Reddit officially joined the S&P 500 index on Tuesday, replacing AvalonBay Communities as the apartment REIT merges with Equity Residential. The announcement sent Reddit shares surging more than 12% on the Friday before inclusion, closing at $178.09 as investors positioned ahead of forced buying from index funds that must now hold the stock to track the benchmark.
JPMorgan estimates the inclusion creates demand for roughly 16.7 million Reddit shares, worth close to $3 billion at Friday’s closing price. That figure represents about 8.1% of Reddit’s fully diluted share count and is nearly three times the stock’s average daily trading volume since its 2024 IPO. Because that much buying has to land in a short window, JPMorgan flagged the potential for real market depth issues on inclusion day itself — meaning short-term price swings could be sharper than usual as index funds compete for shares. Despite the pop, Reddit stock remains down more than 30% year-to-date and over 40% off its all-time high from September 2025, underscoring how volatile the name has been even as its business has grown.
For retail investors, S&P 500 inclusion is a double-edged event. The immediate mechanical buying can create a short-term price floor, but that demand is temporary — once index funds finish their rebalancing, the artificial support disappears and the stock trades on fundamentals again. Anyone holding Reddit heading into this week should expect elevated volatility around the actual inclusion date rather than assuming the rally continues indefinitely. Those without a position should watch how the stock behaves once the index-driven buying pressure fades before deciding whether the underlying growth story justifies a new entry.
