MDY vs WWD: Correlation
SPDR S&P MidCap 400 ETF (MDY) and Woodward, Inc. (WWD) show a strong relationship: their 3-year correlation of weekly returns is 0.65.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and WWD?
On 3 years of weekly data the MDY/WWD correlation comes out at 0.65, strong. Recent behaviour matches the longer record: 0.65 over 1 year against 0.65 over 3. The 5-year figure is 0.67, and annualized covariance runs at 356.0 %².
Among the 359 assets we track against MDY, WWD ranks #121 by 3-year correlation. Their recent paths diverged sharply: over the last 12 months WWD outperformed by 20.9 percentage points (+18.3% for MDY against +39.2% for WWD). Note the risk asymmetry: WWD runs 2.0 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
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.
MDY vs WWD: side by side
| MDY (SPDR S&P MidCap 400 ETF) | WWD (Woodward, Inc.) | |
|---|---|---|
| 1-year return | +18.3% | +39.2% |
| 5-year return | +47.5% | +191.7% |
| Volatility (ann.) | 16.5% | 33.5% |
| Beta vs S&P 500 | 0.91 | 1.09 |
| Max drawdown (3Y) | -24.0% | -23.6% |
| Market cap | – | $20.4B |
| P/E (trailing) | – | 38.5 |
| Dividend yield | 1.02% | 0.28% |
| Expense ratio | 0.23% | – |
| Assets under management | $26.5B | – |
| Sector / category | ETF · US Small & Mid Cap | US Listed |
MDY, State Street Investment Management's Mid-Cap Blend fund, carries $26.5B under management, 400 holdings, a 0.23% expense ratio, a 1.02% trailing dividend yield.
Year-by-year returns
| Year | MDY | WWD |
|---|---|---|
| 2022 | -13.3% | -11.1% |
| 2023 | +16.1% | +42.0% |
| 2024 | +13.6% | +23.0% |
| 2025 | +7.2% | +82.6% |
| 2026 | +16.4% | +14.9% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
WWD represents 0.57% of MDY's portfolio, so part of any move in MDY is WWD itself, and the correlation between them is partly mechanical.
Are MDY and WWD good diversifiers for each other?
To a limited degree. At 0.65 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 MDY and WWD?
As of 2026-08-27, the correlation of weekly returns between MDY and WWD is 0.65 over 3 years, 0.65 over 1 year and 0.67 over 5 years.
Is WWD a good diversifier for MDY?
To a limited degree. At 0.65 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 0.65 mean?
On the −1 to +1 scale, 0.65 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/mdy-vs-wwd.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/mdy-vs-wwd/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: MDY correlations · WWD correlations
