Atmus Filtration Joins S&P SmallCap 600

Atmus Filtration Technologies shares rose 4.6% in after‑hours trading after announcement of inclusion in the S&P SmallCap 600 index.
The company will replace Air Lease Corp in the index, effective before the market opens on Thursday, April 9, 2026.
Both firms belong to the Industrials sector, and the change follows Sumitomo Corporation’s pending acquisition of Air Lease Corp.
Index additions typically boost stocks as passive funds must buy the newly added shares.