An analysis has found that Bitcoin has become more likely to move in the same direction as the U.S. stock market.

CoinPost, a blockchain news outlet, reported on Nov. 6 that Darkfost, an analyst at on-chain analytics firm CryptoQuant, said a long-term correlation gauge between Bitcoin and the S&P 500 has crossed above the zero line for the first time since 2015.

The gauge calculates the correlation of returns between the two assets using a 90-day moving average, standardises it as a Z-score and then accumulates the value from 2015. A positive Z-score means correlation is higher than average, while a negative score means it is lower. Crossing above zero in the accumulated value does not mean the correlation coefficient itself has turned positive for the first time. It shows that long-running changes in correlation have tilted toward stronger co-movement.

More recently, the pace of co-movement has slowed somewhat. The 90-day rate of change in the gauge fell from a recent peak and recorded plus 6.3 percent. The long-term trend of co-movement continues, but its speed has eased.

Darkfost cited market maturation as a main driver of the shift. He said the introduction of spot Bitcoin exchange-traded funds and the expansion of over-the-counter desks and custody services have improved institutional investors' access to the market. He also saw broader moves to treat Bitcoin as a financial product and include it in portfolios.

A strengthening long-term correlation does not rule out short-term price divergence. Darkfost previously noted that in April, the period of weak correlation between Bitcoin and the S&P 500 lasted the longest since 2020. That means the two assets can move in different directions in certain periods, even as linkage may increase on a 10-year horizon.

The two markets also weakened side by side during a recent sell-off. U.S. stocks fell on Nov. 5, led by artificial intelligence and semiconductor-related shares. The S&P 500 fell 4.36 percent from the previous day and the Nasdaq Composite dropped 5.52 percent. The decline was reported to have been driven by prospects of tighter oversight of AI data centres and concerns about the profitability of AI investments after Democrats secured control of Congress in the midterm elections.

Bitcoin also fell with equities. Bitcoin briefly regained the $80,000 level last week, but later gave back midterm-election gains and slipped below $75,000. Shares of Coinbase and Strategy, which are tied to cryptocurrencies, also fell about 10 percent each.

Liquidations of leveraged positions also rose quickly. Coinglass data showed about $1.08 billion in positions were liquidated over 24 hours on Nov. 5. As Bitcoin's linkage to the stock market structurally increases, the possibility that short-term price swings will become more sensitive to the direction of U.S. stocks is emerging as a focus for market watchers.