ALSN vs MDY: Correlation
Measured on weekly returns over the past three years, Allison Transmission Holdings, Inc. (ALSN) and SPDR S&P MidCap 400 ETF (MDY) carry a correlation of 0.61, a strong link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ALSN and MDY?
Across a 3-year window, the weekly returns of ALSN and MDY correlate at 0.61, strong. Little has changed lately, as the 1-year reading of 0.52 lands near the 3-year figure. Stretching to 5 years gives 0.60, with an annualized covariance of 298.7 %².
In ALSN's tracked universe of 12 assets, MDY sits right near the top at #2. Correlation aside, the last 12 months split them widely, with ALSN ahead by 28.0 points (+46.3% versus +18.3%). Risk is not evenly split, since ALSN carries 1.8 times the volatility of the other side.
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.
ALSN vs MDY: side by side
| ALSN (Allison Transmission Holdings, Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +46.3% | +18.3% |
| 5-year return | +271.5% | +47.5% |
| Volatility (ann.) | 29.8% | 16.5% |
| Beta vs S&P 500 | 0.81 | 0.91 |
| Max drawdown (3Y) | -33.6% | -24.0% |
| Market cap | $10.7B | – |
| P/E (trailing) | 20.4 | – |
| Dividend yield | 0.87% | 1.02% |
| Expense ratio | – | 0.23% |
| Assets under management | – | $26.5B |
| Sector / category | US Listed | ETF · US Small & Mid Cap |
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 | ALSN | MDY |
|---|---|---|
| 2022 | +16.9% | -13.3% |
| 2023 | +42.3% | +16.1% |
| 2024 | +88.0% | +13.6% |
| 2025 | -8.3% | +7.2% |
| 2026 | +32.9% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
Keep in mind that MDY holds ALSN at a 0.29% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are ALSN and MDY good diversifiers for each other?
Somewhat, no more. With 0.61 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between ALSN and MDY?
As of 2026-08-27, the correlation of weekly returns between ALSN and MDY is 0.61 over 3 years, 0.52 over 1 year and 0.60 over 5 years.
Is MDY a good diversifier for ALSN?
Somewhat, no more. With 0.61 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.61 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.
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Related comparisons
Hubs: ALSN correlations · MDY correlations
