MSCI has proposed a rule that may exclude companies with over 50% of their holdings in cryptocurrencies from its major indexes. This change could lead to a significant sell-off, estimated between $10 billion and $15 billion. The proposal, which is open for public feedback until January 2026, could affect investment strategies in the crypto sector and broader market dynamics. Companies like MicroStrategy, which holds 660,000 BTC, are at risk of being removed from these indexes if the rule is implemented. Critics argue that the 50% threshold does not consider the operational realities of such firms and could lead to increased market volatility.