SPY vs STAA: Correlation
How closely do SPDR S&P 500 ETF Trust (SPY) and STAAR Surgical Company (STAA) trade together? Their weekly returns over three years give a correlation of 0.21, which is weak.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPY and STAA?
On 3 years of weekly data the SPY/STAA correlation comes out at 0.21, weak. Recent behaviour matches the longer record: 0.21 over 1 year against 0.21 over 3. The 5-year figure is 0.40, and annualized covariance runs at 188.8 %².
By 3-year correlation, STAA places #3185 of the 4755 assets tracked against SPY. Their recent paths diverged sharply: over the last 12 months SPY outperformed by 39.2 percentage points (+20.6% for SPY against -18.6% for STAA). Risk is not evenly split, since STAA carries 4.3 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.
SPY vs STAA: side by side
| SPY (SPDR S&P 500 ETF Trust) | STAA (STAAR Surgical Company) | |
|---|---|---|
| 1-year return | +20.6% | -18.6% |
| 5-year return | +82.4% | -85.0% |
| Volatility (ann.) | 14.5% | 61.9% |
| Beta vs S&P 500 | 1.00 | 0.90 |
| Max drawdown (3Y) | -18.8% | -71.1% |
| Market cap | – | $1.1B |
| P/E (trailing) | – | 279.9 |
| Dividend yield | 1.01% | 0.00% |
| Expense ratio | 0.09% | – |
| Assets under management | $795.3B | – |
| Sector / category | ETF · US Large Cap | US Listed |
SPY, State Street Investment Management's Large Blend fund, carries $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | SPY | STAA |
|---|---|---|
| 2022 | -18.2% | -46.8% |
| 2023 | +26.2% | -35.7% |
| 2024 | +24.9% | -22.2% |
| 2025 | +17.7% | -4.9% |
| 2026 | +13.7% | -3.0% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are SPY and STAA good diversifiers for each other?
A fair diversifier. At 0.21, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between SPY and STAA?
As of 2026-08-27, the correlation of weekly returns between SPY and STAA is 0.21 over 3 years, 0.21 over 1 year and 0.40 over 5 years.
Is STAA a good diversifier for SPY?
A fair diversifier. At 0.21, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.21 mean?
On the −1 to +1 scale, 0.21 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.
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Related comparisons
Hubs: SPY correlations · STAA correlations
