ITOT vs VOO: how much do they really overlap?
ITOT (iShares Core S&P Total US Stock Market ETF, tracking the S&P Total Market) and VOO (Vanguard S&P 500 ETF, tracking the S&P 500) overlap by roughly 94% by weight. 10 of ITOT's top 10 holdings also appear in VOO. A 50/50 blend of the two behaves like about 58 equally-weighted bets (diversification grade B). In short, the two funds hold nearly the same stocks in nearly the same proportions — owning both is largely redundant.
The same companies, in both funds
These 46 holdings appear in both ITOT and VOO. The weight columns show how much of each fund each name represents.
| Holding | in ITOT | in VOO |
|---|---|---|
| AAPL APPLE INC | 6.78% | 6.59% |
| NVDA NVIDIA CORP | 6.54% | 7.51% |
| MSFT MICROSOFT CORP | 4.64% | 4.30% |
| AMZN AMAZON.COM INC | 3.19% | 3.62% |
| GOOGL ALPHABET INC CLASS A | 2.71% | 3.25% |
| AVGO BROADCOM INC | 2.54% | 2.77% |
| GOOG ALPHABET INC CLASS C | 2.18% | 2.59% |
| META META PLATFORMS INC CLASS A | 1.64% | 1.92% |
| MU MICRON TECHNOLOGY INC | 1.36% | 2.02% |
| JPM JPMORGAN CHASE & CO | 1.30% | 1.26% |
| LLY ELI LILLY | 1.26% | 1.47% |
| TSLA TESLA INC | 1.20% | 1.84% |
| AMD ADVANCED MICRO DEVICES INC | 1.09% | 1.47% |
| JNJ JOHNSON & JOHNSON | 0.85% | 0.95% |
| V VISA INC CLASS A | 0.84% | 0.87% |
+ 31 more shared holdings.
Only in ITOT
iShares Core S&P Total US Stock Market ETF — total US market. Its biggest holdings that VOO doesn’t have:
| BRKB BERKSHIRE HATHAWAY INC CLASS B | 1.30% |
| XOM EXXONMOBIL HOLDINGS CORP | 0.90% |
| TMO THERMO FISHER SCIENTIFIC INC | 0.30% |
| AMGN AMGEN INC | 0.29% |
Only in VOO
Vanguard S&P 500 ETF — US large-cap. Its biggest holdings that ITOT doesn’t have:
| BRK.B Berkshire Hathaway Inc. Class B | 1.42% |
| SNDK Sandisk Corp. | 0.52% |
| IBM International Business Machines Corp. | 0.41% |
| MRVL Marvell Technology Inc. | 0.40% |
So — nearly identical. Should you hold both?
ITOT and VOO hold nearly the same stocks in nearly the same proportions — owning both is largely redundant. If you already hold ITOT, adding VOO mostly increases your bet on the names they share rather than spreading it — a 50/50 blend still behaves like only ~58 equal positions, with the top 10 alone at 35% and the Magnificent Seven at 30%.
Holdings as of — ITOT: Jul 30, 2026 (iShares (BlackRock)); 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 →ITOT vs VOO — FAQ
- How much do ITOT and VOO overlap?
- ITOT and VOO overlap by approximately 94% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 10 of ITOT's 10 largest holdings are also held by VOO. They share 46 of their listed top holdings in total.
- Is it redundant to hold both ITOT and VOO?
- Because they hold nearly the same stocks in nearly the same proportions — owning both is largely redundant, holding both is largely redundant — you mostly duplicate the same megacaps and concentrate rather than diversify. A 50/50 blend has an effective 58 positions and a B diversification grade.
- What does VOO hold that ITOT doesn't?
- VOO's largest holdings that ITOT doesn't hold include BRK.B, SNDK, IBM, MRVL. Its category is US large-cap, versus ITOT's total US market.
- Which is more concentrated, ITOT or VOO?
- ITOT's top 10 holdings are 59% of its listed weight; VOO's are 58%. The more concentrated fund leans harder on its largest names.