Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.
IBB vs SPY: how they differ
IBB and SPY hold 1% of their weight in the same names, and IBB returned more over the year.
iShares Biotechnology ETF and SPDR S&P 500 ETF Trust.
What they hold in common
By the books each fund has filed, IBB and SPY hold 1% of their money in the same securities at the same weight.
| Holding | IBB | SPY |
|---|---|---|
| Amgen, Inc. | 7.84% | 0.30% |
| Gilead Sciences, Inc. | 6.85% | 0.24% |
| Vertex Pharmaceuticals, Inc. | 8.09% | 0.20% |
| Regeneron Pharmaceuticals, Inc. | 4.91% | 0.10% |
| Biogen, Inc. | 2.47% | 0.05% |
| Moderna, Inc. | 1.99% | 0.04% |
| Incyte Corp. | 1.75% | 0.03% |
| Bio-Techne Corp. | 0.86% | 0.02% |
| Charles River Laboratories International | 0.84% | 0.02% |
| Only in IBB | Only in SPY |
|---|---|
| Argenx SE 3.76% | NVIDIA Corp. 7.52% |
| Alnylam Pharmaceuticals, Inc. 3.12% | Apple, Inc. 6.59% |
| Natera, Inc. 2.89% | Microsoft Corp. 4.30% |
| Revolution Medicines, Inc. 2.78% | Amazon.com, Inc. 3.62% |
| Illumina, Inc. 2.07% | Alphabet, Inc. 3.25% |
| Insmed, Inc. 1.79% | Broadcom, Inc. 2.77% |
| BeOne Medicines Ltd. 1.77% | Alphabet, Inc. 2.59% |
| United Therapeutics Corp. 1.74% | Micron Technology, Inc. 2.02% |
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 | SPY SPDR S&P 500 ETF Trust | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | iShares | State Street |
| What it is | Biotechnology | S&P 500, book from IVV |
| Total return, 1 year | +41.5% | +17.5% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | +24.0 pts | 0.0 pts |
| Expense ratio | 0.44% | 0.09% |
| Already in the S&P 500 | 35.6% | 100.0% |
| Holdings | 248 | 504 |
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.
SPY in plain words
SPY is an index equity fund tracking the S&P 500. Over the year to Sep 11, 2026 it returned +17.5% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.09% a year. By its holdings filed for Jun 30, 2026, 100% of the fund by weight is stocks the S&P 500 also holds, across 504 positions, with the top ten at 36.4%.
Questions people ask
- Which returned more over the last year, IBB or SPY?
- In the year to Sep 12, 2026, with distributions reinvested, IBB returned +41.5% and SPY returned +17.5%, so IBB returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, IBB or SPY?
- IBB charges 0.44% a year and SPY charges 0.09%, so SPY is cheaper. Fees come from each fund's prospectus.
- How much do IBB and SPY overlap with the S&P 500?
- By their latest filed holdings, 36% of IBB and 100% of SPY by weight is stocks the S&P 500 already holds. Between the two funds, 1% 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 SPY, data as of Sep 12, 2026. https://etfiq.com/compare/any/IBB-SPY Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources