X0306 4 2019-05-02 0 0001701732 Altair Engineering Inc. ALTR 0001720314 Scapa James Ralph C/O ALTAIR ENGINEERING INC. 1820 E. BIG BEAVER ROAD TROY MI 48083 1 1 1 0 Chief Executive Officer Class A Common Stock 2019-05-02 4 C 0 12685 0.00 A 12685 I By James R. Scapa Declaration of Trust dated March 5, 1987 Class A Common Stock 2019-05-02 4 S 0 12685 36.89 D 0 I By James R. Scapa Declaration of Trust dated March 5, 1987 Class A Common Stock 2019-05-02 4 C 0 4059 0.00 A 4059 I By JRS Investments, LLC Class A Common Stock 2019-05-02 4 S 0 4059 36.88 D 0 I By JRS Investments, LLC Class A Common Stock 40000 D Class B Common Stock 0.00 2019-05-02 4 C 0 12685 0.00 D Class A Common Stock 12685 11593117 I By James R. Scapa Declaration of Trust dated March 5, 1987 Class B Common Stock 0.00 2019-05-02 4 C 0 4059 0.00 D Class A Common Stock 4059 7305033 I By JRS Investments, LLC Reporting person serves as Trustee. Reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose. 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 5, 2019. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.52 to $37.41 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. Reporting person serves as Manager. Reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.58 to $37.41 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 35,000 Class A Common Stock restricted stock units that are unvested. 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. 333-225412) for a description of the conversion rights. /s/ Raoul Maitra, attorney-in-fact for James R. Scapa 2019-05-06