MDY vs WY: Correlation
SPDR S&P MidCap 400 ETF (MDY) and Weyerhaeuser (WY) 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 WY?
Over the past 3 years, MDY and WY moved with a correlation of 0.65, which is strong. Lately the two have drifted apart, with the 1-year correlation at 0.49 versus 0.65 over 3 years. Over 5 years the correlation is 0.68, and the annualized covariance of weekly returns is 263.4 %².
By 3-year correlation, WY places #122 of the 359 assets tracked against MDY. The last year tells two different stories: MDY led by 24.4 percentage points, +18.3% for MDY against -6.1% for WY. Across three years, the rolling one-year figure varied moderately, from 0.53 to 0.84. One caveat on sizing: WY is 1.5 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.
MDY vs WY: side by side
| MDY (SPDR S&P MidCap 400 ETF) | WY (Weyerhaeuser) | |
|---|---|---|
| 1-year return | +18.3% | -6.1% |
| 5-year return | +47.5% | -19.5% |
| Volatility (ann.) | 16.5% | 24.8% |
| Beta vs S&P 500 | 0.91 | 0.64 |
| Max drawdown (3Y) | -24.0% | -38.0% |
| Market cap | – | $17.1B |
| P/E (trailing) | – | 36.5 |
| Dividend yield | 1.02% | 3.49% |
| Expense ratio | 0.23% | – |
| Assets under management | $26.5B | – |
| Sector / category | ETF · US Small & Mid Cap | Real Estate |
On the fund side, MDY sits in the Mid-Cap Blend category at State Street Investment Management, with $26.5B under management, 400 holdings, a 0.23% expense ratio, a 1.02% trailing dividend yield.
Year-by-year returns
| Year | MDY | WY |
|---|---|---|
| 2022 | -13.3% | -20.4% |
| 2023 | +16.1% | +18.0% |
| 2024 | +13.6% | -16.6% |
| 2025 | +7.2% | -13.0% |
| 2026 | +16.4% | +1.8% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and WY good diversifiers for each other?
Only partially. A correlation of 0.65 means MDY and WY share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
FAQ
What is the correlation between MDY and WY?
As of 2026-08-27, the correlation of weekly returns between MDY and WY is 0.65 over 3 years, 0.49 over 1 year and 0.68 over 5 years.
Is WY a good diversifier for MDY?
Only partially. A correlation of 0.65 means MDY and WY share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
What does a correlation of 0.65 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/mdy-vs-wy.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/mdy-vs-wy/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: MDY correlations · WY correlations
