According to @EricBalchunas, MicroStrategy ($MSTR) was not admitted to the S&P 500 despite meeting criteria because the S&P Index Committee declined the addition (source: Eric Balchunas on X, Sep 5, 2025). The S&P Dow Jones Indices methodology confirms the S&P 500 is selected by a committee with discretion to deviate from mechanical rules, effectively making SPX an actively chosen basket within stated guidelines (source: S&P Dow Jones Indices, S&P U.S. Indices Methodology). Without inclusion, S&P 500 index-tracking funds will not purchase MSTR as part of routine rebalancing, limiting automatic passive inflows relative to an inclusion scenario (source: SPDR S&P 500 ETF Trust SPY, iShares Core S&P 500 ETF IVV, and Vanguard S&P 500 ETF VOO prospectuses). S&P Dow Jones Indices notes that trillions of dollars are indexed or benchmarked to the S&P 500, so committee decisions can materially influence demand and liquidity for would-be constituents (source: S&P Dow Jones Indices, S&P 500 benchmarked assets disclosures). Given MicroStrategy states it holds bitcoin as a primary treasury reserve asset, traders often treat MSTR as a high-beta proxy for BTC; exclusion means SPX-linked passive portfolios will not gain that direct BTC-sensitive exposure via MSTR (source: MicroStrategy Form 10-K and investor relations; S&P Dow Jones Indices methodology).

According to @KookCapitalLLC, social posts claim MicroStrategy (MSTR) will be added to the S&P 500 this Friday, while the author notes MSTR is eligible but questions whether the Index Committee will actually add it. According to S&P Dow Jones Indices methodology, meeting eligibility criteria does not guarantee inclusion and membership changes are decided by the Index Committee, typically announced after the U.S. market close on the first Friday of March, June, September, and December via official press release. According to S&P Dow Jones Indices implementation guidelines, confirmed additions generally prompt passive index and closet-index fund buying at the effective date, creating execution and liquidity impacts that active traders monitor. According to MicroStrategy investor relations and SEC filings, MSTR’s equity is highly sensitive to the company’s Bitcoin (BTC) holdings, meaning any inclusion-driven flows could intersect with BTC-linked volatility.