RARE vs SPY: Correlation
How closely do Ultragenyx Pharmaceutical Inc. (RARE) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.39, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are RARE and SPY?
Across a 3-year window, the weekly returns of RARE and SPY correlate at 0.39, moderate. Little has changed lately, as the 1-year reading of 0.42 lands near the 3-year figure. Stretching to 5 years gives 0.35, with an annualized covariance of 288.1 %².
Among the 14 assets we track against RARE, SPY ranks #8 by 3-year correlation. The last year tells two different stories: SPY led by 33.3 percentage points, -12.7% for RARE against +20.6% for SPY. Risk is not evenly split, since RARE carries 3.5 times the volatility of the other side.
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.
RARE vs SPY: side by side
| RARE (Ultragenyx Pharmaceutical Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -12.7% | +20.6% |
| 5-year return | -72.6% | +82.4% |
| Volatility (ann.) | 51.1% | 14.5% |
| Beta vs S&P 500 | 1.38 | 1.00 |
| Max drawdown (3Y) | -68.8% | -18.8% |
| Market cap | $2.6B | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | US Listed | ETF · US Large Cap |
SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | RARE | SPY |
|---|---|---|
| 2022 | -44.9% | -18.2% |
| 2023 | +3.2% | +26.2% |
| 2024 | -12.0% | +24.9% |
| 2025 | -45.3% | +17.7% |
| 2026 | +14.2% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are RARE and SPY good diversifiers for each other?
A fair diversifier. At 0.39, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between RARE and SPY?
The RARE/SPY correlation stands at 0.39 on a 3-year window (1 year: 0.42, 5 years: 0.35), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for RARE?
A fair diversifier. At 0.39, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.39 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: RARE correlations · SPY correlations
