SCHEDULE 13G/A

ALTAIR ENGR INC

Class A Common Stock, $0.0001 par value per share · CUSIP: 021369103

Event date: 2025-03-31

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Matrix Capital Management Company, LP

  Shares: 0.00 · Class: 0%

• David E. Goel

  Shares: 0.00 · Class: 0%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.