PDEX vs SPY: Correlation
Pro-Dex, Inc. (PDEX) and SPDR S&P 500 ETF Trust (SPY) show a near-zero relationship: their 3-year correlation of weekly returns is 0.04.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PDEX and SPY?
On 3 years of weekly data the PDEX/SPY correlation comes out at 0.04, near zero, meaning they move largely independently. The past 12 months show a tighter link (0.25) than the 3-year average (0.04). The 5-year figure is 0.08, and annualized covariance runs at 35.6 %².
Within PDEX's tracked universe of 31 assets, SPY comes in at #7 by 3-year correlation. The last year tells two different stories: PDEX led by 21.9 percentage points, +42.5% for PDEX against +20.6% for SPY. Risk is not evenly split, since PDEX carries 4.1 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.
PDEX vs SPY: side by side
| PDEX (Pro-Dex, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +42.5% | +20.6% |
| 5-year return | +152.4% | +82.4% |
| Volatility (ann.) | 59.6% | 14.5% |
| Beta vs S&P 500 | 0.17 | 1.00 |
| Max drawdown (3Y) | -65.3% | -18.8% |
| Market cap | $0.2B | – |
| P/E (trailing) | 17.5 | – |
| 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 | PDEX | SPY |
|---|---|---|
| 2022 | -31.5% | -18.2% |
| 2023 | +10.2% | +26.2% |
| 2024 | +166.8% | +24.9% |
| 2025 | -17.7% | +17.7% |
| 2026 | +68.6% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PDEX and SPY good diversifiers for each other?
Yes: at 0.04, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between PDEX and SPY?
The PDEX/SPY correlation stands at 0.04 on a 3-year window (1 year: 0.25, 5 years: 0.08), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for PDEX?
Yes: at 0.04, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of 0.04 mean?
On the −1 to +1 scale, 0.04 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: PDEX correlations · SPY correlations
