COST vs SPY: Correlation
Measured on weekly returns over the past three years, Costco (COST) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.33, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are COST and SPY?
On 3 years of weekly data the COST/SPY correlation comes out at 0.33, moderate. The past 12 months show a weaker link (-0.02) than the 3-year average (0.33). The 5-year figure is 0.52, and annualized covariance runs at 95.0 %².
By 3-year correlation, SPY places #18 of the 33 assets tracked against COST. Their recent paths diverged sharply: over the last 12 months SPY outperformed by 21.6 percentage points (-1.0% for COST against +20.6% for SPY). Do not treat this figure as fixed: across three years the rolling one-year correlation ranged all the way from -0.03 to 0.68.
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.
COST vs SPY: side by side
| COST (Costco) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -1.0% | +20.6% |
| 5-year return | +116.3% | +82.4% |
| Volatility (ann.) | 19.8% | 14.5% |
| Beta vs S&P 500 | 0.45 | 1.00 |
| Max drawdown (3Y) | -20.7% | -18.8% |
| Market cap | $414.5B | – |
| P/E (trailing) | 48.1 | – |
| Dividend yield | 0.56% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | Consumer Staples | 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 | COST | SPY |
|---|---|---|
| 2022 | -19.0% | -18.2% |
| 2023 | +49.0% | +26.2% |
| 2024 | +39.6% | +24.9% |
| 2025 | -5.4% | +17.7% |
| 2026 | +8.9% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 0.64% of SPY is COST itself, so the fund partly moves with the stock by construction.
Are COST and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.33 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between COST and SPY?
Using weekly returns as of 2026-08-27: 0.33 over 3 years, with -0.02 over the last year and 0.52 over 5 years.
Is SPY a good diversifier for COST?
Yes, to a useful degree: a correlation of 0.33 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.33 mean?
A reading of 0.33 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: COST correlations · SPY correlations
