Reddit Wins S&P 500 Seat Ahead of Aug. 18 Trading, Sparks Rally

Reddit will join the S&P 500 next week in an off-cycle change by S&P Dow Jones Indices, replacing AvalonBay Communities as Equity Residential acquires it; the inclusion takes effect before trading starts on Aug. 18 and sparked a more-than-10% after‑hours rally for Reddit. The company, which went public in 2024, has grown its ad‑tech business and struck AI partnerships with OpenAI and Google, posting its eighth consecutive quarter of over 60% revenue growth in July, though shares remain down year‑to‑date.