COST vs QUAL: Correlation
Measured on weekly returns over the past three years, Costco (COST) and iShares MSCI USA Quality Factor ETF (QUAL) carry a correlation of 0.41, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are COST and QUAL?
On 3 years of weekly data the COST/QUAL correlation comes out at 0.41, moderate. The past 12 months show a weaker link (0.10) than the 3-year average (0.41). The 5-year figure is 0.57, and annualized covariance runs at 112.2 %².
By 3-year correlation, QUAL places #5 of the 33 assets tracked against COST. Their recent paths diverged sharply: over the last 12 months QUAL outperformed by 20.7 percentage points (-1.0% for COST against +19.7% for QUAL). The relationship is regime-dependent: the rolling one-year correlation swung between 0.09 and 0.69 over the past three years, so this pair behaves very differently depending on the market environment.
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 QUAL: side by side
| COST (Costco) | QUAL (iShares MSCI USA Quality Factor ETF) | |
|---|---|---|
| 1-year return | -1.0% | +19.7% |
| 5-year return | +116.3% | +68.0% |
| Volatility (ann.) | 19.8% | 14.0% |
| Beta vs S&P 500 | 0.45 | 0.93 |
| Max drawdown (3Y) | -20.7% | -18.0% |
| Market cap | $414.5B | – |
| P/E (trailing) | 48.1 | – |
| Dividend yield | 0.56% | 0.86% |
| Expense ratio | – | 0.15% |
| Assets under management | – | $46.5B |
| Sector / category | Consumer Staples | ETF · US Style |
QUAL, iShares's Large Blend fund, carries $46.5B under management, 123 holdings, a 0.15% expense ratio, a 0.86% trailing dividend yield.
Year-by-year returns
| Year | COST | QUAL |
|---|---|---|
| 2022 | -19.0% | -20.5% |
| 2023 | +49.0% | +30.9% |
| 2024 | +39.6% | +22.3% |
| 2025 | -5.4% | +12.7% |
| 2026 | +8.9% | +13.5% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 1.09% of QUAL is COST itself, so the fund partly moves with the stock by construction.
Are COST and QUAL good diversifiers for each other?
A fair diversifier. At 0.41, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between COST and QUAL?
Using weekly returns as of 2026-08-27: 0.41 over 3 years, with 0.10 over the last year and 0.57 over 5 years.
Is QUAL a good diversifier for COST?
A fair diversifier. At 0.41, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.41 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/cost-vs-qual.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/cost-vs-qual/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: COST correlations · QUAL correlations
