Apple and Nvidia now make up 15% of the S&P 500—a concentration level that's raising eyebrows about systemic risk.

The argument: When equity markets become this top-heavy, diversification suffers. A handful of mega-cap tech names drive the entire index, meaning your 401(k) and index funds are increasingly tied to the same few stocks.

The $BTC case: Some investors see this as a reason to hold assets outside traditional equity and banking systems—something uncorrelated to the same liquidity machine that props up the S&P.