X0508 4 2024-11-05 0001701732 Altair Engineering Inc. ALTR 0001912935 Marraccini Jeffrey C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER RD. TROY MI 48083 1 See Remarks 0 Class A Common Stock 2024-11-05 4 M 0 948 0 A 5628 D Class A Common Stock 2024-11-05 4 M 0 438 0 A 6066 D Class A Common Stock 2024-11-05 4 M 0 438 0 A 6504 D Class A Common Stock 2024-11-05 4 S 0 1824 104.10 D 4680 D Stock Option (Right to Buy) 65.19 2024-11-05 4 M 0 948 0 D 2033-03-02 Class A Common Stock 948 5957 D Stock Option (Right to Buy) 50.11 2024-11-05 4 M 0 438 0 D 2032-05-11 Class A Common Stock 438 0 D Stock Option (Right to Buy) 50.11 2024-11-05 4 M 0 438 0 D 2032-05-11 Class A Common Stock 438 876 D Includes 2,825 Class A Common Stock restricted stock units that are unvested. The options vest in 4 equal annual installments commencing March 2, 2024. The options vested on May 11, 2023. This option is currently fully vested. The options vest in 3 equal annual installments commencing May 11, 2024. /s/ Raoul Maitra, attorney-in-fact for Jeffrey Marraccini 2024-11-07