Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.
VO vs XBI: how they differ
VO and XBI hold 1% of their weight in the same names, and XBI returned more over the year.
Vanguard Mid-Cap Index Fund and State Street(R) SPDR(R) S&P(R) Biotech ETF.
What they hold in common
By the books each fund has filed, VO and XBI hold 1% of their money in the same securities at the same weight.
| Holding | VO | XBI |
|---|---|---|
| Alnylam Pharmaceuticals Inc | 0.39% | 0.96% |
| Regeneron Pharmaceuticals Inc | 0.31% | 0.96% |
| Biogen Inc | 0.31% | 1.03% |
| Insmed Inc | 0.11% | 1.08% |
| Only in VO | Only in XBI |
|---|---|
| Vertiv Holdings Co 1.23% | Apogee Therapeutics Inc 1.49% |
| Western Digital Corp 1.07% | Moderna Inc 1.41% |
| Seagate Technology Holdings PLC 1.05% | Twist Bioscience Corp 1.41% |
| Quanta Services Inc 1.05% | Oruka Therapeutics Inc 1.38% |
| Howmet Aerospace Inc 1.04% | Kymera Therapeutics Inc 1.36% |
| Cummins Inc 0.95% | Viking Therapeutics Inc 1.31% |
| Datadog Inc 0.84% | Praxis Precision Medicines Inc 1.29% |
| Bloom Energy Corp 0.79% | Erasca Inc 1.27% |
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.
| VO Vanguard Mid-Cap Index Fund | XBI State Street(R) SPDR(R) S&P(R) Biotech ETF | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | Vanguard | State Street |
| What it is | Mid-Cap | SPDR S&P Biotech |
| Total return, 1 year | +12.0% | +64.0% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | −5.5 pts | +46.5 pts |
| Expense ratio | 0.03% | 0.35% |
| Already in the S&P 500 | 91.4% | 8.5% |
| Holdings | 282 | 150 |
VO in plain words
VO is an index equity fund tracking the Mid-Cap. Over the year to Sep 11, 2026 it returned +12.0% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.03% a year. By its holdings filed for Jun 30, 2026, 91% of the fund by weight is stocks the S&P 500 also holds, across 282 positions, with the top ten at 9.6%. It sat 4.1% below its high of Aug 14, 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, VO or XBI?
- In the year to Sep 12, 2026, with distributions reinvested, VO returned +12.0% and XBI returned +64.0%, so XBI returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, VO or XBI?
- VO charges 0.03% a year and XBI charges 0.35%, so VO is cheaper. Fees come from each fund's prospectus.
- How much do VO and XBI overlap with the S&P 500?
- By their latest filed holdings, 91% of VO and 8% of XBI 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.
Other comparisons
Where to next
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, VO against XBI, data as of Sep 12, 2026. https://etfiq.com/compare/any/VO-XBI Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources