PDFS vs SPY: Correlation
How closely do PDF Solutions, Inc. (PDFS) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.47, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PDFS and SPY?
Over the past 3 years, PDFS and SPY moved with a correlation of 0.47, which is moderate. The link has loosened recently: the 1-year correlation (0.32) runs below the 3-year figure (0.47). Over 5 years the correlation is 0.49, and the annualized covariance of weekly returns is 323.7 %².
Among the 16 assets we track against PDFS, SPY ranks #11 by 3-year correlation. Correlation aside, the last 12 months split them widely, with PDFS ahead by 113.0 points (+133.6% versus +20.6%). One caveat on sizing: PDFS is 3.3 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.
PDFS vs SPY: side by side
| PDFS (PDF Solutions, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +133.6% | +20.6% |
| 5-year return | +105.9% | +82.4% |
| Volatility (ann.) | 47.4% | 14.5% |
| Beta vs S&P 500 | 1.55 | 1.00 |
| Max drawdown (3Y) | -58.5% | -18.8% |
| Market cap | $1.9B | – |
| P/E (trailing) | 177.5 | – |
| 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 | PDFS | SPY |
|---|---|---|
| 2022 | -10.3% | -18.2% |
| 2023 | +12.7% | +26.2% |
| 2024 | -15.7% | +24.9% |
| 2025 | +5.4% | +17.7% |
| 2026 | +61.8% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PDFS and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.47 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between PDFS and SPY?
As of 2026-08-27, the correlation of weekly returns between PDFS and SPY is 0.47 over 3 years, 0.32 over 1 year and 0.49 over 5 years.
Is SPY a good diversifier for PDFS?
Yes, to a useful degree: a correlation of 0.47 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.47 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: PDFS correlations · SPY correlations
