RGEN vs WST: Correlation
How closely do Repligen Corporation (RGEN) and West Pharmaceutical Services (WST) 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 RGEN and WST?
Over the past 3 years, RGEN and WST moved with a correlation of 0.37, which is moderate. Recent behaviour matches the longer record: 0.46 over 1 year against 0.37 over 3. Over 5 years the correlation is 0.49, and the annualized covariance of weekly returns is 714.4 %².
Within RGEN's tracked universe of 17 assets, WST comes in at #12 by 3-year correlation. The trailing year gives RGEN the advantage: +53.1% versus +41.1%, a 12.0-point spread.
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.
RGEN vs WST: side by side
| RGEN (Repligen Corporation) | WST (West Pharmaceutical Services) | |
|---|---|---|
| 1-year return | +53.1% | +41.1% |
| 5-year return | -35.6% | -22.4% |
| Volatility (ann.) | 49.5% | 38.6% |
| Beta vs S&P 500 | 1.35 | 0.86 |
| Max drawdown (3Y) | -50.6% | -53.8% |
| Market cap | $10.3B | $24.4B |
| P/E (trailing) | 252.8 | 44.8 |
| Dividend yield | 0.00% | 0.25% |
| Sector / category | US Listed | Health Care |
Year-by-year returns
| Year | RGEN | WST |
|---|---|---|
| 2022 | -36.1% | -49.7% |
| 2023 | +6.2% | +50.0% |
| 2024 | -19.9% | -6.8% |
| 2025 | +13.8% | -15.7% |
| 2026 | +11.1% | +26.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are RGEN and WST good diversifiers for each other?
Reasonably. At 0.37, RGEN and WST keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between RGEN and WST?
As of 2026-08-27, the correlation of weekly returns between RGEN and WST is 0.37 over 3 years, 0.46 over 1 year and 0.49 over 5 years.
Is WST a good diversifier for RGEN?
Reasonably. At 0.37, RGEN and WST 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/rgen-vs-wst.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/rgen-vs-wst/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: RGEN correlations · WST correlations
