BIIB vs MRK: Correlation
Measured on weekly returns over the past three years, Biogen (BIIB) and Merck & Co. (MRK) carry a correlation of 0.52, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BIIB and MRK?
On 3 years of weekly data the BIIB/MRK correlation comes out at 0.52, moderate. The relationship has been stable: the 1-year correlation (0.62) sits close to the 3-year figure. The 5-year figure is 0.39, and annualized covariance runs at 438.9 %².
Among the 32 assets we track against BIIB, MRK ranks #4 by 3-year correlation. Their recent paths diverged sharply: over the last 12 months MRK outperformed by 21.4 percentage points (+62.4% for BIIB against +83.8% for MRK). This link changes with the market regime, having swung between 0.09 and 0.73 on a rolling one-year basis.
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.
BIIB vs MRK: side by side
| BIIB (Biogen) | MRK (Merck & Co.) | |
|---|---|---|
| 1-year return | +62.4% | +83.8% |
| 5-year return | -35.7% | +128.5% |
| Volatility (ann.) | 30.1% | 27.9% |
| Beta vs S&P 500 | 0.53 | 0.28 |
| Max drawdown (3Y) | -57.7% | -43.4% |
| Market cap | $32.7B | $368.9B |
| P/E (trailing) | 39.2 | 121.6 |
| Dividend yield | 0.00% | 2.17% |
| Sector / category | Health Care | Health Care |
Year-by-year returns
| Year | BIIB | MRK |
|---|---|---|
| 2022 | +15.4% | +49.4% |
| 2023 | -6.6% | +1.0% |
| 2024 | -40.9% | -6.3% |
| 2025 | +15.1% | +9.8% |
| 2026 | +25.9% | +44.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BIIB and MRK good diversifiers for each other?
To a limited degree. At 0.52 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
FAQ
What is the correlation between BIIB and MRK?
Using weekly returns as of 2026-08-27: 0.52 over 3 years, with 0.62 over the last year and 0.39 over 5 years.
Is MRK a good diversifier for BIIB?
To a limited degree. At 0.52 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
What does a correlation of 0.52 mean?
Correlation ranges from −1 to +1. Values near +1 mean two assets move together, near 0 that they move independently, and negative values that they tend to move in opposite directions. It measures co-movement, not performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/biib-vs-mrk.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/biib-vs-mrk/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: BIIB correlations · MRK correlations
