MDY vs QQQ: Correlation & Overlap
How closely do SPDR S&P MidCap 400 ETF (MDY) and Invesco QQQ Trust (QQQ) trade together? Their weekly returns over three years give a correlation of 0.67, which is strong. Looking through to holdings, 0% of the two portfolios is the same by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and QQQ?
Across a 3-year window, the weekly returns of MDY and QQQ correlate at 0.67, strong. The link has loosened recently: the 1-year correlation (0.55) runs below the 3-year figure (0.67). Stretching to 5 years gives 0.74, with an annualized covariance of 215.5 %².
Within MDY's tracked universe of 359 assets, QQQ comes in at #94 by 3-year correlation. Over the last 12 months QQQ came out ahead by 8.0 percentage points (+18.3% against +26.3%). The rolling one-year correlation moved between 0.50 and 0.84 over the past three years, a moderate range.
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 QQQ: side by side
| MDY (SPDR S&P MidCap 400 ETF) | QQQ (Invesco QQQ Trust) | |
|---|---|---|
| 1-year return | +18.3% | +26.3% |
| 5-year return | +47.5% | +95.4% |
| Volatility (ann.) | 16.5% | 19.6% |
| Beta vs S&P 500 | 0.91 | 1.28 |
| Max drawdown (3Y) | -24.0% | -22.8% |
| Dividend yield | 1.02% | 0.44% |
| Expense ratio | 0.23% | 0.18% |
| Assets under management | $26.5B | $452.8B |
| Sector / category | ETF · US Small & Mid Cap | ETF · US Growth & Tech |
On the fund side, MDY sits in the Mid-Cap Blend category at State Street Investment Management, with $26.5B under management, 400 holdings, a 0.23% expense ratio, a 1.02% trailing dividend yield. QQQ is a Large Growth fund from Invesco: $452.8B under management, 104 holdings, a 0.18% expense ratio, a 0.44% trailing dividend yield.
Portfolio overlap between MDY and QQQ
The two portfolios are largely distinct, with 0 holdings in common adding up to 0% of fund weight. Where correlation shows the co-movement, the overlap shows its source.
Largest positions held only by MDY: TWLO (0.95%), P (0.94%), ILMN (0.93%), FTI (0.83%), ATI (0.80%). Only by QQQ: NVDA (8.15%), AAPL (7.39%), MSFT (5.93%), MU (4.69%), AMZN (4.50%).
Overlap = sum of the smaller of the two weights across common holdings, from issuer disclosures as of 2026-08-26.
Year-by-year returns
| Year | MDY | QQQ |
|---|---|---|
| 2022 | -13.3% | -32.6% |
| 2023 | +16.1% | +54.9% |
| 2024 | +13.6% | +25.6% |
| 2025 | +7.2% | +20.8% |
| 2026 | +16.4% | +17.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and QQQ 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 MDY and QQQ?
Using weekly returns as of 2026-08-27: 0.67 over 3 years, with 0.55 over the last year and 0.74 over 5 years.
Is QQQ a good diversifier for MDY?
Somewhat, no more. With 0.67 correlation, most large moves hit both names, and the diversification benefit stays modest.
How much do MDY and QQQ overlap?
Per the issuers' own portfolio disclosures (2026-08-26), the overlap is 0% by weight over 0 common positions.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/mdy-vs-qqq.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/mdy-vs-qqq/)
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Related comparisons
Hubs: MDY correlations · QQQ correlations
