FSLY vs SPY: Correlation
Fastly, Inc. (FSLY) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.18.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are FSLY and SPY?
Across a 3-year window, the weekly returns of FSLY and SPY correlate at 0.18, weak. The link has loosened recently: the 1-year correlation (-0.16) runs below the 3-year figure (0.18). Stretching to 5 years gives 0.30, with an annualized covariance of 264.2 %².
Among the 11 assets we track against FSLY, SPY ranks #6 by 3-year correlation. The last year tells two different stories: FSLY led by 208.4 percentage points, +229.0% for FSLY against +20.6% for SPY. Risk is not evenly split, since FSLY carries 7.0 times the volatility of the other side.
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.
FSLY vs SPY: side by side
| FSLY (Fastly, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +229.0% | +20.6% |
| 5-year return | -43.5% | +82.4% |
| Volatility (ann.) | 101.8% | 14.5% |
| Beta vs S&P 500 | 1.26 | 1.00 |
| Max drawdown (3Y) | -80.0% | -18.8% |
| Market cap | $3.9B | – |
| 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 | FSLY | SPY |
|---|---|---|
| 2022 | -76.9% | -18.2% |
| 2023 | +117.3% | +26.2% |
| 2024 | -47.0% | +24.9% |
| 2025 | +7.8% | +17.7% |
| 2026 | +142.0% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are FSLY and SPY good diversifiers for each other?
By historical standards, yes. A correlation of 0.18 means the two rarely move for the same reasons.
FAQ
What is the correlation between FSLY and SPY?
The FSLY/SPY correlation stands at 0.18 on a 3-year window (1 year: -0.16, 5 years: 0.30), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for FSLY?
By historical standards, yes. A correlation of 0.18 means the two rarely move for the same reasons.
What does a correlation of 0.18 mean?
A reading of 0.18 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: FSLY correlations · SPY correlations
