PBYI vs SPY: Correlation
How closely do Puma Biotechnology Inc (PBYI) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.19, which is weak.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PBYI and SPY?
Over the past 3 years, PBYI and SPY moved with a correlation of 0.19, which is weak. Recent behaviour matches the longer record: 0.10 over 1 year against 0.19 over 3. Over 5 years the correlation is 0.20, and the annualized covariance of weekly returns is 190.3 %².
SPY is close to the least connected end of PBYI's tracked universe, ranking #6 of 10. Their recent paths diverged sharply: over the last 12 months PBYI outperformed by 60.6 percentage points (+81.2% for PBYI against +20.6% for SPY). One caveat on sizing: PBYI is 4.9 times as volatile as the other leg, so an equal-dollar split is far from equal-risk.
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.
PBYI vs SPY: side by side
| PBYI (Puma Biotechnology Inc) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +81.2% | +20.6% |
| 5-year return | +21.4% | +82.4% |
| Volatility (ann.) | 70.9% | 14.5% |
| Beta vs S&P 500 | 0.91 | 1.00 |
| Max drawdown (3Y) | -69.6% | -18.8% |
| Market cap | $0.5B | – |
| P/E (trailing) | 18.1 | – |
| 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 | PBYI | SPY |
|---|---|---|
| 2022 | +39.1% | -18.2% |
| 2023 | +2.4% | +26.2% |
| 2024 | -29.6% | +24.9% |
| 2025 | +95.1% | +17.7% |
| 2026 | +55.3% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PBYI and SPY good diversifiers for each other?
Yes. With a correlation of 0.19, PBYI and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
FAQ
What is the correlation between PBYI and SPY?
Using weekly returns as of 2026-08-27: 0.19 over 3 years, with 0.10 over the last year and 0.20 over 5 years.
Is SPY a good diversifier for PBYI?
Yes. With a correlation of 0.19, PBYI and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
What does a correlation of 0.19 mean?
A reading of 0.19 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: PBYI correlations · SPY correlations
