PLOW vs SPY: Correlation
Douglas Dynamics, Inc. (PLOW) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.24.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PLOW and SPY?
On 3 years of weekly data the PLOW/SPY correlation comes out at 0.24, weak. The link has loosened recently: the 1-year correlation (0.03) runs below the 3-year figure (0.24). The 5-year figure is 0.41, and annualized covariance runs at 115.0 %².
Among the 10 assets we track against PLOW, SPY sits near the bottom by co-movement, at rank #6. The trailing year gives PLOW the advantage: +28.2% versus +20.6%, a 7.6-point spread. Note the risk asymmetry: PLOW runs 2.3 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.
PLOW vs SPY: side by side
| PLOW (Douglas Dynamics, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +28.2% | +20.6% |
| 5-year return | +30.5% | +82.4% |
| Volatility (ann.) | 32.7% | 14.5% |
| Beta vs S&P 500 | 0.55 | 1.00 |
| Max drawdown (3Y) | -29.6% | -18.8% |
| Market cap | $1.0B | – |
| P/E (trailing) | 18.9 | – |
| Dividend yield | 2.83% | 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 | PLOW | SPY |
|---|---|---|
| 2022 | -4.0% | -18.2% |
| 2023 | -14.7% | +26.2% |
| 2024 | -16.5% | +24.9% |
| 2025 | +43.8% | +17.7% |
| 2026 | +30.9% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PLOW and SPY good diversifiers for each other?
Reasonably. At 0.24, PLOW and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between PLOW and SPY?
As of 2026-08-27, the correlation of weekly returns between PLOW and SPY is 0.24 over 3 years, 0.03 over 1 year and 0.41 over 5 years.
Is SPY a good diversifier for PLOW?
Reasonably. At 0.24, PLOW and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.24 mean?
On the −1 to +1 scale, 0.24 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.
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Related comparisons
Hubs: PLOW correlations · SPY correlations
