MDY vs WS: Correlation
Measured on weekly returns over the past three years, SPDR S&P MidCap 400 ETF (MDY) and Worthington Steel, Inc. (WS) carry a correlation of 0.64, a strong link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and WS?
Across a 3-year window, the weekly returns of MDY and WS correlate at 0.64, strong. Little has changed lately, as the 1-year reading of 0.62 lands near the 3-year figure. Stretching to 5 years gives n/a, with an annualized covariance of 522.7 %².
Among the 359 assets we track against MDY, WS ranks #132 by 3-year correlation. On 12-month performance MDY holds a 13.5-point edge, +18.3% against +4.8%. Note the risk asymmetry: WS runs 3.1 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 WS: side by side
| MDY (SPDR S&P MidCap 400 ETF) | WS (Worthington Steel, Inc.) | |
|---|---|---|
| 1-year return | +18.3% | +4.8% |
| 5-year return | +47.5% | n/a |
| Volatility (ann.) | 16.5% | 51.2% |
| Beta vs S&P 500 | 0.91 | 1.67 |
| Max drawdown (3Y) | -24.0% | -51.0% |
| Market cap | – | $1.7B |
| P/E (trailing) | – | 201.9 |
| Dividend yield | 1.02% | 1.89% |
| 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 | WS |
|---|---|---|
| 2022 | -13.3% | – |
| 2023 | +16.1% | – |
| 2024 | +13.6% | +15.4% |
| 2025 | +7.2% | +11.2% |
| 2026 | +16.4% | -0.0% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and WS good diversifiers for each other?
To a limited degree. At 0.64 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 WS?
Using weekly returns as of 2026-08-27: 0.64 over 3 years, with 0.62 over the last year and n/a over 5 years.
Is WS a good diversifier for MDY?
To a limited degree. At 0.64 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 0.64 mean?
A reading of 0.64 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/mdy-vs-ws.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/mdy-vs-ws/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: MDY correlations · WS correlations
