X0306 4 2023-03-01 0001701732 Altair Engineering Inc. ALTR 0001766979 Brown Matthew Charles C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER RD. TROY MI 48083 1 Chief Financial Officer Class A Common Stock 2023-03-01 4 S 0 2173 63.84 D 35925 D Class A Common Stock 2023-03-01 4 S 0 348 63.84 D 35577 D Class A Common Stock 2023-03-01 4 S 0 956 63.84 D 34621 D Class A Common Stock 2023-03-02 4 A 0 8250 0 A 42871 D Stock Option (Right to Buy) 65.19 2023-03-02 4 A 0 20625 0 A 2033-03-02 Class A Common Stock 20625 20625 D Includes 23,750 Class A Common Stock restricted stock units that are unvested. On March 2, 2023, the Reporting Person was granted 8,250 Class A Common Stock restricted stock units, which vest in 4 equal annual installments commencing March 2, 2024. Includes 32,000 Class A Common Stock restricted stock units that are unvested. On March 2, 2023, the Reporting Person was granted 20,625 Class A Common Stock options, the options vest in 4 equal annual installments commencing March 2, 2024. /s/ Raoul Maitra, attorney-in-fact for Matthew Brown 2023-03-03