IVV vs MDY: Correlation & Overlap
Measured on weekly returns over the past three years, iShares Core S&P 500 ETF (IVV) and SPDR S&P MidCap 400 ETF (MDY) carry a correlation of 0.80, a very strong link. By holdings, the two funds overlap 0% by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are IVV and MDY?
Across a 3-year window, the weekly returns of IVV and MDY correlate at 0.80, very strong, meaning they move nearly in lockstep. Lately the two have drifted apart, with the 1-year correlation at 0.65 versus 0.80 over 3 years. Stretching to 5 years gives 0.86, with an annualized covariance of 191.2 %².
Among the 122 assets we track against IVV, MDY ranks #34 by 3-year correlation. Their 12-month results are close: +20.7% for IVV against +18.3% for MDY. On a rolling one-year basis the correlation drifted between 0.64 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.
IVV vs MDY: side by side
| IVV (iShares Core S&P 500 ETF) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +20.7% | +18.3% |
| 5-year return | +83.0% | +47.5% |
| Volatility (ann.) | 14.5% | 16.5% |
| Beta vs S&P 500 | 1.00 | 0.91 |
| Max drawdown (3Y) | -18.8% | -24.0% |
| Dividend yield | 1.09% | 1.02% |
| Expense ratio | 0.03% | 0.23% |
| Assets under management | $869.2B | $26.5B |
| Sector / category | ETF · US Large Cap | ETF · US Small & Mid Cap |
On the fund side, IVV sits in the Large Blend category at iShares, with $869.2B under management, 503 holdings, a 0.03% expense ratio, a 1.09% trailing dividend yield. 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.
Portfolio overlap between IVV and MDY
The two portfolios are largely distinct: 0% of the funds' weight sits in the same underlying holdings (0 common positions). Correlation tells you they move together; overlap tells you why.
Largest positions held only by IVV: NVDA (7.67%), AAPL (6.96%), MSFT (5.57%), AMZN (3.85%), GOOGL (3.03%). Only by MDY: TWLO (0.95%), P (0.94%), ILMN (0.93%), FTI (0.83%), ATI (0.80%).
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 | IVV | MDY |
|---|---|---|
| 2022 | -18.2% | -13.3% |
| 2023 | +26.3% | +16.1% |
| 2024 | +24.9% | +13.6% |
| 2025 | +17.8% | +7.2% |
| 2026 | +13.7% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are IVV and MDY good diversifiers for each other?
No: a correlation of 0.80 means IVV and MDY tend to fall together, which is precisely when diversification is supposed to help.
FAQ
What is the correlation between IVV and MDY?
The IVV/MDY correlation stands at 0.80 on a 3-year window (1 year: 0.65, 5 years: 0.86), computed from weekly returns as of 2026-08-27.
Is MDY a good diversifier for IVV?
No: a correlation of 0.80 means IVV and MDY tend to fall together, which is precisely when diversification is supposed to help.
How much do IVV and MDY overlap?
The two funds share 0 holdings amounting to 0% of weight, per issuer portfolio files dated 2026-08-26.
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Related comparisons
Hubs: IVV correlations · MDY correlations
