Data as of Sep 13, 2026. Both funds on the fields they both publish, from the same sources.
IBB vs IWC: how they differ
IBB and IWC hold 4% of their weight in the same names, and IBB returned more over the year.
iShares Biotechnology ETF and iShares Micro-Cap ETF.
What they hold in common
By the books each fund has filed, IBB and IWC hold 4% of their money in the same securities at the same weight.
| Holding | IBB | IWC |
|---|---|---|
| NURIX THERAPEUTICS | 0.19% | 0.59% |
| CAREDX | 0.17% | 0.61% |
| MBX BIOSCIENCES | 0.13% | 0.45% |
| NUVATION BIO CLASS A | 0.12% | 0.37% |
| UROGEN PHARMA | 0.12% | 0.43% |
| ABSCI CORP | 0.09% | 0.27% |
| RAPPORT THERAPEUTICS | 0.09% | 0.31% |
| REPLIMUNE GROUP | 0.09% | 0.25% |
| ALTO NEUROSCIENCE INC | 0.08% | 0.20% |
| PRECIGEN | 0.08% | 0.30% |
| ARRIVENT BIOPHARMA | 0.07% | 0.26% |
| CASTLE BIOSCIENCES | 0.07% | 0.23% |
| Only in IBB | Only in IWC |
|---|---|
| VERTEX PHARMACEUTICALS 7.94% | SELLAS LIFE SCIENCES GROUP INC 0.60% |
| AMGEN INC 7.85% | PENGUIN SOLUTIONS INC 0.58% |
| GILEAD SCIENCES 7.44% | OUSTER 0.52% |
| REGENERON PHARMACEUTICALS 5.92% | VIRIDIAN THERAPEUTICS ORS 0.48% |
| ARGENX SE ADR 3.78% | INTERFACE 0.47% |
| MODERNA 3.67% | INNODATA 0.40% |
| NATERA 3.30% | QCR HOLDINGS INC 0.40% |
| REVOLUTION MEDICINES 2.87% | STRIVE INC CLASS A 0.40% |
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 Sep 10, 2026.
| IBB iShares Biotechnology ETF | IWC iShares Micro-Cap ETF | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | iShares | iShares |
| What it is | Biotechnology | Russell Microcap |
| Total return, 1 year | +41.5% | +31.3% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | +24.0 pts | +13.8 pts |
| Expense ratio | 0.44% | not published |
| Already in the S&P 500 | 35.6% | 91.9% |
| Holdings | 233 | 1252 |
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 Sep 10, 2026, 36% of the fund by weight is stocks the S&P 500 also holds, across 233 positions, with the top ten at 47.5%. It sat 6.5% below its high of Aug 19, 2026 on Sep 11, 2026.
IWC in plain words
IWC is an index equity fund tracking the Russell Microcap. Over the year to Sep 11, 2026 it returned +31.3% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. By its holdings filed for Sep 10, 2026, 92% of the fund by weight is stocks the S&P 500 also holds, across 1252 positions, with the top ten at 5.1%. It sat 5.0% below its high of Aug 14, 2026 on Sep 11, 2026.
Questions people ask
- Which returned more over the last year, IBB or IWC?
- In the year to Sep 13, 2026, with distributions reinvested, IBB returned +41.5% and IWC returned +31.3%, so IBB returned more. One year is one year; the longer windows are in the table.
- How much do IBB and IWC overlap with the S&P 500?
- By their latest filed holdings, 36% of IBB and 92% of IWC by weight is stocks the S&P 500 already holds. Between the two funds, 4% of their books are the same securities at the same weight.
Other comparisons
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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 IWC, data as of Sep 13, 2026. https://etfiq.com/compare/any/ibb-vs-iwc Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources