BFLY vs XBI: Correlation
How closely do Butterfly Network, Inc. (BFLY) and SPDR S&P Biotech ETF (XBI) trade together? Their weekly returns over three years give a correlation of 0.46, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BFLY and XBI?
Across a 3-year window, the weekly returns of BFLY and XBI correlate at 0.46, moderate. Little has changed lately, as the 1-year reading of 0.42 lands near the 3-year figure. Stretching to 5 years gives 0.56, with an annualized covariance of 1238.8 %².
XBI is one of the assets that tracks BFLY most closely: it ranks #3 out of the 11 assets we track against BFLY. Correlation aside, the last 12 months split them widely, with BFLY ahead by 368.2 points (+455.4% versus +87.2%). Note the risk asymmetry: BFLY runs 3.5 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
How is this computed?
Pearson correlation on weekly returns: ρ(A,B) = cov(rA, rB) / (σA · σB), over windows of 52, 156 and 260 weeks. Covariance is annualized (×52) and expressed in %². Full definitions on the methodology page.
BFLY vs XBI: side by side
| BFLY (Butterfly Network, Inc.) | XBI (SPDR S&P Biotech ETF) | |
|---|---|---|
| 1-year return | +455.4% | +87.2% |
| 5-year return | -27.5% | +28.6% |
| Volatility (ann.) | 98.1% | 27.7% |
| Beta vs S&P 500 | 2.32 | 1.09 |
| Max drawdown (3Y) | -72.4% | -33.0% |
| Market cap | $2.3B | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | – |
| Sector / category | US Listed | ETF · Thematic |
Year-by-year returns
| Year | BFLY | XBI |
|---|---|---|
| 2022 | -63.2% | -25.9% |
| 2023 | -56.1% | +7.6% |
| 2024 | +188.9% | +1.0% |
| 2025 | +21.8% | +35.9% |
| 2026 | +129.5% | +38.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BFLY and XBI good diversifiers for each other?
A fair diversifier. At 0.46, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between BFLY and XBI?
The BFLY/XBI correlation stands at 0.46 on a 3-year window (1 year: 0.42, 5 years: 0.56), computed from weekly returns as of 2026-08-27.
Is XBI a good diversifier for BFLY?
A fair diversifier. At 0.46, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.46 mean?
On the −1 to +1 scale, 0.46 describes how much the two returns move together: +1 is lockstep, 0 is independence, negative values mean opposite directions. It says nothing about which performed better.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/bfly-vs-xbi.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/bfly-vs-xbi/)
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Related comparisons
Hubs: BFLY correlations · XBI correlations
