CSTL vs RAY: Correlation
Measured on weekly returns over the past three years, Castle Biosciences, Inc. (CSTL) and Raytech Holding Limited (RAY) carry a correlation of -0.20, a negative link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CSTL and RAY?
Across a 3-year window, the weekly returns of CSTL and RAY correlate at -0.20, negative, meaning they tend to move in opposite directions. Little has changed lately, as the 1-year reading of -0.20 lands near the 3-year figure. Stretching to 5 years gives n/a, with an annualized covariance of -1802.2 %².
Among the 12 assets we track against CSTL, RAY sits near the bottom by co-movement, at rank #10. Correlation aside, the last 12 months split them widely, with CSTL ahead by 137.8 points (+53.8% versus -84.0%). Note the risk asymmetry: RAY runs 2.3 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
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.
CSTL vs RAY: side by side
| CSTL (Castle Biosciences, Inc.) | RAY (Raytech Holding Limited) | |
|---|---|---|
| 1-year return | +53.8% | -84.0% |
| 5-year return | -54.0% | n/a |
| Volatility (ann.) | 64.2% | 146.1% |
| Beta vs S&P 500 | 0.79 | 0.37 |
| Max drawdown (3Y) | -57.8% | -97.7% |
| Market cap | $1.0B | – |
| P/E (trailing) | – | 3.0 |
| Dividend yield | 0.00% | 0.00% |
| Sector / category | US Listed | US Listed |
Year-by-year returns
| Year | CSTL | RAY |
|---|---|---|
| 2022 | -45.1% | – |
| 2023 | -8.3% | – |
| 2024 | +23.5% | – |
| 2025 | +46.0% | -90.5% |
| 2026 | -11.9% | +36.0% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are CSTL and RAY good diversifiers for each other?
By historical standards, yes. A correlation of -0.20 means the two rarely move for the same reasons.
FAQ
What is the correlation between CSTL and RAY?
Using weekly returns as of 2026-08-27: -0.20 over 3 years, with -0.20 over the last year and n/a over 5 years.
Is RAY a good diversifier for CSTL?
By historical standards, yes. A correlation of -0.20 means the two rarely move for the same reasons.
What does a correlation of -0.20 mean?
A reading of -0.20 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/cstl-vs-ray.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/cstl-vs-ray/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: CSTL correlations · RAY correlations
