X0306 4 2019-04-15 0 0001701732 Altair Engineering Inc. ALTR 0001720645 Nichols Martin E C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER ROAD TROY MI 48083 0 1 0 0 Chief Information Officer Class A Common Stock 2019-04-15 4 S 0 2500 36.311 D 79415 D The sale of the shares of Class A Common Stock were made pursuant to a plan intended to comply with Rule 10b5-1 of the Exchange Act, previously entered into on March 12, 2019. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.07 to $36.49 per share, inclusive. The reporting person undertakes to provide to Altair Engineering Inc., any security holder of Altair Engineering Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth herein. Includes 4,098 Class A Common Stock restricted stock units that are unvested. /s/ Raoul Maitra, attorney-in-fact for Martin E. Nichols 2019-04-17