BFLY vs SPY: Correlation
Measured on weekly returns over the past three years, Butterfly Network, Inc. (BFLY) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.34, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BFLY and SPY?
Across a 3-year window, the weekly returns of BFLY and SPY correlate at 0.34, moderate. The link has loosened recently: the 1-year correlation (0.24) runs below the 3-year figure (0.34). Stretching to 5 years gives 0.42, with an annualized covariance of 484.6 %².
Among the 11 assets we track against BFLY, SPY sits near the bottom by co-movement, at rank #7. Correlation aside, the last 12 months split them widely, with BFLY ahead by 434.8 points (+455.4% versus +20.6%). Note the risk asymmetry: BFLY runs 6.8 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 SPY: side by side
| BFLY (Butterfly Network, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +455.4% | +20.6% |
| 5-year return | -27.5% | +82.4% |
| Volatility (ann.) | 98.1% | 14.5% |
| Beta vs S&P 500 | 2.32 | 1.00 |
| Max drawdown (3Y) | -72.4% | -18.8% |
| Market cap | $2.3B | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | US Listed | ETF · US Large Cap |
SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | BFLY | SPY |
|---|---|---|
| 2022 | -63.2% | -18.2% |
| 2023 | -56.1% | +26.2% |
| 2024 | +188.9% | +24.9% |
| 2025 | +21.8% | +17.7% |
| 2026 | +129.5% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BFLY and SPY good diversifiers for each other?
A fair diversifier. At 0.34, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between BFLY and SPY?
Using weekly returns as of 2026-08-27: 0.34 over 3 years, with 0.24 over the last year and 0.42 over 5 years.
Is SPY a good diversifier for BFLY?
A fair diversifier. At 0.34, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.34 mean?
Correlation ranges from −1 to +1. Values near +1 mean two assets move together, near 0 that they move independently, and negative values that they tend to move in opposite directions. It measures co-movement, not performance.
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Related comparisons
Hubs: BFLY correlations · SPY correlations
