FDMT vs IBB: Correlation
How closely do 4D Molecular Therapeutics, Inc. (FDMT) and iShares Biotechnology ETF (IBB) trade together? Their weekly returns over three years give a correlation of 0.44, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are FDMT and IBB?
Across a 3-year window, the weekly returns of FDMT and IBB correlate at 0.44, moderate. Little has changed lately, as the 1-year reading of 0.53 lands near the 3-year figure. Stretching to 5 years gives 0.42, with an annualized covariance of 823.0 %².
Within FDMT's tracked universe of 15 assets, IBB comes in at #5 by 3-year correlation. Their recent paths diverged sharply: over the last 12 months FDMT outperformed by 75.4 percentage points (+130.8% for FDMT against +55.4% for IBB). Risk is not evenly split, since FDMT carries 4.3 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.
FDMT vs IBB: side by side
| FDMT (4D Molecular Therapeutics, Inc.) | IBB (iShares Biotechnology ETF) | |
|---|---|---|
| 1-year return | +130.8% | +55.4% |
| 5-year return | -50.9% | +26.6% |
| Volatility (ann.) | 89.9% | 20.7% |
| Beta vs S&P 500 | 1.09 | 0.81 |
| Max drawdown (3Y) | -93.0% | -24.9% |
| Market cap | $0.8B | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 0.22% |
| Expense ratio | – | 0.44% |
| Assets under management | – | $9.2B |
| Sector / category | US Listed | 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 | FDMT | IBB |
|---|---|---|
| 2022 | +1.2% | -13.7% |
| 2023 | -8.8% | +3.8% |
| 2024 | -72.5% | -2.4% |
| 2025 | +34.6% | +28.0% |
| 2026 | +98.8% | +27.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
FDMT represents 0.05% of IBB's portfolio, so part of any move in IBB is FDMT itself, and the correlation between them is partly mechanical.
Are FDMT and IBB good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.44 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between FDMT and IBB?
As of 2026-08-27, the correlation of weekly returns between FDMT and IBB is 0.44 over 3 years, 0.53 over 1 year and 0.42 over 5 years.
Is IBB a good diversifier for FDMT?
Yes, to a useful degree: a correlation of 0.44 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.44 mean?
A reading of 0.44 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/fdmt-vs-ibb.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/fdmt-vs-ibb/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: FDMT correlations · IBB correlations
