PESI vs SPY: Correlation
Measured on weekly returns over the past three years, Perma-Fix Environmental Services, Inc. (PESI) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.27, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PESI and SPY?
Over the past 3 years, PESI and SPY moved with a correlation of 0.27, which is weak. Recent behaviour matches the longer record: 0.20 over 1 year against 0.27 over 3. Over 5 years the correlation is 0.18, and the annualized covariance of weekly returns is 230.8 %².
Out of 10 assets tracked against PESI, SPY lands near the bottom at #6. Their recent paths diverged sharply: over the last 12 months PESI outperformed by 40.8 percentage points (+61.4% for PESI against +20.6% for SPY). One caveat on sizing: PESI is 4.1 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.
PESI vs SPY: side by side
| PESI (Perma-Fix Environmental Services, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +61.4% | +20.6% |
| 5-year return | +234.5% | +82.4% |
| Volatility (ann.) | 59.3% | 14.5% |
| Beta vs S&P 500 | 1.10 | 1.00 |
| Max drawdown (3Y) | -58.0% | -18.8% |
| Market cap | $0.4B | – |
| 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 | PESI | SPY |
|---|---|---|
| 2022 | -44.2% | -18.2% |
| 2023 | +122.7% | +26.2% |
| 2024 | +40.8% | +24.9% |
| 2025 | +13.7% | +17.7% |
| 2026 | +53.3% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PESI and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.27 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between PESI and SPY?
Using weekly returns as of 2026-08-27: 0.27 over 3 years, with 0.20 over the last year and 0.18 over 5 years.
Is SPY a good diversifier for PESI?
Yes, to a useful degree: a correlation of 0.27 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.27 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: PESI correlations · SPY correlations
