ACA vs MDY: Correlation
Arcosa, Inc. (ACA) and SPDR S&P MidCap 400 ETF (MDY) show a strong relationship: their 3-year correlation of weekly returns is 0.68.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ACA and MDY?
On 3 years of weekly data the ACA/MDY correlation comes out at 0.68, strong. The past 12 months show a weaker link (0.44) than the 3-year average (0.68). The 5-year figure is 0.61, and annualized covariance runs at 355.8 %².
In ACA's tracked universe of 23 assets, MDY sits right near the top at #2. Their recent paths diverged sharply: over the last 12 months ACA outperformed by 28.7 percentage points (+47.0% for ACA against +18.3% for MDY). Note the risk asymmetry: ACA runs 1.9 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.
ACA vs MDY: side by side
| ACA (Arcosa, Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +47.0% | +18.3% |
| 5-year return | +186.5% | +47.5% |
| Volatility (ann.) | 31.9% | 16.5% |
| Beta vs S&P 500 | 1.23 | 0.91 |
| Max drawdown (3Y) | -36.6% | -24.0% |
| Market cap | $7.1B | – |
| P/E (trailing) | 32.5 | – |
| Dividend yield | 0.14% | 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 | ACA | MDY |
|---|---|---|
| 2022 | +3.5% | -13.3% |
| 2023 | +52.5% | +16.1% |
| 2024 | +17.3% | +13.6% |
| 2025 | +10.2% | +7.2% |
| 2026 | +37.0% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are ACA and MDY good diversifiers for each other?
Only partially. A correlation of 0.68 means ACA 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 ACA and MDY?
The ACA/MDY correlation stands at 0.68 on a 3-year window (1 year: 0.44, 5 years: 0.61), computed from weekly returns as of 2026-08-27.
Is MDY a good diversifier for ACA?
Only partially. A correlation of 0.68 means ACA 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 0.68 mean?
On the −1 to +1 scale, 0.68 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: ACA correlations · MDY correlations
