VO vs XBI ETF holdings comparison
Vanguard Mid-Cap ETF (VO) · SPDR S&P Biotech ETF (XBI)
VO and XBI overlap by 1% by portfolio weight. The remaining 99.0 percentage points are not counted as shared holdings weight by this calculation. They share 3 stocks; the largest shared position is Alnylam Pharmaceuticals Inc (ALNY), contributing 0.48% to the overlap.
The holdings dates differ. This can slightly understate overlap for funds tracking similar indexes.
What this means
VO and XBI share a smaller portion of their portfolio weight in the same underlying stocks. OverlapCheck labels this "low holdings overlap" using house ranges of 70% or more, 30% to under 70%, and under 30%. These descriptive ranges are not industry standards or investment guidance. Holdings overlap does not measure correlation, volatility, geographic or factor exposure, fees, or suitability.
Overlap by weight sums the smaller of the two funds' weights for every stock they both hold. It answers "how much of my money is in the same stocks either way?" See methodology.
This comparison covers normalized equity positions represented in the dataset. Cash, derivatives, options, structured notes, and other non-equity assets are not included, so the result is not a complete comparison of every asset or risk in either fund.
Top shared holdings
| Company | Ticker | in VO | in XBI |
|---|---|---|---|
| Alnylam Pharmaceuticals Inc | ALNY | 0.48% | 0.73% |
| Biogen Inc | BIIB | 0.29% | 1.00% |
| Insmed Inc | INSM | 0.19% | 1.19% |
Holdings only in VO or XBI
VO has 285 fund-only positions representing approximately 98.7 percentage points of reported exposure; XBI has 144 fund-only positions representing approximately 97.0 percentage points of reported exposure. These are positions whose normalized security identifiers appear in one issuer file but not the other.
Largest positions only in VO
| Company | Ticker | Weight |
|---|---|---|
| Vertiv Holdings Co | VRT | 1.03% |
| Howmet Aerospace Inc | HWM | 1.01% |
| Western Digital Corp | WDC | 1.00% |
| Constellation Energy Corp | CEG | 0.94% |
| Seagate Technology Holdings PLC | STX | 0.93% |
| Quanta Services Inc | PWR | 0.89% |
| SLB Ltd | SLB | 0.84% |
| Cummins Inc | CMI | 0.81% |
| Valero Energy Corp | VLO | 0.80% |
| Phillips 66 | PSX | 0.80% |
Largest positions only in XBI
| Company | Ticker | Weight |
|---|---|---|
| Moderna Inc | MRNA | 3.05% |
| Twist Bioscience Corp | TWST | 1.98% |
| Apogee Therapeutics Inc | APGE | 1.44% |
| Kymera Therapeutics Inc | KYMR | 1.43% |
| Oruka Therapeutics Inc | ORKA | 1.41% |
| Natera Inc | NTRA | 1.38% |
| Halozyme Therapeutics Inc | HALO | 1.37% |
| Praxis Precision Medicines I | PRAX | 1.35% |
| Dianthus Therapeutics Inc | DNTH | 1.30% |
| Revolution Medicines Inc | RVMD | 1.30% |
FAQ
How much do VO and XBI overlap?
VO and XBI have 1% overlap by weight, sharing 3 equity positions (out of 288 in VO and 147 in XBI). The official holdings files used are dated 2026-03-31 for VO and 2026-08-25 for XBI.
What does 1% overlap mean?
VO and XBI share a smaller portion of their portfolio weight in the same underlying stocks. OverlapCheck labels this "low holdings overlap" using house ranges of 70% or more, 30% to under 70%, and under 30%. These descriptive ranges are not industry standards or investment guidance. Holdings overlap does not measure correlation, volatility, geographic or factor exposure, fees, or suitability.
Which stocks do VO and XBI both hold?
The largest shared positions are Alnylam Pharmaceuticals Inc, Biogen Inc, Insmed Inc. The top shared holdings with weights in each fund are shown on this page.
What holdings are different between VO and XBI?
VO has 285 positions not found in XBI, while XBI has 144 positions not found in VO. The largest fund-only positions and their weights are shown on this page.