CNM vs MDY: Correlation
How closely do Core & Main, Inc. (CNM) and SPDR S&P MidCap 400 ETF (MDY) trade together? Their weekly returns over three years give a correlation of 0.59, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CNM and MDY?
Across a 3-year window, the weekly returns of CNM and MDY correlate at 0.59, moderate. Recent behaviour matches the longer record: 0.49 over 1 year against 0.59 over 3. Stretching to 5 years gives 0.60, with an annualized covariance of 383.4 %².
Few assets follow CNM as closely as MDY, which ranks #2 of 17 tracked partners. Their recent paths diverged sharply: over the last 12 months MDY outperformed by 51.8 percentage points (-33.5% for CNM against +18.3% for MDY). Note the risk asymmetry: CNM runs 2.4 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.
CNM vs MDY: side by side
| CNM (Core & Main, Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | -33.5% | +18.3% |
| 5-year return | +63.1% | +47.5% |
| Volatility (ann.) | 39.7% | 16.5% |
| Beta vs S&P 500 | 1.19 | 0.91 |
| Max drawdown (3Y) | -38.7% | -24.0% |
| Market cap | $8.5B | – |
| P/E (trailing) | 18.4 | – |
| Dividend yield | 0.00% | 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 | CNM | MDY |
|---|---|---|
| 2022 | -36.4% | -13.3% |
| 2023 | +109.3% | +16.1% |
| 2024 | +26.0% | +13.6% |
| 2025 | +2.1% | +7.2% |
| 2026 | -15.8% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 0.22% of MDY is CNM itself, so the fund partly moves with the stock by construction.
Are CNM and MDY good diversifiers for each other?
Somewhat, no more. With 0.59 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between CNM and MDY?
The CNM/MDY correlation stands at 0.59 on a 3-year window (1 year: 0.49, 5 years: 0.60), computed from weekly returns as of 2026-08-27.
Is MDY a good diversifier for CNM?
Somewhat, no more. With 0.59 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.59 mean?
On the −1 to +1 scale, 0.59 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.
Use this data
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Related comparisons
Hubs: CNM correlations · MDY correlations
