LRN, FTDR, ORA, SNCY jump on S&P index changes

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A rack of acquisitions is spurring change in the S&P small-cap and mid-cap indexes.

Stride (NYSE:LRN) is up 9% after hours as it's moving into the S&P SmallCap 600. It's headed there to replace Omnicell (OMCL), which itself is moving up to the S&P MidCap400 to take the place of Coherent (COHR), set to be acquired by II-VI. That index move is effective prior to the open of trading on Tuesday, July 5.

Frontdoor (NASDAQ:FTDR) is up 10.8% in late trading as it's moving into the SmallCap 600 to take the place of Southwestern Energy (SWN) - which is down 2% postmarket as it heads up to the MidCap 400. There Southwestern Energy will take the place of CDK Global (CDK), set to be acquired by Brookfield Business Partners. Those index moves are set for before the open on July 6.

Ormat Technologies (NYSE:ORA) is up 7.2% after hours as it's moving into the MidCap 400 before the open on July 7; it's taking the place of CMC Materials (CCMP), set to be acquired by Entegris.

Loyalty Ventures (LYLT) has slid 3.8% postmarket as it's getting bumped from the SmallCap 600 before the open on July 5. It's making room for Enhabit (EHAB), which is spinning off from Encompass Health (EHC), and Loyalty Ventures is considered no longer representative of small caps.

Finally, Sun Country Airlines Holdings (NASDAQ:SNCY) has jumped 8.6% postmarket as it's moving into the SmallCap 600 before the open on July 5. It's replacing Neenah (NP), set to be acquired by Schweitzer-Mauduit International.