MDY vs SPYG: Correlation & Overlap
How closely do SPDR S&P MidCap 400 ETF (MDY) and SPDR Portfolio S&P 500 Growth ETF (SPYG) trade together? Their weekly returns over three years give a correlation of 0.66, 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 SPYG?
On 3 years of weekly data the MDY/SPYG correlation comes out at 0.66, strong. The past 12 months show a weaker link (0.51) than the 3-year average (0.66). The 5-year figure is 0.74, and annualized covariance runs at 204.8 %².
By 3-year correlation, SPYG places #103 of the 359 assets tracked against MDY. Twelve-month performance is nearly a tie, at +18.3% for MDY and +22.4% for SPYG. Across three years, the rolling one-year figure varied moderately, from 0.47 to 0.84.
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 SPYG: side by side
| MDY (SPDR S&P MidCap 400 ETF) | SPYG (SPDR Portfolio S&P 500 Growth ETF) | |
|---|---|---|
| 1-year return | +18.3% | +22.4% |
| 5-year return | +47.5% | +85.9% |
| Volatility (ann.) | 16.5% | 18.9% |
| Beta vs S&P 500 | 0.91 | 1.25 |
| Max drawdown (3Y) | -24.0% | -22.1% |
| Dividend yield | 1.02% | 0.49% |
| Expense ratio | 0.23% | 0.04% |
| Assets under management | $26.5B | $52.2B |
| Sector / category | ETF · US Small & Mid Cap | ETF · US Style |
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. SPYG is a Large Growth fund from State Street Investment Management: $52.2B under management, 148 holdings, a 0.04% expense ratio, a 0.49% trailing dividend yield.
Portfolio overlap between MDY and SPYG
The two portfolios are largely distinct. Weighing the shared positions, 0% of the two funds is identical, spread across 0 common holdings. That shared book is a large part of why the returns line up.
Largest positions held only by MDY: TWLO (0.95%), P (0.94%), ILMN (0.93%), FTI (0.83%), ATI (0.80%). Only by SPYG: NVDA (14.21%), MSFT (10.32%), AAPL (6.44%), GOOGL (5.61%), AVGO (4.71%).
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 | SPYG |
|---|---|---|
| 2022 | -13.3% | -29.4% |
| 2023 | +16.1% | +30.0% |
| 2024 | +13.6% | +36.0% |
| 2025 | +7.2% | +22.1% |
| 2026 | +16.4% | +14.5% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MDY and SPYG good diversifiers for each other?
To a limited degree. At 0.66 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
FAQ
What is the correlation between MDY and SPYG?
Using weekly returns as of 2026-08-27: 0.66 over 3 years, with 0.51 over the last year and 0.74 over 5 years.
Is SPYG a good diversifier for MDY?
To a limited degree. At 0.66 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
How much do MDY and SPYG 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-spyg.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/mdy-vs-spyg/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: MDY correlations · SPYG correlations
