Robinhood and AppLovin Added to S&P 500, Stocks Surge in After-Hours Trading

Robinhood Markets Inc. and AppLovin Corp. will join the S&P 500 index, replacing Caesars Entertainment Inc. and MarketAxess Holdings Inc. respectively. The announcement from S&P Global's index committee triggered a 7% surge in Robinhood's stock during after-hours trading, while AppLovin also saw significant gains.

This quarterly rebalancing forces index-tracking funds to mechanically buy the new constituents, creating predictable upward pressure. The inclusion marks a turnaround for both companies—Robinhood had been snubbed in June's rebalancing, while AppLovin faced short-seller opposition earlier this year.

The commission-free trading platform, known for its role in the meme stock frenzy, now gains institutional validation through S&P 500 inclusion. MarketAxess and Caesars Entertainment will MOVE to the S&P MidCap 400 index effective prior to the September 20 opening bell.