LFUS vs MDY: Correlation
Measured on weekly returns over the past three years, Littelfuse, Inc. (LFUS) and SPDR S&P MidCap 400 ETF (MDY) carry a correlation of 0.67, a strong link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are LFUS and MDY?
Across a 3-year window, the weekly returns of LFUS and MDY correlate at 0.67, strong. Recent behaviour matches the longer record: 0.58 over 1 year against 0.67 over 3. Stretching to 5 years gives 0.67, with an annualized covariance of 387.5 %².
Within LFUS's tracked universe of 25 assets, MDY comes in at #4 by 3-year correlation. The last year tells two different stories: LFUS led by 43.7 percentage points, +62.0% for LFUS against +18.3% for MDY. One caveat on sizing: LFUS is 2.1 times as volatile as the other leg, so an equal-dollar split is far from equal-risk.
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.
LFUS vs MDY: side by side
| LFUS (Littelfuse, Inc.) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +62.0% | +18.3% |
| 5-year return | +53.7% | +47.5% |
| Volatility (ann.) | 35.3% | 16.5% |
| Beta vs S&P 500 | 1.44 | 0.91 |
| Max drawdown (3Y) | -45.0% | -24.0% |
| Market cap | $10.7B | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.72% | 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 | LFUS | MDY |
|---|---|---|
| 2022 | -29.4% | -13.3% |
| 2023 | +22.7% | +16.1% |
| 2024 | -11.0% | +13.6% |
| 2025 | +8.6% | +7.2% |
| 2026 | +67.5% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 0.29% of MDY is LFUS itself, so the fund partly moves with the stock by construction.
Are LFUS and MDY good diversifiers for each other?
Somewhat, no more. With 0.67 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between LFUS and MDY?
Using weekly returns as of 2026-08-27: 0.67 over 3 years, with 0.58 over the last year and 0.67 over 5 years.
Is MDY a good diversifier for LFUS?
Somewhat, no more. With 0.67 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.67 mean?
On the −1 to +1 scale, 0.67 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.
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Related comparisons
Hubs: LFUS correlations · MDY correlations
