Is Bitcoin Trading Like the Nasdaq Again? The 30-Day Correlation Has Jumped From 0.15 to 0.60 Since August — the 80th Percentile of 1,223 Windows Since 2021 — Yet the 60-Day Reading Is Only 0.35

When the Nasdaq lost 5.3% in eight sessions this month, the question on every crypto desk was whether bitcoin was just a leveraged tech stock again. The short answer from the data is: lately, more than it was in the summer, but not by as much as the loudest headlines suggest. Over the 30 trading days from 8 September to 19 October 2026, the correlation between bitcoin’s daily returns and the Nasdaq Composite’s was 0.60. On 31 August the same measure was 0.15. Over the 60 trading days to 19 October it is only 0.35, which means the earlier half of that window had almost no relationship at all.

Correlation here means the standard Pearson coefficient of daily percentage returns: +1 would mean the two assets always move the same way in proportion, 0 means no linear relationship, and −1 means they always move opposite. It says nothing about direction or size on its own, and it is unstable over short windows, which is exactly why we show several.

The numbers

Two things stand out. First, 0.60 is high relative to history but it is not exceptional: 19.5% of all 30-day windows since 2021 were at or above 0.60, and the highest readings, around 0.82, came in May 2022 during the last big growth-stock selloff. Second, the gap between the 30- and 60-day numbers shows how fast the relationship can switch on: roughly half the 60-day window (from late July to early September) had a near-zero or weak link, and then the October selloff added a run of days when both fell together.

How the last eight sessions lined up

Seven of the eight sessions had the same sign for both assets; the exception was 13 October. On 16 October, the worst of the stock selloff, bitcoin fell 0.78% while the Nasdaq fell 2.15%: the direction matched, but bitcoin’s move was far smaller. That is the pattern a correlation of 0.60 hides: it measures whether the two move together, not how much.

Which stocks does bitcoin really track?

The company-level numbers are more striking than the index ones. Over the last 252 trading days, bitcoin’s daily returns have a correlation of 0.81 with Strategy (MSTR), whose business is holding bitcoin, and 0.37 with Tesla, which holds 11,509 bitcoin but is valued mostly on cars, energy and AI. Over the last 60 days the figures are 0.80 and 0.41. In other words, a company is not a bitcoin proxy simply because it owns coins: the more the share price is about something else, the weaker the link. That matters on a day when SpaceX, with 18,712 bitcoin and a $14.6 billion revenue quarter, is the market’s focus; see our earnings news piece.

Does it matter when the link is high?

One tempting reading is that a high correlation is a warning. We tested a narrow version. Across 1,213 trading days with a 10-day forward window, bitcoin’s average 10-day return was +0.95% (median +0.43%). On the 351 days when the 30-day correlation was 0.55 or higher, the average was −0.17% (median −0.63%). That looks like a pattern, but it is weak evidence: the windows overlap heavily, so they are not 351 independent observations, the 0.55 threshold was chosen after looking at the data, and we did not test which episodes drive the result. We report it for completeness and do not treat it as a signal.

A separate asymmetry is easier to defend because it uses all the data. Over the last 252 sessions, when the Nasdaq rose (135 days) bitcoin averaged +0.82% and was up on 81 of them (60%); when the Nasdaq fell (117 days) bitcoin averaged −1.11% and was up on only 36 (31%). On down days for stocks, bitcoin has tended to fall more than it rose on up days: it has taken more of the downside than the upside, which is consistent with the beta of 1.31.

Year by year

The 2022 reading, when both assets were driven by interest-rate expectations, was the highest; 2023, when bitcoin recovered on its own narrative, was the lowest. The 2026 figure of 0.45 is in line with 2025 and sits between the extremes. Nothing in the annual data says the current 30-day number is a regime change; the daily data say it is a recent tightening during a stress episode.

Why correlation rises in selloffs

A common explanation is that in a sharp equity drawdown, investors sell what they can sell and margin calls hit leveraged books across assets, so different positions move together; bitcoin trades around the clock, so it often absorbs the first reaction. Our VIX analysis found that on the 26 days the VIX jumped 10% or more, bitcoin averaged −2.70%, and our semiconductor-ETF test found a −1.07% average on days that fund fell 2% or more. Both fit the idea that bitcoin shares the pain of risk-off days. They are descriptions of one year of data, not guarantees, and the opposite is also true: on 13 October bitcoin rose 1.63% as the Nasdaq slipped 0.15%.

What to watch this week

• Wednesday 21 October, after the close: Tesla and Meta report. A big move in either could reset the Nasdaq’s direction, and with it this correlation.
• 27–28 October: the FOMC meeting. In our 38-meeting study bitcoin’s average on decision days was +0.49%, with a standard error of 0.51 points, which is statistically indistinguishable from zero.
• 29 October: the PCE inflation report.

How to use this: treat the 30-day correlation as a gauge of how much stock-market news is currently driving bitcoin, not as a trade. Recompute it when the window rolls forward; if the Nasdaq calms and the reading falls back toward the median of 0.45, the AI-selloff story has lost its grip. If it climbs toward 0.8, the 2022 pattern is returning.

Method and limits. Daily closes for BTC-USD, the Nasdaq Composite (^IXIC), Strategy (MSTR) and Tesla (TSLA) come from Yahoo Finance (example page). We matched dates present in both series (1,252 daily returns, 22 October 2021 to 19 October 2026) and computed each return from the previous US trading day, so a Monday bitcoin return covers the weekend. Yahoo’s BTC series had no 20 October close at pull time, so the sample ends on 19 October. Rolling windows overlap and are strongly autocorrelated; percentiles are therefore descriptive. The 0.55 threshold and the 10-day horizon were chosen after looking at the data. Bitcoin’s daily close is at 00:00 UTC while US stocks close at 20:00–21:00 UTC, so a few hours of non-overlap are built into every pair.

Method: bitcoin prices, highs, lows and closes are Coinbase Exchange candles (UTC day or UTC hour) pulled by Bitcoin Mastery at about 06:15 UTC on Wednesday 21 October 2026; the 21 October candle is still open at that time, so any closing figure quoted is the 20 October close unless stated. Index, stock, VIX, oil and yield figures are Yahoo Finance daily data (US closes of Tuesday 20 October) or the news sources cited. Other third-party figures are attributed to their source and date. All correlations, betas, percentiles and forward returns above are our own calculations.

Disclaimer: This article is for informational purposes only and does not constitute investment advice. Bitcoin and other cryptocurrencies are volatile and you can lose some or all of the money you put in. Nothing here is a recommendation to buy, sell or hold bitcoin, any exchange-traded fund, any listed security or any other asset, and the technical levels, probabilities and scenarios discussed are descriptions of published data, not forecasts. Do your own research and consult a licensed financial advisor before making investment decisions.