VO vs VOO: how much do they really overlap?
VO (Vanguard Mid-Cap ETF, tracking the CRSP US Mid Cap) and VOO (Vanguard S&P 500 ETF, tracking the S&P 500) overlap by roughly 0% by weight. 0 of VO's top 10 holdings also appear in VOO. A 50/50 blend of the two behaves like about 187 equally-weighted bets (diversification grade A). In short, the two funds hold almost none of the same securities — they are complementary, not redundant.
The same companies, in both funds
These 0 holdings appear in both VO and VOO. The weight columns show how much of each fund each name represents.
| Holding | in VO | in VOO |
|---|
Only in VO
Vanguard Mid-Cap ETF — US mid-cap. Its biggest holdings that VOO doesn’t have:
| VRT Vertiv Holdings Co. Class A | 1.22% |
| WDC Western Digital Corp. | 1.06% |
| STX Seagate Technology Holdings plc | 1.04% |
| PWR Quanta Services Inc. | 1.04% |
| HWM Howmet Aerospace Inc. | 1.04% |
| CMI Cummins Inc. | 0.95% |
| DDOG Datadog Inc. Class A | 0.83% |
| BE Bloom Energy Corp. Class A | 0.79% |
Only in VOO
Vanguard S&P 500 ETF — US large-cap. Its biggest holdings that VO doesn’t have:
| NVDA NVIDIA Corp. | 7.51% |
| AAPL Apple Inc. | 6.59% |
| MSFT Microsoft Corp. | 4.30% |
| AMZN Amazon.com Inc. | 3.62% |
| GOOGL Alphabet Inc. Class A | 3.25% |
| AVGO Broadcom Inc. | 2.77% |
| GOOG Alphabet Inc. Class C | 2.59% |
| MU Micron Technology Inc. | 2.02% |
So — essentially different. Should you hold both?
VO and VOO hold almost none of the same securities — they are complementary, not redundant. Held together they genuinely broaden your exposure — a 50/50 blend reaches ~187 effective positions (grade A), because they hold largely different securities.
Holdings as of — VO: Jun 30, 2026 (Vanguard); VOO: Jun 30, 2026 (Vanguard). Refreshed monthly. Overlap is measured across each fund’s largest holdings (top 50); the diffuse long tail barely moves the math.
See this for YOUR whole portfolio, free →VO vs VOO — FAQ
- How much do VO and VOO overlap?
- VO and VOO overlap by approximately 0% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 0 of VO's 10 largest holdings are also held by VOO. They share 0 of their listed top holdings in total.
- Is it redundant to hold both VO and VOO?
- Because they hold almost none of the same securities — they are complementary, not redundant, holding both is not redundant — each fund covers largely different holdings, so together they broaden your exposure. A 50/50 blend has an effective 187 positions and a A diversification grade.
- What does VOO hold that VO doesn't?
- VOO's largest holdings that VO doesn't hold include NVDA, AAPL, MSFT, AMZN, GOOGL. Its category is US large-cap, versus VO's US mid-cap.
- Which is more concentrated, VO or VOO?
- VO's top 10 holdings are 27% of its listed weight; VOO's are 58%. The more concentrated fund leans harder on its largest names.