Reddit will be added to the S&P 500 on August 18 in an off-cycle change, S&P Dow Jones Indices announced Thursday. The social networking platform's shares surged 11% in after-hours trading following the news.
Reddit replaces AvalonBay Communities, a real estate investment trust being acquired, in the benchmark index. Off-cycle additions to the S&P 500 are uncommon; the index typically reconstitutes quarterly. Reddit went public in March 2024 at a valuation near $61 billion.
The S&P 500 includes roughly 500 of the largest U.S. publicly traded companies by market capitalization. Inclusion typically drives inflows from passive funds tracking the index, as money managers must hold the stock to match their benchmark weights. The effective date gives institutional investors five days to adjust holdings.
Reddit has grown its user base to more than 430 million monthly active users across its platform of community forums, according to recent disclosures. The company turned profitable in the first quarter of 2024 after years of losses. Revenue in the second quarter of 2026 reached $348 million, up 54% year-over-year, according to the company's earnings report.
An off-cycle addition occurs when a company meets the index's inclusion criteria outside the regular quarterly review process. Reddit's addition within five days of the announcement is unusually swift.
Reddit's stock has risen from its March 2024 IPO price of $34 per share. The 11% surge on Thursday alone added roughly $2.2 billion to its market value, assuming a stock price of roughly $120 at the time of the announcement. Any fund tracking the S&P 500 must now hold Reddit in proportion to its market weight.
