X0206 3 2021-03-17 0 0001701732 Altair Engineering Inc. ALTR 0001851363 Gayle Brian C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER ROAD TROY MI 48083 0 1 0 0 Chief Accounting Officer Class A Common Stock 15649 D Stock Option (right to buy) 5.18 2027-06-09 Class A Common Stock 1417 D Stock Option (right to buy) 29.22 2030-03-16 Class A Common Stock 1091 D Stock Option (right to buy) 39.82 2030-06-02 Class A Common Stock 22500 D Stock Option (right to buy) 52.03 2030-12-02 Class A Common Stock 22500 D Stock Option (right to buy) 61.93 2031-03-15 Class A Common Stock 5443 D Includes 3,853 Class A Common Stock restricted stock units that are unvested. The options vest in 4 equal annual installments commencing on June 9, 2017. The options vest in 4 equal annual installments commencing on March 16, 2021. On June 2, 2020, the Reporting Person was granted options covering 22,500 shares of Class A Common Stock. Of such options, options covering 11,250 shares vest on June 2, 2022 and options covering 11,250 shares vest on June 2, 2023. On December 2, 2020, the Reporting Person was granted options covering 22,500 shares of Class A Common Stock. Of such options, options covering 11,250 shares vest on December 2, 2022 and options covering 11,250 shares vest on December 2, 2023. The options vest in 4 equal annual installments commencing on March 15, 2022. Exhibit List Exhibit 24 - Power of Attorney /s/ Raoul Maitra, attorney-in-fact for Brian Gayle 2021-03-18