Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.
VO vs VOO: how they differ
VO and VOO hold 16% of their weight in the same names, and VOO returned more over the year.
Vanguard Mid-Cap Index Fund and Vanguard 500 Index Fund.
What they hold in common
By the books each fund has filed, VO and VOO hold 16% of their money in the same securities at the same weight.
| Holding | VO | VOO |
|---|---|---|
| Western Digital Corp | 1.07% | 0.34% |
| Seagate Technology Holdings PLC | 1.05% | 0.34% |
| Vertiv Holdings Co | 1.23% | 0.20% |
| Quanta Services Inc | 1.05% | 0.17% |
| Howmet Aerospace Inc | 1.04% | 0.17% |
| Newmont Corp | 0.48% | 0.15% |
| Cummins Inc | 0.95% | 0.15% |
| Fortinet Inc | 0.46% | 0.15% |
| Williams Cos Inc/The | 0.44% | 0.14% |
| Johnson Controls International plc | 0.43% | 0.14% |
| Datadog Inc | 0.84% | 0.13% |
| Constellation Energy Corp | 0.78% | 0.12% |
| Only in VO | Only in VOO |
|---|---|
| Bloom Energy Corp 0.79% | NVIDIA Corp 7.53% |
| Cloudflare Inc 0.76% | Apple Inc 6.61% |
| Rocket Lab Corp 0.57% | Microsoft Corp 4.31% |
| Cheniere Energy Inc 0.49% | Amazon.com Inc 3.63% |
| Ferguson Enterprises Inc 0.45% | Alphabet Inc 3.26% |
| Waste Connections Inc 0.41% | Broadcom Inc 2.78% |
| Snowflake Inc 0.41% | Alphabet Inc 2.60% |
| Alnylam Pharmaceuticals Inc 0.39% | 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.
| VO Vanguard Mid-Cap Index Fund | VOO Vanguard 500 Index Fund | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | Vanguard | Vanguard |
| What it is | Mid-Cap | S&P 500 |
| Total return, 1 year | +12.0% | +17.6% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | −5.5 pts | +0.1 pts |
| Expense ratio | 0.03% | 0.03% |
| Already in the S&P 500 | 91.4% | 100.0% |
| Holdings | 282 | 506 |
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.
VOO in plain words
VOO is an index equity fund tracking the S&P 500. Over the year to Sep 11, 2026 it returned +17.6% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. By its holdings filed for Jun 30, 2026, 100% of the fund by weight is stocks the S&P 500 also holds, across 506 positions, with the top ten at 36.5%.
Questions people ask
- Which returned more over the last year, VO or VOO?
- In the year to Sep 12, 2026, with distributions reinvested, VO returned +12.0% and VOO returned +17.6%, so VOO returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, VO or VOO?
- VO charges 0.03% a year and VOO charges 0.03%, so VO is cheaper. Fees come from each fund's prospectus.
- How much do VO and VOO overlap with the S&P 500?
- By their latest filed holdings, 91% of VO and 100% of VOO by weight is stocks the S&P 500 already holds. Between the two funds, 16% 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, VO against VOO, data as of Sep 12, 2026. https://etfiq.com/compare/any/VO-VOO Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources