IVV vs VO: how much do they really overlap?
IVV (iShares Core S&P 500 ETF, tracking the S&P 500) and VO (Vanguard Mid-Cap ETF, tracking the CRSP US Mid Cap) overlap by roughly 1% by weight. 0 of IVV's top 10 holdings also appear in VO. A 50/50 blend of the two behaves like about 183 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 1 holdings appear in both IVV and VO. The weight columns show how much of each fund each name represents.
| Holding | in IVV | in VO |
|---|---|---|
| MRVL MARVELL TECHNOLOGY INC | 0.40% | 0.89% |
Only in IVV
iShares Core S&P 500 ETF — US large-cap. Its biggest holdings that VO doesn’t have:
| NVDA NVIDIA CORP | 7.51% |
| AAPL APPLE INC | 6.58% |
| MSFT MICROSOFT CORP | 4.29% |
| AMZN AMAZON.COM INC | 3.61% |
| 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% |
Only in VO
Vanguard Mid-Cap ETF — US mid-cap. Its biggest holdings that IVV doesn’t have:
| STX Seagate Technology Holdings plc | 1.90% |
| WDC Western Digital Corp. | 1.78% |
| VRT Vertiv Holdings Co. Class A | 1.18% |
| PWR Quanta Services Inc. | 1.06% |
| HWM Howmet Aerospace Inc. | 1.03% |
| CMI Cummins Inc. | 0.89% |
| CEG Constellation Energy Corp. | 0.88% |
| SLB Schlumberger Ltd. | 0.81% |
So — essentially different. Should you hold both?
IVV and VO hold almost none of the same securities — they are complementary, not redundant. Held together they genuinely broaden your exposure — a 50/50 blend reaches ~183 effective positions (grade A), because they hold largely different securities.
Holdings as of — IVV: Jun 30, 2026 (iShares (BlackRock)); VO: May 31, 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 →IVV vs VO — FAQ
- How much do IVV and VO overlap?
- IVV and VO overlap by approximately 1% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 0 of IVV's 10 largest holdings are also held by VO. They share 1 of their listed top holdings in total.
- Is it redundant to hold both IVV and VO?
- 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 183 positions and a A diversification grade.
- What does VO hold that IVV doesn't?
- VO's largest holdings that IVV doesn't hold include STX, WDC, VRT, PWR, HWM. Its category is US mid-cap, versus IVV's US large-cap.
- Which is more concentrated, IVV or VO?
- IVV's top 10 holdings are 58% of its listed weight; VO's are 31%. The more concentrated fund leans harder on its largest names.