PTGX vs SPY: Correlation
Measured on weekly returns over the past three years, Protagonist Therapeutics, Inc. (PTGX) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.13, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PTGX and SPY?
On 3 years of weekly data the PTGX/SPY correlation comes out at 0.13, weak. The past 12 months show a weaker link (-0.17) than the 3-year average (0.13). The 5-year figure is 0.19, and annualized covariance runs at 101.9 %².
SPY is close to the least connected end of PTGX's tracked universe, ranking #7 of 11. Their recent paths diverged sharply: over the last 12 months PTGX outperformed by 122.8 percentage points (+143.4% for PTGX against +20.6% for SPY). Risk is not evenly split, since PTGX carries 3.7 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.
PTGX vs SPY: side by side
| PTGX (Protagonist Therapeutics, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +143.4% | +20.6% |
| 5-year return | +219.7% | +82.4% |
| Volatility (ann.) | 53.0% | 14.5% |
| Beta vs S&P 500 | 0.49 | 1.00 |
| Max drawdown (3Y) | -31.6% | -18.8% |
| Market cap | $9.7B | – |
| P/E (trailing) | 145.1 | – |
| 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 | PTGX | SPY |
|---|---|---|
| 2022 | -68.1% | -18.2% |
| 2023 | +110.2% | +26.2% |
| 2024 | +68.3% | +24.9% |
| 2025 | +126.3% | +17.7% |
| 2026 | +71.2% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PTGX and SPY good diversifiers for each other?
Yes: at 0.13, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between PTGX and SPY?
As of 2026-08-27, the correlation of weekly returns between PTGX and SPY is 0.13 over 3 years, -0.17 over 1 year and 0.19 over 5 years.
Is SPY a good diversifier for PTGX?
Yes: at 0.13, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of 0.13 mean?
On the −1 to +1 scale, 0.13 describes how much the two returns move together: +1 is lockstep, 0 is independence, negative values mean opposite directions. It says nothing about which performed better.
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Related comparisons
Hubs: PTGX correlations · SPY correlations
