mahalingam Srikanth and Nelson Dias. The following table provides information regarding the total compensation for services rendered in all capacities earned by our Named Executive Officers for the fiscal years ended December 31, 2020, 20192023, 2022 and 2018.2021.

Narrative Disclosure to Summary Compensation Table

Employment AgreementsOffer Letters with our Named Executive Officers

James Scapa and Uwe Schramm

Mr. Scapa and Dr. Schramm areis not a party to an employment agreement or offer letter with Altair.

Howard N. Morof Employment Letter

We entered into an employment letter with Howard N. Morof, our former chief financial officer, on January 10, 2013, which was subsequently amended and restated on July 19, 2017, to, among other things, reflect his current compensation and to add language to address provisions of Section 409A of the Internal Revenue Code of 1986, as amended (the “Code”). The employment letter had an indefinite term, and Mr. Morof’s employment was at-will.

During his employment with us, Mr. Morof was entitled to an automobile allowance and was eligible to earn annual incentive compensation payable from our Executive Bonus Program applicable to other members of our senior executive team. He was also eligible to earn a matching contribution to our 401(k) Plan as determined annually by us. His compensation as described in this paragraph was subject to adjustment year to year as described in the section entitled “Compensation, Discussion and Analysis”.

In connection with the termination of Mr. Morof’s services, we entered into a transition and separation and general release agreement with him on January 15, 2021. For information regarding this agreement, see “Compensation Disclosure and Analysis – Post-Employment Compensation”.

Offer Letter with Amy MessanoMatthew Brown

We are parties to an employmentoffer letter with Amy Messano,Matthew Brown, our chief marketingfinancial officer. The employment letter has an indefinite term and Ms. Messano’sMr. Brown’s employment is at-will.

Ms. MessanoMr. Brown is entitled to an automobile allowance and shehe is currently eligible to earn annual incentive compensation payable from our Executive Bonus Program applicable to other members of our senior executive team. SheHe is also eligible to earn a matching contribution to our 401(k) Plan. HerHis compensation may be adjusted year to year.

If Ms. Messano is terminated without cause, her employment letter provides that she is entitled to three months’ base salary, subject to her execution ofWe have also entered into a release of any and all claims relating to her employment. Her employment letter also provides that in the event of Ms. Messano’s termination without cause, all of Ms. Messano’s restricted stock units which are unvested as of the date of Ms. Messano’s termination will vest. Subsequently, these portions of her offer letter were superseded by her severance agreement which is discussed in with Mr. Brown. For more information about his severance agreement, see “Post-Employment Compensation” above.

Offer Letter with Gilma SaraviaStephanie Buckner

We are parties to an employmentoffer letter with Gilma Saravia,Stephanie Buckner, our chief peopleoperating officer. The employmentoffer letter has an indefinite term and Ms. Saravia’sBuckner’s employment is at-will.

Ms. Saravia is entitled to an automobile allowance and she is currently eligible to earn annual incentive compensation payable from our Executive Bonus Program applicable to other members of our senior executive team. She is also eligible to earn a matching contribution to our 401(k) Plan.

We subsequently entered into a severance agreement with Ms. Saravia.Buckner. For more information about her severance agreement, see “Post-Employment Compensation” above.

Potential Payments Upon Termination or Change in Control

The table below reflects, as applicable, cash severance, equity acceleration, and continuation of employment benefits payable to our Named Executive Officers in connection with (A) an involuntary termination of employment (i.e., a termination without cause or resignation for good reason) other than in connection with a change in control of our company, (B) a change in control of our company and no termination of employment (assuming that all equity awards will not be assumed, continued or substituted by the successor entity), and (C) an involuntary termination (i.e., a termination without cause or resignation for good reason) in connection withimmediately following a change in control of our company, assuming for each of (A), (B) and (C) that the applicable triggering event(s) occurred on December 31, 2020,2023, and that the above-mentioned severance agreements were in effect on that date. Generally, however, on any termination, the applicable Named Executive Officer would have received accrued and unpaid salary and other benefits until the date of termination. In addition, the table below assumes that our Named Executive Officers comply with all applicable restrictive covenants.