CSTL vs TARS: Correlation
How closely do Castle Biosciences, Inc. (CSTL) and Tarsus Pharmaceuticals, Inc. (TARS) trade together? Their weekly returns over three years give a correlation of 0.37, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CSTL and TARS?
Over the past 3 years, CSTL and TARS moved with a correlation of 0.37, which is moderate. The past 12 months show a weaker link (0.15) than the 3-year average (0.37). Over 5 years the correlation is 0.25, and the annualized covariance of weekly returns is 1251.5 %².
Among the 12 assets we track against CSTL, TARS ranks #7 by 3-year correlation. The last year tells two different stories: CSTL led by 29.4 percentage points, +53.8% for CSTL against +24.4% for TARS.
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 TARS: side by side
| CSTL (Castle Biosciences, Inc.) | TARS (Tarsus Pharmaceuticals, Inc.) | |
|---|---|---|
| 1-year return | +53.8% | +24.4% |
| 5-year return | -54.0% | +171.4% |
| Volatility (ann.) | 64.2% | 53.2% |
| Beta vs S&P 500 | 0.79 | 0.51 |
| Max drawdown (3Y) | -57.8% | -45.1% |
| Market cap | $1.0B | $3.2B |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 0.00% |
| Sector / category | US Listed | US Listed |
Year-by-year returns
| Year | CSTL | TARS |
|---|---|---|
| 2022 | -45.1% | -34.8% |
| 2023 | -8.3% | +38.1% |
| 2024 | +23.5% | +173.4% |
| 2025 | +46.0% | +47.9% |
| 2026 | -11.9% | -12.2% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are CSTL and TARS good diversifiers for each other?
Reasonably. At 0.37, CSTL and TARS keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between CSTL and TARS?
Using weekly returns as of 2026-08-27: 0.37 over 3 years, with 0.15 over the last year and 0.25 over 5 years.
Is TARS a good diversifier for CSTL?
Reasonably. At 0.37, CSTL and TARS keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.37 mean?
A reading of 0.37 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-tars.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/cstl-vs-tars/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: CSTL correlations · TARS correlations
