Darkfost2026-11-05

BTC and the S&P 500 : A decade of rising correlation

The question of the correlation between BTC and equities comes up regularly. This chart offers a few elements of an answer. Using a Z-score, we compare here the correlation between BTC’s returns and the S&P 500’s, measured over a 90-day rolling window to smooth out the noise. This comparison is based on the history since 2015, and the cumulative Z-score aggregates all the results to bring out a historical trend. Above 0, BTC is more correlated than usual; below 0, it is less correlated. The cumulative Z-score adds up these deviations over time to reveal the underlying trend. This trend has been clearly upward since the low, despite a few pullbacks. The cumulative Z-score has just moved above zero for the first time since 2015 and reaches 98.5. The figure itself matters little, but the crossing is symbolic. It means that BTC has spent more and more time moving in line with the stock market, both up and down. In the short term, the momentum is slowing. The 90-day variation falls back to +6.3% after its recent peak: the correlation remains above its average, but it is rising more slowly. This shift is probably explained by the maturing of the market. With the arrival of ETFs and easier access through exchanges, OTC desks and custody services, BTC has become far more accessible to finance professionals, who increasingly use it as a financial instrument.