NGS vs NPKI: Correlation
Natural Gas Services Group, Inc. (NGS) and NPK International Inc. (NPKI) show a moderate relationship: their 3-year correlation of weekly returns is 0.52.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are NGS and NPKI?
Over the past 3 years, NGS and NPKI moved with a correlation of 0.52, which is moderate. Little has changed lately, as the 1-year reading of 0.45 lands near the 3-year figure. Over 5 years the correlation is 0.49, and the annualized covariance of weekly returns is 958.0 %².
Within NGS's tracked universe of 13 assets, NPKI comes in at #6 by 3-year correlation. Over the last 12 months NGS came out ahead by 6.3 percentage points (+37.9% against +31.6%).
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 NPKI: side by side
| NGS (Natural Gas Services Group, Inc.) | NPKI (NPK International Inc.) | |
|---|---|---|
| 1-year return | +37.9% | +31.6% |
| 5-year return | +274.7% | +429.3% |
| Volatility (ann.) | 45.0% | 41.0% |
| Beta vs S&P 500 | 0.87 | 0.88 |
| Max drawdown (3Y) | -40.9% | -42.1% |
| Market cap | $0.5B | $1.2B |
| P/E (trailing) | 21.7 | 28.8 |
| Dividend yield | 1.35% | 0.00% |
| Sector / category | US Listed | US Listed |
Year-by-year returns
| Year | NGS | NPKI |
|---|---|---|
| 2022 | +9.5% | +41.2% |
| 2023 | +40.3% | +60.0% |
| 2024 | +66.7% | +15.5% |
| 2025 | +26.5% | +55.4% |
| 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 NPKI good diversifiers for each other?
To a limited degree. At 0.52 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
FAQ
What is the correlation between NGS and NPKI?
As of 2026-08-27, the correlation of weekly returns between NGS and NPKI is 0.52 over 3 years, 0.45 over 1 year and 0.49 over 5 years.
Is NPKI a good diversifier for NGS?
To a limited degree. At 0.52 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
What does a correlation of 0.52 mean?
On the −1 to +1 scale, 0.52 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/ngs-vs-npki.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/ngs-vs-npki/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: NGS correlations · NPKI correlations
