BIIB vs IBB: Correlation
Measured on weekly returns over the past three years, Biogen (BIIB) and iShares Biotechnology ETF (IBB) carry a correlation of 0.58, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BIIB and IBB?
Over the past 3 years, BIIB and IBB moved with a correlation of 0.58, which is moderate. Little has changed lately, as the 1-year reading of 0.50 lands near the 3-year figure. Over 5 years the correlation is 0.52, and the annualized covariance of weekly returns is 363.3 %².
Few assets follow BIIB as closely as IBB, which ranks #1 of 32 tracked partners. Over the last 12 months BIIB came out ahead by 7.0 percentage points (+62.4% against +55.4%). Across three years, the rolling one-year figure varied moderately, from 0.38 to 0.75.
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 IBB: side by side
| BIIB (Biogen) | IBB (iShares Biotechnology ETF) | |
|---|---|---|
| 1-year return | +62.4% | +55.4% |
| 5-year return | -35.7% | +26.6% |
| Volatility (ann.) | 30.1% | 20.7% |
| Beta vs S&P 500 | 0.53 | 0.81 |
| Max drawdown (3Y) | -57.7% | -24.9% |
| Market cap | $32.7B | – |
| P/E (trailing) | 39.2 | – |
| Dividend yield | 0.00% | 0.22% |
| Expense ratio | – | 0.44% |
| Assets under management | – | $9.2B |
| Sector / category | Health Care | ETF · Thematic |
IBB, iShares's Health fund, carries $9.2B under management, 235 holdings, a 0.44% expense ratio, a 0.22% trailing dividend yield.
Year-by-year returns
| Year | BIIB | IBB |
|---|---|---|
| 2022 | +15.4% | -13.7% |
| 2023 | -6.6% | +3.8% |
| 2024 | -40.9% | -2.4% |
| 2025 | +15.1% | +28.0% |
| 2026 | +25.9% | +27.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
Keep in mind that IBB holds BIIB at a 2.23% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are BIIB and IBB good diversifiers for each other?
Only partially. A correlation of 0.58 means BIIB and IBB share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
FAQ
What is the correlation between BIIB and IBB?
As of 2026-08-27, the correlation of weekly returns between BIIB and IBB is 0.58 over 3 years, 0.50 over 1 year and 0.52 over 5 years.
Is IBB a good diversifier for BIIB?
Only partially. A correlation of 0.58 means BIIB and IBB share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
What does a correlation of 0.58 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-ibb.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/biib-vs-ibb/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: BIIB correlations · IBB correlations
