X0306 4 2022-02-15 0001701732 Altair Engineering Inc. ALTR 0001720642 Dias Nelson C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER RD. TROY MI 48083 1 Chief Revenue Officer Class A Common Stock 2022-02-15 4 A 0 3800 0 A 30529 D Class A Common Stock 2022-03-15 4 S 0 8 59.48 D 30521 D Stock Option (Right to Buy) 61.79 2022-02-15 4 A 0 11375 0 A 2032-02-15 Class A Common Stock 11375 11375 D On February 15, 2022, the Reporting Person was granted 3,800 Class A Common Stock restricted stock units, which vest in 4 equal annual installments commencing February 15, 2023. Includes 7,615 Class A Common Stock restricted stock units that are unvested. This also includes 109 shares of Class A Common Stock purchased under the Altair Engineering Inc. 2021 Employee Stock Purchase Plan in a transaction exempt under Rule 16b-3(c). Includes 6,567 Class A Common Stock restricted stock units that are unvested. On February 15, 2022, the Reporting Person was granted 11,375 Class A Common Stock options, the options vest in 4 equal annual installments commencing February 15, 2023. /s/ Raoul Maitra, attorney-in-fact for Nelson Navin Patrick Dias 2022-03-16