WST vs XLO: Correlation
West Pharmaceutical Services (WST) and Xilio Therapeutics, Inc. (XLO) show a negative relationship: their 3-year correlation of weekly returns is -0.22.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are WST and XLO?
Across a 3-year window, the weekly returns of WST and XLO correlate at -0.22, negative, meaning they tend to move in opposite directions. The link has tightened recently: the 1-year correlation (0.14) runs above the 3-year figure (-0.22). Stretching to 5 years gives -0.02, with an annualized covariance of -826.0 %².
Within WST's tracked universe of 36 assets, XLO comes in at #25 by 3-year correlation. The last year tells two different stories: WST led by 47.1 percentage points, +41.1% for WST against -6.0% for XLO. Risk is not evenly split, since XLO carries 2.5 times the volatility of the other side.
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.
WST vs XLO: side by side
| WST (West Pharmaceutical Services) | XLO (Xilio Therapeutics, Inc.) | |
|---|---|---|
| 1-year return | +41.1% | -6.0% |
| 5-year return | -22.4% | -96.0% |
| Volatility (ann.) | 38.6% | 96.4% |
| Beta vs S&P 500 | 0.86 | -0.07 |
| Max drawdown (3Y) | -53.8% | -82.8% |
| Market cap | $24.4B | $0.1B |
| P/E (trailing) | 44.8 | – |
| Dividend yield | 0.25% | 0.00% |
| Sector / category | Health Care | US Listed |
Year-by-year returns
| Year | WST | XLO |
|---|---|---|
| 2022 | -49.7% | -83.2% |
| 2023 | +50.0% | -79.6% |
| 2024 | -6.8% | +73.6% |
| 2025 | -15.7% | -33.0% |
| 2026 | +26.1% | +0.6% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are WST and XLO good diversifiers for each other?
Yes. With a correlation of -0.22, WST and XLO have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
FAQ
What is the correlation between WST and XLO?
Using weekly returns as of 2026-08-27: -0.22 over 3 years, with 0.14 over the last year and -0.02 over 5 years.
Is XLO a good diversifier for WST?
Yes. With a correlation of -0.22, WST and XLO have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
What does a correlation of -0.22 mean?
A reading of -0.22 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/wst-vs-xlo.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/wst-vs-xlo/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: WST correlations · XLO correlations
