Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.
IBB vs XBI: how they differ
IBB and XBI hold 40% of their weight in the same names, and XBI returned more over the year.
iShares Biotechnology ETF and State Street(R) SPDR(R) S&P(R) Biotech ETF.
What they hold in common
By the books each fund has filed, IBB and XBI hold 40% of their money in the same securities at the same weight.
| Holding | IBB | XBI |
|---|---|---|
| Moderna, Inc. | 1.99% | 1.41% |
| Revolution Medicines, Inc. | 2.78% | 1.21% |
| Natera, Inc. | 2.89% | 1.17% |
| Insmed, Inc. | 1.79% | 1.08% |
| Vertex Pharmaceuticals, Inc. | 8.09% | 1.06% |
| Biogen, Inc. | 2.47% | 1.03% |
| Ionis Pharmaceuticals, Inc. | 1.00% | 1.00% |
| Incyte Corp. | 1.75% | 1.00% |
| Amgen, Inc. | 7.84% | 1.00% |
| Bridgebio Pharma, Inc. | 0.98% | 1.03% |
| Neurocrine Biosciences, Inc. | 1.30% | 0.97% |
| Gilead Sciences, Inc. | 6.85% | 0.97% |
| Only in IBB | Only in XBI |
|---|---|
| Argenx SE 3.76% | Viking Therapeutics Inc 1.31% |
| Illumina, Inc. 2.07% | SELLAS Life Sciences Group Inc 1.19% |
| BeOne Medicines Ltd. 1.77% | Dianthus Therapeutics Inc 1.19% |
| Roivant Sciences Ltd. 1.43% | Roivant Sciences Ltd 1.16% |
| Ascendis Pharma A/S 1.29% | Alkermes PLC 1.11% |
| Genmab A/S 1.12% | Celcuity Inc 1.10% |
| Medpace Holdings, Inc. 0.95% | TG Therapeutics Inc 1.09% |
| Bio-Techne Corp. 0.86% | AbbVie Inc 1.04% |
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 | XBI State Street(R) SPDR(R) S&P(R) Biotech ETF | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | iShares | State Street |
| What it is | Biotechnology | SPDR S&P Biotech |
| Total return, 1 year | +41.5% | +64.0% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | +24.0 pts | +46.5 pts |
| Expense ratio | 0.44% | 0.35% |
| Already in the S&P 500 | 35.6% | 8.5% |
| Holdings | 248 | 150 |
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.
XBI in plain words
XBI is an index equity fund tracking the SPDR S&P Biotech. Over the year to Sep 11, 2026 it returned +64.0% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.35% a year. By its holdings filed for Jun 30, 2026, 8% of the fund by weight is stocks the S&P 500 also holds, across 150 positions, with the top ten at 13.3%. It sat 9.6% below its high of Feb 8, 2021 on Sep 11, 2026.
Questions people ask
- Which returned more over the last year, IBB or XBI?
- In the year to Sep 12, 2026, with distributions reinvested, IBB returned +41.5% and XBI returned +64.0%, so XBI returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, IBB or XBI?
- IBB charges 0.44% a year and XBI charges 0.35%, so XBI is cheaper. Fees come from each fund's prospectus.
- How much do IBB and XBI overlap with the S&P 500?
- By their latest filed holdings, 36% of IBB and 8% of XBI by weight is stocks the S&P 500 already holds. Between the two funds, 40% 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 XBI, data as of Sep 12, 2026. https://etfiq.com/compare/any/IBB-XBI Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources