Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.
IBB vs IWO: how they differ
IBB and IWO hold 15% of their weight in the same names, and IBB returned more over the year.
iShares Biotechnology ETF and iShares Russell 2000 Growth ETF.
What they hold in common
By the books each fund has filed, IBB and IWO hold 15% of their money in the same securities at the same weight.
| Holding | IBB | IWO |
|---|---|---|
| Krystal Biotech, Inc. | 0.75% | 0.58% |
| Praxis Precision Medicines, Inc. | 0.68% | 0.51% |
| Protagonist Therapeutics, Inc. | 0.58% | 0.45% |
| Alkermes plc | 0.67% | 0.42% |
| Nuvalent, Inc. | 0.50% | 0.40% |
| Spyre Therapeutics, Inc. | 0.54% | 0.40% |
| Cogent Biosciences, Inc. | 0.45% | 0.39% |
| Twist Bioscience Corp. | 0.48% | 0.38% |
| Rhythm Pharmaceuticals, Inc. | 0.57% | 0.37% |
| Definium Therapeutics, Inc. | 0.39% | 0.36% |
| Apogee Therapeutics, Inc. | 0.59% | 0.36% |
| Kymera Therapeutics, Inc. | 0.64% | 0.36% |
| Only in IBB | Only in IWO |
|---|---|
| Vertex Pharmaceuticals, Inc. 8.09% | Moog, Inc. 0.73% |
| Amgen, Inc. 7.84% | BrightSpring Health Services, Inc. 0.68% |
| Gilead Sciences, Inc. 6.85% | MaxLinear, Inc. 0.67% |
| Regeneron Pharmaceuticals, Inc. 4.91% | Argan, Inc. 0.66% |
| Argenx SE 3.76% | JFrog Ltd. 0.60% |
| Alnylam Pharmaceuticals, Inc. 3.12% | ESCO Technologies, Inc. 0.56% |
| Natera, Inc. 2.89% | FirstCash Holdings, Inc. 0.54% |
| Revolution Medicines, Inc. 2.78% | D-Wave Quantum, Inc. 0.53% |
Weight overlap is an ETFIQ calculation: for every security both funds hold, the smaller of the two weights, summed. Above 50%, holding both is close to holding one of them twice. Holdings dated Jun 30, 2026.
| IBB iShares Biotechnology ETF | IWO iShares Russell 2000 Growth ETF | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | iShares | iShares |
| What it is | Biotechnology | Russell 2000 Growth |
| Total return, 1 year | +41.5% | +17.0% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | +24.0 pts | −0.5 pts |
| Expense ratio | 0.44% | 0.24% |
| Already in the S&P 500 | 35.6% | 0.0% |
| Holdings | 248 | 1133 |
IBB in plain words
IBB is an index equity fund tracking the Biotechnology. Over the year to Sep 11, 2026 it returned +41.5% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.44% a year. By its holdings filed for Jun 30, 2026, 36% of the fund by weight is stocks the S&P 500 also holds, across 248 positions, with the top ten at 44.8%. It sat 6.5% below its high of Aug 19, 2026 on Sep 11, 2026.
IWO in plain words
IWO is an index equity fund tracking the Russell 2000 Growth. Over the year to Sep 11, 2026 it returned +17.0% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.24% a year. By its holdings filed for Jun 30, 2026, 0% of the fund by weight is stocks the S&P 500 also holds, across 1133 positions, with the top ten at 6.1%. It sat 7.1% below its high of Aug 14, 2026 on Sep 11, 2026.
Questions people ask
- Which returned more over the last year, IBB or IWO?
- In the year to Sep 12, 2026, with distributions reinvested, IBB returned +41.5% and IWO returned +17.0%, so IBB returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, IBB or IWO?
- IBB charges 0.44% a year and IWO charges 0.24%, so IWO is cheaper. Fees come from each fund's prospectus.
- How much do IBB and IWO overlap with the S&P 500?
- By their latest filed holdings, 36% of IBB and 0% of IWO by weight is stocks the S&P 500 already holds. Between the two funds, 15% of their books are the same securities at the same weight.
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Where these figures came from
ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.
Cite this page. ETFIQ, IBB against IWO, data as of Sep 12, 2026. https://etfiq.com/compare/any/IBB-IWO Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources