MDY vs NDSN: Correlation
How closely do SPDR S&P MidCap 400 ETF (MDY) and Nordson Corporation (NDSN) trade together? Their weekly returns over three years give a correlation of 0.71, which is strong.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and NDSN?
Across a 3-year window, the weekly returns of MDY and NDSN correlate at 0.71, strong. Lately the two have drifted apart, with the 1-year correlation at 0.56 versus 0.71 over 3 years. Stretching to 5 years gives 0.74, with an annualized covariance of 289.5 %².
Among the 359 assets we track against MDY, NDSN ranks #58 by 3-year correlation. Correlation aside, the last 12 months split them widely, with NDSN ahead by 30.2 points (+18.3% versus +48.5%). Stability stands out here, with the rolling one-year correlation confined to 0.69 through 0.83.
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.
MDY vs NDSN: side by side
| MDY (SPDR S&P MidCap 400 ETF) | NDSN (Nordson Corporation) | |
|---|---|---|
| 1-year return | +18.3% | +48.5% |
| 5-year return | +47.5% | +46.5% |
| Volatility (ann.) | 16.5% | 24.7% |
| Beta vs S&P 500 | 0.91 | 0.97 |
| Max drawdown (3Y) | -24.0% | -39.1% |
| Market cap | – | $18.4B |
| P/E (trailing) | – | 33.5 |
| Dividend yield | 1.02% | 0.98% |
| Expense ratio | 0.23% | – |
| Assets under management | $26.5B | – |
| Sector / category | ETF · US Small & Mid Cap | Industrials |
MDY is a Mid-Cap Blend fund from State Street Investment Management: $26.5B under management, 400 holdings, a 0.23% expense ratio, a 1.02% trailing dividend yield.
Year-by-year returns
| Year | MDY | NDSN |
|---|---|---|
| 2022 | -13.3% | -5.9% |
| 2023 | +16.1% | +12.4% |
| 2024 | +13.6% | -20.1% |
| 2025 | +7.2% | +17.0% |
| 2026 | +16.4% | +38.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and NDSN good diversifiers for each other?
To a limited degree. At 0.71 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 MDY and NDSN?
Using weekly returns as of 2026-08-27: 0.71 over 3 years, with 0.56 over the last year and 0.74 over 5 years.
Is NDSN a good diversifier for MDY?
To a limited degree. At 0.71 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 0.71 mean?
A reading of 0.71 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/mdy-vs-ndsn.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/mdy-vs-ndsn/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: MDY correlations · NDSN correlations
