IBB vs RYTM: Correlation
How closely do iShares Biotechnology ETF (IBB) and Rhythm Pharmaceuticals, Inc. (RYTM) trade together? Their weekly returns over three years give a correlation of 0.53, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are IBB and RYTM?
Across a 3-year window, the weekly returns of IBB and RYTM correlate at 0.53, moderate. Recent behaviour matches the longer record: 0.51 over 1 year against 0.53 over 3. Stretching to 5 years gives 0.31, with an annualized covariance of 637.5 %².
Among the 168 assets we track against IBB, RYTM ranks #77 by 3-year correlation. The last year tells two different stories: IBB led by 45.4 percentage points, +55.4% for IBB against +10.0% for RYTM. Risk is not evenly split, since RYTM carries 2.8 times the volatility of the other side.
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 RYTM: side by side
| IBB (iShares Biotechnology ETF) | RYTM (Rhythm Pharmaceuticals, Inc.) | |
|---|---|---|
| 1-year return | +55.4% | +10.0% |
| 5-year return | +26.6% | +785.4% |
| Volatility (ann.) | 20.7% | 58.4% |
| Beta vs S&P 500 | 0.81 | 1.92 |
| Max drawdown (3Y) | -24.9% | -35.5% |
| Market cap | – | $7.7B |
| P/E (trailing) | – | – |
| Dividend yield | 0.22% | 0.00% |
| Expense ratio | 0.44% | – |
| Assets under management | $9.2B | – |
| Sector / category | ETF · Thematic | US Listed |
On the fund side, IBB sits in the Health category at iShares, with $9.2B under management, 235 holdings, a 0.44% expense ratio, a 0.22% trailing dividend yield.
Year-by-year returns
| Year | IBB | RYTM |
|---|---|---|
| 2022 | -13.7% | +191.8% |
| 2023 | +3.8% | +57.9% |
| 2024 | -2.4% | +21.8% |
| 2025 | +28.0% | +91.2% |
| 2026 | +27.4% | +5.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 0.51% of IBB is RYTM itself, so the fund partly moves with the stock by construction.
Are IBB and RYTM good diversifiers for each other?
To a limited degree. At 0.53 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 IBB and RYTM?
As of 2026-08-27, the correlation of weekly returns between IBB and RYTM is 0.53 over 3 years, 0.51 over 1 year and 0.31 over 5 years.
Is RYTM a good diversifier for IBB?
To a limited degree. At 0.53 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 0.53 mean?
On the −1 to +1 scale, 0.53 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/ibb-vs-rytm.json
Markdown for the live badge, attribution link included:
[](https://www.pairbook.io/pair/ibb-vs-rytm/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: IBB correlations · RYTM correlations
