PEN vs SPY: Correlation
Penumbra, Inc. (PEN) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.12.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PEN and SPY?
Across a 3-year window, the weekly returns of PEN and SPY correlate at 0.12, weak. The past 12 months show a weaker link (-0.17) than the 3-year average (0.12). Stretching to 5 years gives 0.35, with an annualized covariance of 63.6 %².
By 3-year correlation, SPY places #7 of the 12 assets tracked against PEN. Twelve-month performance is nearly a tie, at +20.3% for PEN and +20.6% for SPY. One caveat on sizing: PEN is 2.5 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.
PEN vs SPY: side by side
| PEN (Penumbra, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +20.3% | +20.6% |
| 5-year return | +18.7% | +82.4% |
| Volatility (ann.) | 36.0% | 14.5% |
| Beta vs S&P 500 | 0.30 | 1.00 |
| Max drawdown (3Y) | -45.5% | -18.8% |
| Market cap | $12.6B | – |
| P/E (trailing) | 79.5 | – |
| 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 | PEN | SPY |
|---|---|---|
| 2022 | -22.6% | -18.2% |
| 2023 | +13.1% | +26.2% |
| 2024 | -5.6% | +24.9% |
| 2025 | +30.9% | +17.7% |
| 2026 | +3.2% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PEN and SPY good diversifiers for each other?
Yes: at 0.12, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between PEN and SPY?
As of 2026-08-27, the correlation of weekly returns between PEN and SPY is 0.12 over 3 years, -0.17 over 1 year and 0.35 over 5 years.
Is SPY a good diversifier for PEN?
Yes: at 0.12, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of 0.12 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/pen-vs-spy.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/pen-vs-spy/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: PEN correlations · SPY correlations
