ビットコイン vs 米国株の相関性

Pearson correlation of log daily returns between Bitcoin and the S&P 500 (^GSPC) over shared trading days, in 30-day and 90-day rolling windows.

Pre-2020 BTC was nearly uncorrelated with equities; after institutions entered in 2020 the correlation regime shifted up, with the 90d reading topping 0.6 during the 2022 liquidity tightening — BTC trading as a high-beta risk asset. A fall back toward zero usually means crypto-native drivers have retaken the wheel.