ACHC vs ISBA: Correlation
Acadia Healthcare Company, Inc. (ACHC) and Isabella Bank Corporation (ISBA) show a negative relationship: their 3-year correlation of weekly returns is -0.20.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ACHC and ISBA?
Over the past 3 years, ACHC and ISBA moved with a correlation of -0.20, which is negative, meaning they tend to move in opposite directions. The relationship has been stable: the 1-year correlation (-0.29) sits close to the 3-year figure. Over 5 years the correlation is -0.17, and the annualized covariance of weekly returns is -390.2 %².
Out of 10 assets tracked against ACHC, ISBA lands near the bottom at #10. Correlation aside, the last 12 months split them widely, with ACHC ahead by 19.8 points (+36.2% versus +16.4%). One caveat on sizing: ACHC is 1.8 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.
ACHC vs ISBA: side by side
| ACHC (Acadia Healthcare Company, Inc.) | ISBA (Isabella Bank Corporation) | |
|---|---|---|
| 1-year return | +36.2% | +16.4% |
| 5-year return | -54.4% | +104.9% |
| Volatility (ann.) | 58.4% | 33.3% |
| Beta vs S&P 500 | 0.62 | 0.05 |
| Max drawdown (3Y) | -86.6% | -34.1% |
| Market cap | $2.8B | $0.3B |
| P/E (trailing) | – | 14.2 |
| Dividend yield | 0.00% | 2.91% |
| Sector / category | US Listed | US Listed |
Year-by-year returns
| Year | ACHC | ISBA |
|---|---|---|
| 2022 | +35.6% | -3.5% |
| 2023 | -5.5% | -3.5% |
| 2024 | -49.0% | +27.7% |
| 2025 | -64.2% | +99.1% |
| 2026 | +113.0% | -21.9% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are ACHC and ISBA good diversifiers for each other?
Yes: at -0.20, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between ACHC and ISBA?
The ACHC/ISBA correlation stands at -0.20 on a 3-year window (1 year: -0.29, 5 years: -0.17), computed from weekly returns as of 2026-08-27.
Is ISBA a good diversifier for ACHC?
Yes: at -0.20, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of -0.20 mean?
On the −1 to +1 scale, -0.20 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/achc-vs-isba.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/achc-vs-isba/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: ACHC correlations · ISBA correlations
