MDU vs SPY: Correlation
How closely do MDU Resources Group, Inc. (MDU) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.32, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDU and SPY?
Across a 3-year window, the weekly returns of MDU and SPY correlate at 0.32, moderate. The past 12 months show a weaker link (-0.05) than the 3-year average (0.32). Stretching to 5 years gives 0.41, with an annualized covariance of 115.2 %².
SPY is close to the least connected end of MDU's tracked universe, ranking #7 of 11. On 12-month performance MDU holds a 5.7-point edge, +26.3% against +20.6%. Note the risk asymmetry: MDU runs 1.7 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.
MDU vs SPY: side by side
| MDU (MDU Resources Group, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +26.3% | +20.6% |
| 5-year return | +90.7% | +82.4% |
| Volatility (ann.) | 25.2% | 14.5% |
| Beta vs S&P 500 | 0.55 | 1.00 |
| Max drawdown (3Y) | -21.5% | -18.8% |
| Market cap | $4.2B | – |
| P/E (trailing) | 21.7 | – |
| Dividend yield | 2.76% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | US Listed | ETF · US Large Cap |
SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | MDU | SPY |
|---|---|---|
| 2022 | +1.5% | -18.2% |
| 2023 | -1.9% | +26.2% |
| 2024 | +68.0% | +24.9% |
| 2025 | +11.8% | +17.7% |
| 2026 | +4.8% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDU and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.32 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between MDU and SPY?
As of 2026-08-27, the correlation of weekly returns between MDU and SPY is 0.32 over 3 years, -0.05 over 1 year and 0.41 over 5 years.
Is SPY a good diversifier for MDU?
Yes, to a useful degree: a correlation of 0.32 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.32 mean?
A reading of 0.32 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: MDU correlations · SPY correlations
