GFF vs MDY: Correlation
How closely do Griffon Corporation (GFF) and SPDR S&P MidCap 400 ETF (MDY) trade together? Their weekly returns over three years give a correlation of 0.67, which is strong.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are GFF and MDY?
Across a 3-year window, the weekly returns of GFF and MDY correlate at 0.67, strong. Recent behaviour matches the longer record: 0.76 over 1 year against 0.67 over 3. Stretching to 5 years gives 0.61, with an annualized covariance of 425.6 %².
By 3-year correlation, MDY places #5 of the 26 assets tracked against GFF. Over the last 12 months GFF came out ahead by 10.1 percentage points (+28.4% against +18.3%). Risk is not evenly split, since GFF carries 2.3 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.
GFF vs MDY: side by side
| GFF (Griffon Corporation) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +28.4% | +18.3% |
| 5-year return | +396.8% | +47.5% |
| Volatility (ann.) | 38.7% | 16.5% |
| Beta vs S&P 500 | 1.14 | 0.91 |
| Max drawdown (3Y) | -27.9% | -24.0% |
| Market cap | $4.5B | – |
| P/E (trailing) | 21.1 | – |
| Dividend yield | 0.83% | 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 | GFF | MDY |
|---|---|---|
| 2022 | +36.9% | -13.3% |
| 2023 | +84.0% | +16.1% |
| 2024 | +18.0% | +13.6% |
| 2025 | +4.4% | +7.2% |
| 2026 | +35.4% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are GFF and MDY good diversifiers for each other?
Somewhat, no more. With 0.67 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between GFF and MDY?
Using weekly returns as of 2026-08-27: 0.67 over 3 years, with 0.76 over the last year and 0.61 over 5 years.
Is MDY a good diversifier for GFF?
Somewhat, no more. With 0.67 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.67 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: GFF correlations · MDY correlations
