IBB vs VRTX: Correlation
How closely do iShares Biotechnology ETF (IBB) and Vertex Pharmaceuticals (VRTX) trade together? Their weekly returns over three years give a correlation of 0.61, which is strong.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are IBB and VRTX?
Across a 3-year window, the weekly returns of IBB and VRTX correlate at 0.61, strong. The relationship has been stable: the 1-year correlation (0.68) sits close to the 3-year figure. Stretching to 5 years gives 0.56, with an annualized covariance of 385.1 %².
Within IBB's tracked universe of 168 assets, VRTX comes in at #28 by 3-year correlation. Over the last 12 months IBB came out ahead by 14.7 percentage points (+55.4% against +40.7%). The rolling one-year correlation stayed in a tight band between 0.49 and 0.68 over the past three years, which points to a structural rather than episodic relationship.
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.
IBB vs VRTX: side by side
| IBB (iShares Biotechnology ETF) | VRTX (Vertex Pharmaceuticals) | |
|---|---|---|
| 1-year return | +55.4% | +40.7% |
| 5-year return | +26.6% | +174.5% |
| Volatility (ann.) | 20.7% | 30.3% |
| Beta vs S&P 500 | 0.81 | 0.55 |
| Max drawdown (3Y) | -24.9% | -29.1% |
| Market cap | – | $138.8B |
| P/E (trailing) | – | 31.9 |
| Dividend yield | 0.22% | 0.00% |
| Expense ratio | 0.44% | – |
| Assets under management | $9.2B | – |
| Sector / category | ETF · Thematic | Health Care |
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 | IBB | VRTX |
|---|---|---|
| 2022 | -13.7% | +31.5% |
| 2023 | +3.8% | +40.9% |
| 2024 | -2.4% | -1.0% |
| 2025 | +28.0% | +12.6% |
| 2026 | +27.4% | +20.8% |
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 VRTX at a 7.89% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are IBB and VRTX good diversifiers for each other?
Only partially. A correlation of 0.61 means IBB and VRTX 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 IBB and VRTX?
The IBB/VRTX correlation stands at 0.61 on a 3-year window (1 year: 0.68, 5 years: 0.56), computed from weekly returns as of 2026-08-27.
Is VRTX a good diversifier for IBB?
Only partially. A correlation of 0.61 means IBB and VRTX share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
What does a correlation of 0.61 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/ibb-vs-vrtx.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/ibb-vs-vrtx/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: IBB correlations · VRTX correlations
