MDY vs VWO: Correlation & Overlap
SPDR S&P MidCap 400 ETF (MDY) and Vanguard FTSE Emerging Markets ETF (VWO) show a strong relationship: their 3-year correlation of weekly returns is 0.62. The two funds also share 0.5% of their portfolios by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MDY and VWO?
Over the past 3 years, MDY and VWO moved with a correlation of 0.62, which is strong. Little has changed lately, as the 1-year reading of 0.69 lands near the 3-year figure. Over 5 years the correlation is 0.61, and the annualized covariance of weekly returns is 155.3 %².
Within MDY's tracked universe of 359 assets, VWO comes in at #157 by 3-year correlation. Their 12-month results are close: +18.3% for MDY against +21.6% for VWO. Across three years, the rolling one-year figure varied moderately, from 0.39 to 0.79.
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 VWO: side by side
| MDY (SPDR S&P MidCap 400 ETF) | VWO (Vanguard FTSE Emerging Markets ETF) | |
|---|---|---|
| 1-year return | +18.3% | +21.6% |
| 5-year return | +47.5% | +38.2% |
| Volatility (ann.) | 16.5% | 15.2% |
| Beta vs S&P 500 | 0.91 | 0.75 |
| Max drawdown (3Y) | -24.0% | -17.4% |
| Dividend yield | 1.02% | 2.36% |
| Expense ratio | 0.23% | 0.06% |
| Assets under management | $26.5B | $162.0B |
| Sector / category | ETF · US Small & Mid Cap | ETF · International |
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. On the fund side, VWO sits in the Diversified Emerging Mkts category at Vanguard, with $162.0B under management, 4113 holdings, a 0.06% expense ratio, a 2.36% trailing dividend yield.
Portfolio overlap between MDY and VWO
The two portfolios are largely distinct. Weighing the shared positions, 0.5% of the two funds is identical, spread across 11 common holdings. That shared book is a large part of why the returns line up.
| Common holding | Weight in MDY | Weight in VWO |
|---|---|---|
| VAL | 0.15% | 0.21% |
| MTN | 0.15% | 0.22% |
| SLM | 0.14% | 0.09% |
| MOH | 0.29% | 0.04% |
| PPC | 0.04% | 0.08% |
| TRU | 0.45% | 0.01% |
| M | 0.16% | 0.01% |
| SCI | 0.32% | 0.01% |
| SUI | 0.40% | 0.00% |
| RBA | 0.44% | 0.00% |
| ACI | 0.12% | 0.00% |
Largest positions held only by MDY: TWLO (0.95%), P (0.94%), ILMN (0.93%), FTI (0.83%), ATI (0.80%). Only by VWO: 2330 (18.65%), 700 (3.97%), 9988 (2.90%), 2454 (1.62%), 939 (1.07%).
Overlap = sum of the smaller of the two weights across common holdings, from issuer disclosures as of 2026-08-26. Top 11 common positions shown.
Year-by-year returns
| Year | MDY | VWO |
|---|---|---|
| 2022 | -13.3% | -18.0% |
| 2023 | +16.1% | +9.3% |
| 2024 | +13.6% | +10.6% |
| 2025 | +7.2% | +25.6% |
| 2026 | +16.4% | +13.6% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and VWO good diversifiers for each other?
Only partially. A correlation of 0.62 means MDY and VWO share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
FAQ
What is the correlation between MDY and VWO?
The MDY/VWO correlation stands at 0.62 on a 3-year window (1 year: 0.69, 5 years: 0.61), computed from weekly returns as of 2026-08-27.
Is VWO a good diversifier for MDY?
Only partially. A correlation of 0.62 means MDY and VWO share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
How much do MDY and VWO overlap?
Per the issuers' own portfolio disclosures (2026-08-26), the overlap is 0.5% by weight over 11 common positions.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/mdy-vs-vwo.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/mdy-vs-vwo/)
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Hubs: MDY correlations · VWO correlations
