GATX vs MDY: Correlation
Measured on weekly returns over the past three years, GATX Corporation (GATX) and SPDR S&P MidCap 400 ETF (MDY) carry a correlation of 0.63, a strong link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are GATX and MDY?
On 3 years of weekly data the GATX/MDY correlation comes out at 0.63, strong. The past 12 months show a weaker link (0.47) than the 3-year average (0.63). The 5-year figure is 0.64, and annualized covariance runs at 253.3 %².
Few assets follow GATX as closely as MDY, which ranks #1 of 10 tracked partners. The trailing year gives MDY the advantage: +9.1% versus +18.3%, a 9.2-point spread.
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.
GATX vs MDY: side by side
| GATX (GATX Corporation) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +9.1% | +18.3% |
| 5-year return | +112.2% | +47.5% |
| Volatility (ann.) | 24.2% | 16.5% |
| Beta vs S&P 500 | 0.78 | 0.91 |
| Max drawdown (3Y) | -18.1% | -24.0% |
| Market cap | $6.3B | – |
| P/E (trailing) | 17.7 | – |
| Dividend yield | 1.42% | 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 | GATX | MDY |
|---|---|---|
| 2022 | +4.2% | -13.3% |
| 2023 | +15.2% | +16.1% |
| 2024 | +31.1% | +13.6% |
| 2025 | +11.1% | +7.2% |
| 2026 | +6.0% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 0.17% of MDY is GATX itself, so the fund partly moves with the stock by construction.
Are GATX and MDY good diversifiers for each other?
Somewhat, no more. With 0.63 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between GATX and MDY?
Using weekly returns as of 2026-08-27: 0.63 over 3 years, with 0.47 over the last year and 0.64 over 5 years.
Is MDY a good diversifier for GATX?
Somewhat, no more. With 0.63 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.63 mean?
On the −1 to +1 scale, 0.63 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
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Related comparisons
Hubs: GATX correlations · MDY correlations
