BIIB vs IONS: Correlation
Measured on weekly returns over the past three years, Biogen (BIIB) and Ionis Pharmaceuticals, Inc. (IONS) carry a correlation of 0.47, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BIIB and IONS?
On 3 years of weekly data the BIIB/IONS correlation comes out at 0.47, moderate. The relationship has been stable: the 1-year correlation (0.44) sits close to the 3-year figure. The 5-year figure is 0.43, and annualized covariance runs at 627.2 %².
By 3-year correlation, IONS places #12 of the 32 assets tracked against BIIB. Correlation aside, the last 12 months split them widely, with BIIB ahead by 16.4 points (+62.4% versus +46.0%).
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 IONS: side by side
| BIIB (Biogen) | IONS (Ionis Pharmaceuticals, Inc.) | |
|---|---|---|
| 1-year return | +62.4% | +46.0% |
| 5-year return | -35.7% | +59.5% |
| Volatility (ann.) | 30.1% | 44.7% |
| Beta vs S&P 500 | 0.53 | 0.72 |
| Max drawdown (3Y) | -57.7% | -52.4% |
| Market cap | $32.7B | $10.4B |
| P/E (trailing) | 39.2 | – |
| Dividend yield | 0.00% | 0.00% |
| Sector / category | Health Care | US Listed |
Year-by-year returns
| Year | BIIB | IONS |
|---|---|---|
| 2022 | +15.4% | +24.1% |
| 2023 | -6.6% | +33.9% |
| 2024 | -40.9% | -30.9% |
| 2025 | +15.1% | +126.3% |
| 2026 | +25.9% | -21.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BIIB and IONS good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.47 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between BIIB and IONS?
Using weekly returns as of 2026-08-27: 0.47 over 3 years, with 0.44 over the last year and 0.43 over 5 years.
Is IONS a good diversifier for BIIB?
Yes, to a useful degree: a correlation of 0.47 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.47 mean?
On the −1 to +1 scale, 0.47 describes how much the two returns move together: +1 is lockstep, 0 is independence, negative values mean opposite directions. It says nothing about which performed better.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/biib-vs-ions.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/biib-vs-ions/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: BIIB correlations · IONS correlations
