IBB vs IONS: Correlation
Measured on weekly returns over the past three years, iShares Biotechnology ETF (IBB) 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 IBB and IONS?
On 3 years of weekly data the IBB/IONS correlation comes out at 0.47, moderate. The relationship has been stable: the 1-year correlation (0.47) sits close to the 3-year figure. The 5-year figure is 0.48, and annualized covariance runs at 437.0 %².
By 3-year correlation, IONS places #113 of the 168 assets tracked against IBB. Over the last 12 months IBB came out ahead by 9.4 percentage points (+55.4% against +46.0%). Note the risk asymmetry: IONS runs 2.2 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
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 IONS: side by side
| IBB (iShares Biotechnology ETF) | IONS (Ionis Pharmaceuticals, Inc.) | |
|---|---|---|
| 1-year return | +55.4% | +46.0% |
| 5-year return | +26.6% | +59.5% |
| Volatility (ann.) | 20.7% | 44.7% |
| Beta vs S&P 500 | 0.81 | 0.72 |
| Max drawdown (3Y) | -24.9% | -52.4% |
| Market cap | – | $10.4B |
| P/E (trailing) | – | – |
| Dividend yield | 0.22% | 0.00% |
| Expense ratio | 0.44% | – |
| Assets under management | $9.2B | – |
| Sector / category | ETF · Thematic | US Listed |
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 | IONS |
|---|---|---|
| 2022 | -13.7% | +24.1% |
| 2023 | +3.8% | +33.9% |
| 2024 | -2.4% | -30.9% |
| 2025 | +28.0% | +126.3% |
| 2026 | +27.4% | -21.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
IONS represents 0.71% of IBB's portfolio, so part of any move in IBB is IONS itself, and the correlation between them is partly mechanical.
Are IBB and IONS good diversifiers for each other?
Reasonably. At 0.47, IBB and IONS keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between IBB and IONS?
As of 2026-08-27, the correlation of weekly returns between IBB and IONS is 0.47 over 3 years, 0.47 over 1 year and 0.48 over 5 years.
Is IONS a good diversifier for IBB?
Reasonably. At 0.47, IBB and IONS keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.47 mean?
A reading of 0.47 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/ibb-vs-ions.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/ibb-vs-ions/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: IBB correlations · IONS correlations
