X0306 4/A 2019-10-18 2019-10-22 0 0001701732 Altair Engineering Inc. ALTR 0001720809 Christ Revocable Trust C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER ROAD TROY MI 48083 0 0 1 0 Class B Common Stock 0.00 2019-10-18 4 C 0 20194 0.00 D Class A Common Stock 20194 7966534 D This amended Form 4 being filed to correct a typo in Table II, Column 4. Each share of Class B common stock is immediately convertible, at the option of the shareholder, into one share of Class A common stock and shall automatically convert into Class A common stock upon the occurrence of certain events. Please see Altair Engineering Inc. Registration Statement filed with the Securities and Exchange Commission on Form S-1 (File No. 333-225412) for a description of the conversion rights. /s/ Raoul Maitra attorney-in-fact for Christ Revocable Trust dated May 8, 2015 2019-10-23