MDY vs NTRS: Correlation
SPDR S&P MidCap 400 ETF (MDY) and Northern Trust (NTRS) show a strong relationship: their 3-year correlation of weekly returns is 0.74.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and NTRS?
Across a 3-year window, the weekly returns of MDY and NTRS correlate at 0.74, strong. The past 12 months show a weaker link (0.54) than the 3-year average (0.74). Stretching to 5 years gives 0.73, with an annualized covariance of 286.8 %².
Among the 359 assets we track against MDY, NTRS ranks #38 by 3-year correlation. Correlation aside, the last 12 months split them widely, with NTRS ahead by 26.5 points (+18.3% versus +44.8%). On a rolling one-year basis the correlation drifted between 0.52 and 0.86, a moderate band.
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 NTRS: side by side
| MDY (SPDR S&P MidCap 400 ETF) | NTRS (Northern Trust) | |
|---|---|---|
| 1-year return | +18.3% | +44.8% |
| 5-year return | +47.5% | +83.2% |
| Volatility (ann.) | 16.5% | 23.7% |
| Beta vs S&P 500 | 0.91 | 1.08 |
| Max drawdown (3Y) | -24.0% | -25.2% |
| Market cap | – | $34.1B |
| P/E (trailing) | – | 16.1 |
| Dividend yield | 1.02% | 1.71% |
| Expense ratio | 0.23% | – |
| Assets under management | $26.5B | – |
| Sector / category | ETF · US Small & Mid Cap | Financials |
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 | NTRS |
|---|---|---|
| 2022 | -13.3% | -23.8% |
| 2023 | +16.1% | -1.0% |
| 2024 | +13.6% | +25.6% |
| 2025 | +7.2% | +36.9% |
| 2026 | +16.4% | +37.8% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and NTRS good diversifiers for each other?
Somewhat, no more. With 0.74 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between MDY and NTRS?
As of 2026-08-27, the correlation of weekly returns between MDY and NTRS is 0.74 over 3 years, 0.54 over 1 year and 0.73 over 5 years.
Is NTRS a good diversifier for MDY?
Somewhat, no more. With 0.74 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.74 mean?
On the −1 to +1 scale, 0.74 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/mdy-vs-ntrs.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/mdy-vs-ntrs/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: MDY correlations · NTRS correlations
