DCI vs MDY: Correlation
How closely do Donaldson Company, Inc. (DCI) and SPDR S&P MidCap 400 ETF (MDY) trade together? Their weekly returns over three years give a correlation of 0.69, which is strong.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are DCI and MDY?
Across a 3-year window, the weekly returns of DCI and MDY correlate at 0.69, strong. Lately the two have drifted apart, with the 1-year correlation at 0.58 versus 0.69 over 3 years. Stretching to 5 years gives 0.73, with an annualized covariance of 238.4 %².
In DCI's tracked universe of 15 assets, MDY sits right near the top at #1. Neither side won the trailing year by much: +14.0% against +18.3%.
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.
DCI vs MDY: side by side
| DCI (Donaldson Company, Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +14.0% | +18.3% |
| 5-year return | +44.4% | +47.5% |
| Volatility (ann.) | 21.0% | 16.5% |
| Beta vs S&P 500 | 0.74 | 0.91 |
| Max drawdown (3Y) | -26.0% | -24.0% |
| Market cap | – | – |
| P/E (trailing) | 24.8 | – |
| Dividend yield | 1.30% | 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 | DCI | MDY |
|---|---|---|
| 2022 | +1.0% | -13.3% |
| 2023 | +12.8% | +16.1% |
| 2024 | +4.6% | +13.6% |
| 2025 | +33.7% | +7.2% |
| 2026 | +5.3% | +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 DCI at a 0.3% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are DCI and MDY good diversifiers for each other?
To a limited degree. At 0.69 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 DCI and MDY?
As of 2026-08-27, the correlation of weekly returns between DCI and MDY is 0.69 over 3 years, 0.58 over 1 year and 0.73 over 5 years.
Is MDY a good diversifier for DCI?
To a limited degree. At 0.69 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 0.69 mean?
On the −1 to +1 scale, 0.69 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
$ curl https://www.pairbook.io/api/v1/pairs/dci-vs-mdy.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/dci-vs-mdy/)
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Related comparisons
Hubs: DCI correlations · MDY correlations
