MDY vs QUAL: Correlation & Overlap
SPDR S&P MidCap 400 ETF (MDY) and iShares MSCI USA Quality Factor ETF (QUAL) show a very strong relationship: their 3-year correlation of weekly returns is 0.80. By holdings, the two funds overlap 0.4% by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and QUAL?
Across a 3-year window, the weekly returns of MDY and QUAL correlate at 0.80, very strong, meaning they move nearly in lockstep. The relationship has been stable: the 1-year correlation (0.77) sits close to the 3-year figure. Stretching to 5 years gives 0.85, with an annualized covariance of 185.3 %².
By 3-year correlation, QUAL places #19 of the 359 assets tracked against MDY. Twelve-month performance is nearly a tie, at +18.3% for MDY and +19.7% for QUAL. On a rolling one-year basis the correlation drifted between 0.62 and 0.91, 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 QUAL: side by side
| MDY (SPDR S&P MidCap 400 ETF) | QUAL (iShares MSCI USA Quality Factor ETF) | |
|---|---|---|
| 1-year return | +18.3% | +19.7% |
| 5-year return | +47.5% | +68.0% |
| Volatility (ann.) | 16.5% | 14.0% |
| Beta vs S&P 500 | 0.91 | 0.93 |
| Max drawdown (3Y) | -24.0% | -18.0% |
| Dividend yield | 1.02% | 0.86% |
| Expense ratio | 0.23% | 0.15% |
| Assets under management | $26.5B | $46.5B |
| Sector / category | ETF · US Small & Mid Cap | ETF · US Style |
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. QUAL, iShares's Large Blend fund, carries $46.5B under management, 123 holdings, a 0.15% expense ratio, a 0.86% trailing dividend yield.
Portfolio overlap between MDY and QUAL
The two portfolios are largely distinct: 0.4% of the funds' weight sits in the same underlying holdings (5 common positions). Correlation tells you they move together; overlap tells you why.
| Common holding | Weight in MDY | Weight in QUAL |
|---|---|---|
| CDE | 0.61% | 0.12% |
| FN | 0.43% | 0.09% |
| GGG | 0.36% | 0.09% |
| UTHR | 0.60% | 0.07% |
| RPM | 0.37% | 0.05% |
Largest positions held only by MDY: TWLO (0.95%), P (0.94%), ILMN (0.93%), FTI (0.83%), ATI (0.80%). Only by QUAL: MSFT (7.51%), AAPL (6.62%), NVDA (6.00%), META (3.75%), LLY (3.72%).
Overlap = sum of the smaller of the two weights across common holdings, from issuer disclosures as of 2026-08-26. Top 5 common positions shown.
Year-by-year returns
| Year | MDY | QUAL |
|---|---|---|
| 2022 | -13.3% | -20.5% |
| 2023 | +16.1% | +30.9% |
| 2024 | +13.6% | +22.3% |
| 2025 | +7.2% | +12.7% |
| 2026 | +16.4% | +13.5% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and QUAL good diversifiers for each other?
Not really. At 0.80, the two trade almost as one position, and owning both buys little extra protection.
FAQ
What is the correlation between MDY and QUAL?
Using weekly returns as of 2026-08-27: 0.80 over 3 years, with 0.77 over the last year and 0.85 over 5 years.
Is QUAL a good diversifier for MDY?
Not really. At 0.80, the two trade almost as one position, and owning both buys little extra protection.
How much do MDY and QUAL overlap?
Per the issuers' own portfolio disclosures (2026-08-26), the overlap is 0.4% by weight over 5 common positions.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/mdy-vs-qual.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/mdy-vs-qual/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: MDY correlations · QUAL correlations
