GM vs MDY: Correlation
How closely do General Motors (GM) and SPDR S&P MidCap 400 ETF (MDY) trade together? Their weekly returns over three years give a correlation of 0.51, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are GM and MDY?
Across a 3-year window, the weekly returns of GM and MDY correlate at 0.51, moderate. The relationship has been stable: the 1-year correlation (0.44) sits close to the 3-year figure. Stretching to 5 years gives 0.64, with an annualized covariance of 269.1 %².
By 3-year correlation, MDY places #9 of the 35 assets tracked against GM. The last year tells two different stories: GM led by 29.7 percentage points, +48.0% for GM against +18.3% for MDY. The rolling one-year correlation moved between 0.43 and 0.81 over the past three years, a moderate range. Note the risk asymmetry: GM 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.
GM vs MDY: side by side
| GM (General Motors) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +48.0% | +18.3% |
| 5-year return | +82.5% | +47.5% |
| Volatility (ann.) | 32.2% | 16.5% |
| Beta vs S&P 500 | 0.98 | 0.91 |
| Max drawdown (3Y) | -29.1% | -24.0% |
| Market cap | $77.9B | – |
| P/E (trailing) | 38.6 | – |
| Dividend yield | 0.76% | 1.02% |
| Expense ratio | – | 0.23% |
| Assets under management | – | $26.5B |
| Sector / category | Consumer Discretionary | 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 | GM | MDY |
|---|---|---|
| 2022 | -42.4% | -13.3% |
| 2023 | +7.9% | +16.1% |
| 2024 | +49.8% | +13.6% |
| 2025 | +54.2% | +7.2% |
| 2026 | +6.5% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are GM and MDY good diversifiers for each other?
To a limited degree. At 0.51 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 GM and MDY?
Using weekly returns as of 2026-08-27: 0.51 over 3 years, with 0.44 over the last year and 0.64 over 5 years.
Is MDY a good diversifier for GM?
To a limited degree. At 0.51 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 0.51 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: GM correlations · MDY correlations
