144 0001720314 XXXXXXXX LIVE 0001701732 Altair Engineering, Inc. 001-38263 1820 E. Beaver Road Troy MI 48083 248-614-2400 James Ralph Scapa CEO Class A Common J.P. Morgan Securities LLC

390 Madison Avenue 6th Floor New York NY 10017

30000 2245800 53414224 07/17/2023 Nasdaq Class A Common 11/01/2017 Direct Investment by the James R. Scapa Declaration of Trust dated 03/05/87 Issuer N 15000 11/01/2017 N/A Class A Common 11/01/2017 Direct Investment by the JRS Investment LLC Issuer N 15000 11/01/2017 N/A N James Scapa Declaration of Trust, JRS Investments LLC

Care of Altair Engineering 1820 E. Beaver Road Troy MI 48083

Class A Common 05/16/2023 10000 679432 James Scapa Declaration of Trust, JRS Investments LLC

Care of Altair Engineering 1820 E. Beaver Road Troy MI 48083

Class A Common 06/16/2023 10000 751755 Of the 30,000 shares being filed, 15,000 shares will be sold by the James R. Scapa Declaration of Trust dated 03/05/87, James R. Scapa as Trustee and 15,000 shares will be sold by the JRS Investment LLC, James R. Scapa as Manager 07/17/2023 12/14/2022 /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for James Ralph Scapa