AYI vs MDY: Correlation
Acuity Inc. (AYI) and SPDR S&P MidCap 400 ETF (MDY) show a strong relationship: their 3-year correlation of weekly returns is 0.60.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are AYI and MDY?
On 3 years of weekly data the AYI/MDY correlation comes out at 0.60, strong. The link has loosened recently: the 1-year correlation (0.46) runs below the 3-year figure (0.60). The 5-year figure is 0.63, and annualized covariance runs at 295.1 %².
Few assets follow AYI as closely as MDY, which ranks #1 of 12 tracked partners. Their recent paths diverged sharply: over the last 12 months MDY outperformed by 15.7 percentage points (+2.6% for AYI against +18.3% for MDY). Risk is not evenly split, since AYI carries 1.8 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.
AYI vs MDY: side by side
| AYI (Acuity Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +2.6% | +18.3% |
| 5-year return | +86.6% | +47.5% |
| Volatility (ann.) | 30.1% | 16.5% |
| Beta vs S&P 500 | 1.13 | 0.91 |
| Max drawdown (3Y) | -33.7% | -24.0% |
| Market cap | $10.2B | – |
| P/E (trailing) | 22.7 | – |
| Dividend yield | 0.22% | 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 | AYI | MDY |
|---|---|---|
| 2022 | -21.5% | -13.3% |
| 2023 | +24.1% | +16.1% |
| 2024 | +42.9% | +13.6% |
| 2025 | +23.5% | +7.2% |
| 2026 | -4.9% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
Keep in mind that MDY holds AYI at a 0.28% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are AYI and MDY good diversifiers for each other?
Only partially. A correlation of 0.60 means AYI and MDY share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
FAQ
What is the correlation between AYI and MDY?
As of 2026-08-27, the correlation of weekly returns between AYI and MDY is 0.60 over 3 years, 0.46 over 1 year and 0.63 over 5 years.
Is MDY a good diversifier for AYI?
Only partially. A correlation of 0.60 means AYI and MDY share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
What does a correlation of 0.60 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: AYI correlations · MDY correlations
