CNXN vs MDY: Correlation
Measured on weekly returns over the past three years, PC Connection, Inc. (CNXN) and SPDR S&P MidCap 400 ETF (MDY) carry a correlation of 0.57, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CNXN and MDY?
Across a 3-year window, the weekly returns of CNXN and MDY correlate at 0.57, moderate. The relationship has been stable: the 1-year correlation (0.54) sits close to the 3-year figure. Stretching to 5 years gives 0.52, with an annualized covariance of 258.8 %².
Few assets follow CNXN as closely as MDY, which ranks #2 of 12 tracked partners. Over the last 12 months CNXN came out ahead by 7.9 percentage points (+26.2% against +18.3%). Risk is not evenly split, since CNXN carries 1.7 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.
CNXN vs MDY: side by side
| CNXN (PC Connection, Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +26.2% | +18.3% |
| 5-year return | +75.2% | +47.5% |
| Volatility (ann.) | 27.3% | 16.5% |
| Beta vs S&P 500 | 0.86 | 0.91 |
| Max drawdown (3Y) | -26.3% | -24.0% |
| Market cap | $2.0B | – |
| P/E (trailing) | 21.0 | – |
| Dividend yield | 0.88% | 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 | CNXN | MDY |
|---|---|---|
| 2022 | +9.4% | -13.3% |
| 2023 | +44.3% | +16.1% |
| 2024 | +3.7% | +13.6% |
| 2025 | -15.8% | +7.2% |
| 2026 | +40.7% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are CNXN and MDY good diversifiers for each other?
To a limited degree. At 0.57 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
FAQ
What is the correlation between CNXN and MDY?
Using weekly returns as of 2026-08-27: 0.57 over 3 years, with 0.54 over the last year and 0.52 over 5 years.
Is MDY a good diversifier for CNXN?
To a limited degree. At 0.57 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
What does a correlation of 0.57 mean?
A reading of 0.57 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/cnxn-vs-mdy.json
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[](https://www.pairbook.io/pair/cnxn-vs-mdy/)
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Related comparisons
Hubs: CNXN correlations · MDY correlations
