144 0001805096 XXXXXXXX LIVE 0001701732 Altair Engineering Inc. 001-38263 1820 E. BIG BEAVER ROAD TROY MI 48083 248-614-2400 Saravia Gilma Officer Class A Common Stock Morgan Stanley Smith Barney LLC

Harborside 2 200 Hudson Street, Suite 501 Jersey City NJ 07311

263 29350.80 60401224 03/03/2025 NASDAQ Class A Common Stock 03/02/2025 Class A Common Stock Restricted Stock Unit Vesting Issuer N 917 03/02/2025 N/A N Gilma Saravia

1820 E. Big Beaver Rd. Troy MI 48083

Class A Common Stock 02/26/2025 243 27101.79 Represents registered Class A common stock to be sold pursuant to the Issuer's 2017 Equity Incentive Plan for sell-to-cover transactions for tax withholding obligations resulting from the vesting of Class A common stock restricted stock units. Such sale was previously reported on a Form 4. 03/03/2025 Gilma Saravia