X0306 4/A 2017-11-03 2017-11-03 0 0001701732 Altair Engineering Inc. ALTR 0001720809 Christ Revocable Trust C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER ROAD TROY MI 48083 0 0 1 0 Class A Common Stock 2017-11-03 4 C 0 800000 0.00 A 800000 D Class A Common Stock 2017-11-03 4 S 0 800000 12.09 D 0 D Class B Common Stock 0.00 2017-11-03 4 C 0 800000 0.00 D Class A Common Stock 800000 8546728 D This amendment is being filed to correct the number of shares converted and sold. The number of shares converted and sold was misstated on reporting person's original Form 4 filed with the Securities and Exchange Commission on November 3, 2017. These shares were sold by the reporting person as a selling stockholder pursuant to an underwritten public offering by the Issuer. The offering closed on November 3, 2017. The reported sale price reflects the price at which the reporting person sold shares to the underwriters. Each share of Class B common stock is immediately convertible, at the option of the shareholder, into one share of Class A common stock and shall automatically convert into Class A common stock upon the occurrence of certain events. Please see Altair Engineering Inc. Registration Statement filed with the Securities and Exchange Commission on Form S-1 (File No. 333-220710) for a description of the conversion rights. Exhibit List /s/ Raoul Maitra attorney-in-fact for Christ Revocable Trust dated May 8, 2015 2018-06-11