Bitcoin's average one-month rolling correlation with the S&P 500 reached 0.5 across 2025, according to data compiled by Bloomberg and confirmed against independent calculations from Coin Metrics and Kaiko. The figure is up sharply from a 0.29 average across 2024 and the near-zero readings that defined much of 2023, when the asset traded for long stretches as if the broader equity tape did not exist. Against the more tech-heavy Nasdaq 100, the correlation climbed even more aggressively — to 0.52 from 0.23 the year before — meaningfully reducing the diversification benefit Bitcoin had previously offered to balanced portfolios.
The reasons are familiar but worth restating. The arrival of U.S. spot Bitcoin ETFs in January 2024 institutionalized the asset's marginal buyer base in a way that no prior product cycle managed. RIA platforms, multi-asset model portfolios, pension consultants, and macro discretionary funds now access Bitcoin through the same plumbing they use for equities, fixed income, and gold. That changes how the asset trades on a day-to-day basis. Allocators who already think in dollar-denominated terms tend to treat all liquid risk assets as a single basket, and Bitcoin has been pulled into that basket whether or not its underlying narrative supports the framing.
The mechanics show up cleanly in intraday data. A 1% move in the Nasdaq 100 in late 2025 is now associated with an average 1.4% move in BTC in the same direction, with the relationship tightening further around macro prints — CPI releases, FOMC days, large nonfarm payrolls surprises. Beta to the equity index has crept toward 1.5, against levels closer to 0.6 during the 2022-23 stretch. The pattern is most pronounced when AI-related stocks lead either direction; on those days BTC's correlation to a custom AI-exposure basket exceeds its correlation to the S&P 500 itself, suggesting the asset has effectively been absorbed into the wider AI trade.
Allocator reaction has been measured rather than alarmist. "We never sold Bitcoin to clients on the basis that it would zig when stocks zagged," one chief investment officer at a New York multi-family office said. "We sold it on the basis that it has a different long-run driver. The correlation in any given quarter is a footnote." Other research desks have been more pointed. Standard Chartered's crypto research team, in a recent note, wrote that the diversification thesis "no longer survives a quantitative review at the one-year horizon." Goldman Sachs's market strategy desk has begun including BTC alongside Russell 1000 growth and Bitcoin-mining equities as part of a single high-beta-cyclical bucket.
The broader implication is that Bitcoin's macro identity is being redrawn in real time. The asset has not stopped being scarce, programmatically issued, or globally accessible. But the buyer base that prices it on the margin has shifted from a crypto-native cohort with idiosyncratic flows to a traditional-finance cohort whose risk appetite ebbs and flows with the same factors that drive equities. The 2017 and 2021 cycles featured episodes of decoupling because the marginal price-setter was a different person from the marginal price-setter in tech stocks. In 2025, increasingly often, they are the same person.
What allocators are watching is whether the correlation regime is durable or whether a sufficiently large idiosyncratic catalyst — a serious dollar-system shock, sovereign debt event, or sustained gold breakout — is enough to break it. The closest analog so far has been the brief 2024 decoupling around the ETF launch, which proved transient. Most desks are now modeling Bitcoin into 2026 with an assumed 0.4 to 0.6 correlation to risk assets and treating any further compression toward zero as the surprise outcome rather than the base case.