NGS vs SPY: Correlation
Natural Gas Services Group, Inc. (NGS) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.28.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are NGS and SPY?
Over the past 3 years, NGS and SPY moved with a correlation of 0.28, which is weak. The link has loosened recently: the 1-year correlation (-0.12) runs below the 3-year figure (0.28). Over 5 years the correlation is 0.22, and the annualized covariance of weekly returns is 182.7 %².
Among the 13 assets we track against NGS, SPY sits near the bottom by co-movement, at rank #9. The last year tells two different stories: NGS led by 17.3 percentage points, +37.9% for NGS against +20.6% for SPY. One caveat on sizing: NGS is 3.1 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.
NGS vs SPY: side by side
| NGS (Natural Gas Services Group, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +37.9% | +20.6% |
| 5-year return | +274.7% | +82.4% |
| Volatility (ann.) | 45.0% | 14.5% |
| Beta vs S&P 500 | 0.87 | 1.00 |
| Max drawdown (3Y) | -40.9% | -18.8% |
| Market cap | $0.5B | – |
| P/E (trailing) | 21.7 | – |
| Dividend yield | 1.35% | 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 | NGS | SPY |
|---|---|---|
| 2022 | +9.5% | -18.2% |
| 2023 | +40.3% | +26.2% |
| 2024 | +66.7% | +24.9% |
| 2025 | +26.5% | +17.7% |
| 2026 | +6.3% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are NGS and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.28 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between NGS and SPY?
The NGS/SPY correlation stands at 0.28 on a 3-year window (1 year: -0.12, 5 years: 0.22), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for NGS?
Yes, to a useful degree: a correlation of 0.28 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.28 mean?
On the −1 to +1 scale, 0.28 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: NGS correlations · SPY correlations
