AP reports Reddit will enter the S&P 500 on Aug. 18.
Why it matters: S&P 500 inclusion can trigger automatic buying from index funds that track the benchmark. It also boosts visibility for a widely watched public tech company.
- S&P Dow Jones Indices said Reddit will be added to the S&P 500 before the open on Tuesday, Aug. 18, 2026.
- Index-tracking mutual funds and ETFs that follow the S&P 500 will need to buy Reddit shares to replicate the benchmark.
- Reddit stock jumped nearly 14% intraday on Friday, Aug. 14, after the inclusion news.
- S&P says the index covers about 80% of available U.S. market capitalization.
Reddit will join the S&P 500 next week, a move that gives the online forum a boost in prestige and, more importantly for markets, a new class of forced buyers. AP reported the addition on Friday, citing S&P Dow Jones Indices, with the change effective before the open on Tuesday, Aug. 18, 2026. AP's report
The S&P 500 is widely viewed as the best single gauge of large-cap U.S. equities and is designed to be representative and investable for the U.S. market. S&P says the index includes 500 leading companies and covers about 80% of available U.S. market capitalization. S&P 500 index description
That matters because mutual funds and ETFs that track the benchmark need to own the stocks in it. Reddit's addition should therefore create incremental demand from passive and benchmarked investors, even though the company itself is not changing its business model.
The stock market reacted immediately. Reddit shares rose nearly 14% intraday on Aug. 14 after the inclusion news. S&P Dow Jones Indices recently said it would not loosen its seasoning, financial viability, or minimum investable weight factor rules solely because of market capitalization. S&P consultation results
By the numbers
- 14% - Reddit stock's intraday rise on Aug. 14 after the inclusion news.
- 80% - Approximate share of available U.S. market capitalization covered by the S&P 500.
- 500 - Number of leading U.S. companies in the benchmark.
Yes, but: The move is a benchmark mechanics story, not a change to Reddit's underlying business.
What's next: Reddit's addition becomes effective before the market open on Tuesday, Aug. 18, 2026.