SPY vs WDC: Correlation
How closely do SPDR S&P 500 ETF Trust (SPY) and Western Digital (WDC) trade together? Their weekly returns over three years give a correlation of 0.54, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPY and WDC?
On 3 years of weekly data the SPY/WDC correlation comes out at 0.54, moderate. The past 12 months show a weaker link (0.39) than the 3-year average (0.54). The 5-year figure is 0.54, and annualized covariance runs at 449.1 %².
By 3-year correlation, WDC places #326 of the 4755 assets tracked against SPY. The last year tells two different stories: WDC led by 453.7 percentage points, +20.6% for SPY against +474.3% for WDC. The rolling one-year correlation moved between 0.38 and 0.81 over the past three years, a moderate range. One caveat on sizing: WDC is 4.0 times as volatile as the other leg, so an equal-dollar split is far from equal-risk.
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 WDC: side by side
| SPY (SPDR S&P 500 ETF Trust) | WDC (Western Digital) | |
|---|---|---|
| 1-year return | +20.6% | +474.3% |
| 5-year return | +82.4% | +889.2% |
| Volatility (ann.) | 14.5% | 58.0% |
| Beta vs S&P 500 | 1.00 | 2.15 |
| Max drawdown (3Y) | -18.8% | -49.6% |
| Market cap | – | $166.6B |
| P/E (trailing) | – | 17.4 |
| Dividend yield | 1.01% | 0.11% |
| Expense ratio | 0.09% | – |
| Assets under management | $795.3B | – |
| Sector / category | ETF · US Large Cap | Information Technology |
On the fund side, SPY sits in the Large Blend category at State Street Investment Management, with $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | SPY | WDC |
|---|---|---|
| 2022 | -18.2% | -51.6% |
| 2023 | +26.2% | +66.0% |
| 2024 | +24.9% | +13.9% |
| 2025 | +17.7% | +283.7% |
| 2026 | +13.7% | +168.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
Keep in mind that SPY holds WDC at a 0.24% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are SPY and WDC good diversifiers for each other?
To a limited degree. At 0.54 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
FAQ
What is the correlation between SPY and WDC?
The SPY/WDC correlation stands at 0.54 on a 3-year window (1 year: 0.39, 5 years: 0.54), computed from weekly returns as of 2026-08-27.
Is WDC a good diversifier for SPY?
To a limited degree. At 0.54 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
What does a correlation of 0.54 mean?
A reading of 0.54 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/spy-vs-wdc.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/spy-vs-wdc/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: SPY correlations · WDC correlations
