ALGN vs MDY: Correlation
How closely do Align Technology (ALGN) and SPDR S&P MidCap 400 ETF (MDY) trade together? Their weekly returns over three years give a correlation of 0.57, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ALGN and MDY?
On 3 years of weekly data the ALGN/MDY correlation comes out at 0.57, moderate. The relationship has been stable: the 1-year correlation (0.66) sits close to the 3-year figure. The 5-year figure is 0.60, and annualized covariance runs at 415.4 %².
Within ALGN's tracked universe of 37 assets, MDY comes in at #4 by 3-year correlation. On 12-month performance MDY holds a 6.4-point edge, +11.9% against +18.3%. The rolling one-year correlation moved between 0.38 and 0.66 over the past three years, a moderate range. Note the risk asymmetry: ALGN runs 2.7 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
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.
ALGN vs MDY: side by side
| ALGN (Align Technology) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +11.9% | +18.3% |
| 5-year return | -77.4% | +47.5% |
| Volatility (ann.) | 44.3% | 16.5% |
| Beta vs S&P 500 | 1.51 | 0.91 |
| Max drawdown (3Y) | -66.7% | -24.0% |
| Market cap | $11.3B | – |
| P/E (trailing) | 27.6 | – |
| Dividend yield | 0.00% | 1.02% |
| Expense ratio | – | 0.23% |
| Assets under management | – | $26.5B |
| Sector / category | Health Care | ETF · US Small & Mid Cap |
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.
Year-by-year returns
| Year | ALGN | MDY |
|---|---|---|
| 2022 | -67.9% | -13.3% |
| 2023 | +29.9% | +16.1% |
| 2024 | -23.9% | +13.6% |
| 2025 | -25.1% | +7.2% |
| 2026 | +1.7% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are ALGN and MDY good diversifiers for each other?
Only partially. A correlation of 0.57 means ALGN and MDY 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 ALGN and MDY?
The ALGN/MDY correlation stands at 0.57 on a 3-year window (1 year: 0.66, 5 years: 0.60), computed from weekly returns as of 2026-08-27.
Is MDY a good diversifier for ALGN?
Only partially. A correlation of 0.57 means ALGN and MDY share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
What does a correlation of 0.57 mean?
Correlation ranges from −1 to +1. Values near +1 mean two assets move together, near 0 that they move independently, and negative values that they tend to move in opposite directions. It measures co-movement, not performance.
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Related comparisons
Hubs: ALGN correlations · MDY correlations
