Wealthy PotITOT vs VOO: 2,460 Stocks or 500, and 88% of ITOT Is the S&P 500
ITOT is iShares' total US stock market ETF. VOO is Vanguard's S&P 500 ETF. Both charge 0.03%, and most of ITOT is the S&P 500 anyway. ITOT's own prospectus says the S&P 500 made up about 88% of its index at 31 March 2026. Our match of the two funds' 30 June 2026 SEC filings agrees: 88.1% overlap, with every VOO holding also in ITOT. ITOT's other 1,931 positions, the mid, small and micro caps, came to 11.7% of the fund. Over the ten years to 30 June 2026 VOO returned 15.47% a year and ITOT 15.01%. Choose VOO if you want large US companies only. Choose ITOT if you want the whole market in one fund. Holding both adds almost nothing.
Table of Contents
The Short Answer
- Fees: a tie at 0.03%. Both prospectuses show $3 after one year and $39 after ten on $10,000.
- Overlap: 88.1%. 88.1% of ITOT's weight was in VOO stocks, and 99.7% of VOO's weight was in ITOT stocks. Both filings are dated 30 June 2026.
- Holdings: 2,460 vs 505. iShares' page, 2 October 2026; Vanguard's data, 31 August 2026.
- Ten-year return to 30 June 2026: VOO 15.47%, ITOT 15.01% a year at NAV. VOO also led over five years (13.36% vs 12.24%). ITOT led over one year (23.05% vs 22.28%).
- Same index company. ITOT tracks the S&P Total Market Index, which is the S&P 500 plus the S&P Completion Index. VOO tracks the S&P 500.
- Pick one. VOO is already inside ITOT, so owning both just tilts you slightly further toward large caps.
How Much of ITOT Is Already VOO
ITOT's July 2026 summary prospectus describes its index as "the common equities included in the S&P 500® and the S&P Completion Index™," and adds that at 31 March 2026 those two parts held "approximately 88% and 12%, respectively," of the index's market value. So by construction, ITOT is an S&P 500 fund with a 12% side order of smaller companies.
| SEC portfolio filings, 30 June 2026 | ITOT | VOO's fund |
|---|---|---|
| Holdings in the filing | 2,432 | 501 |
| Held by both funds | 501 | 501 |
| Share of the fund in those shared holdings | 88.1% | 99.7% |
| Holdings the other fund did not own | 1,931 (11.7% of ITOT) | 0 |
| Overlap, sum of the smaller weight in each shared stock | 88.1% | |
The big names are the same, a little smaller in ITOT. NVIDIA was 6.63% of ITOT and 7.51% of VOO; Apple 5.81% and 6.59%; Alphabet 5.15% and 5.84%; Microsoft 3.79% and 4.30%. Every S&P 500 stock is diluted by about an eighth in ITOT, because the smaller companies take up the rest.
The 1,931 extra companies are tiny one by one. The largest in the filing were Space Exploration Technologies (0.14% of ITOT), Snowflake (0.12%), Bloom Energy and Cloudflare (0.11% each). Together the whole group was 11.7%, about one dollar in eight and a half. That is all the "total market" part of ITOT adds.
ITOT vs VOO Side by Side
| ITOT | VOO | |
|---|---|---|
| Full name | iShares Core S&P Total U.S. Stock Market ETF | Vanguard S&P 500 ETF |
| Index | S&P Total Market Index | S&P 500 |
| Company size | Large, mid, small and micro caps | Large caps |
| Expense ratio | 0.03% | 0.03% |
| Prospectus cost on $10,000, 10 years | $39 | $39 |
| Holdings | 2,460 (2 Oct 2026) | 505 (31 Aug 2026) |
| Indexing method | Representative sampling | Replication |
| Top ten positions (30 Jun 2026) | 33.4% (our count from the filing) | 37.9% (Vanguard fact sheet) |
| Turnover (latest fiscal year) | 3% | 2% |
| Assets | $96.9bn (2 Oct 2026) | ETF class $1.0 trillion; whole fund $1.8 trillion (31 Aug 2026) |
| Inception | 20 Jan 2004 | 7 Sep 2010 |
| Exchange | NYSE Arca | NYSE Arca |
What the Extra Stocks Have Been Worth
| Average annual, NAV, to 30 Jun 2026 | 1 year | 3 years | 5 years | 10 years |
|---|---|---|---|---|
| ITOT | 23.05% | 20.43% | 12.24% | 15.01% |
| S&P Total Market Index | 23.07 | 20.42 | 12.24 | 15.01 |
| VOO | 22.28% | 20.58% | 13.36% | 15.47% |
| ITOT minus VOO | +0.77 | -0.15 | -1.12 | -0.46 |
Both funds tracked their indexes almost exactly, so the gap is the index gap. Because ITOT is 88% S&P 500, its result is the S&P 500's result blended with the 12% of smaller companies. When smaller companies lag, ITOT trails VOO a little; when they lead, ITOT edges ahead. Over five and ten years they lagged, so VOO was ahead. Over the latest year they did slightly better, and ITOT was ahead.
The prospectuses show the same pattern for calendar 2025: ITOT returned 17.02% and VOO 17.84%. Over ten years to 31 December 2025 the figures were 14.21% and 14.78% a year.
$10,000 at VOO's ten-year rate to 30 June 2026 would have grown to about $42,140, and at ITOT's to about $40,491. (Hypothetical arithmetic on the published ten-year rates, ignoring taxes and trading costs. Not a forecast.) Which slice leads over the next decade is not something either filing predicts.
Where They Really Differ
- Coverage. ITOT gives you every size of US company. VOO gives you the roughly 500 large companies in the S&P 500. If you want mid and small caps without a second fund, that is ITOT's job.
- Concentration. VOO's top ten holdings were 37.9% of the fund at 30 June 2026. ITOT's top ten were about 33.4% in its filing, because the same giants are diluted by the smaller stocks. Still heavily weighted toward the largest companies either way.
- How they copy the index. ITOT uses representative sampling, so it does not hold every tiny stock in its index. VOO holds essentially all 500. ITOT matched its index over the ten years to 30 June 2026, and VOO trailed the S&P 500 by 0.04 points a year over the ten years to 30 September 2026.
- Issuer. ITOT is BlackRock's iShares; VOO is Vanguard's. Most large brokers trade both commission-free.
- Taxes. Both are ETFs with very low turnover (3% and 2%). The after-tax figures in their prospectuses moved with their pre-tax returns: ten-year after-tax-on-distribution returns to 2025 of 13.74% for ITOT and 14.32% for VOO.
Which One Fits You
Want one fund for the whole US market? ITOT. You get the S&P 500 plus about 12% in mid and small caps, at the same fee.
Want large companies only, or already hold a separate mid- or small-cap fund? VOO. Adding ITOT on top of a small-cap fund would double up on the smaller companies. Our VO vs VOO page shows how a mid-cap fund pairs with VOO.
Your 401(k) offers an S&P 500 fund and you have an IRA too? A common pattern is the S&P 500 fund at work and a total-market or extended-market fund elsewhere. Just do not buy ITOT in the IRA expecting much diversification on top of the S&P 500; it is 88% the same thing.
Already own one? In a taxable account, selling to switch can realize gains. With 88% overlap and the same fee, switching rarely pays for that.
Comparing the closest substitutes? ITOT's twin is VTI (ITOT vs VTI), and VOO's twin is IVV (IVV vs VOO). The same total-market-or-S&P choice at Vanguard is VTI vs VOO, and at Schwab SCHB vs VOO.
This is educational information, not personalized investment advice. Past performance does not guarantee future results, and all investing carries the risk of loss.
Sources & Methodology
- ITOT summary prospectus, 31 July 2026: objective, index definition and the 88%/12% split, fee table, cost example, sampling, turnover, returns to 31 December 2025.
- VOO summary prospectus, 28 April 2026: index, fee table, cost example, turnover, returns to 31 December 2025.
- iShares ITOT page: holdings count, assets, returns to 30 June 2026.
- VOO fact sheet as of 30 June 2026 and Vanguard's VOO profile: returns, top ten, holdings, assets.
How the overlap was computed. Our Portfolio Overlap Checker reads each fund's Form N-PORT holdings and adds up the smaller of the two weights for every shared holding. Both filings are for the period ended 30 June 2026, so the dates match.
What we did not verify. iShares had not yet published ITOT's 30 September 2026 quarter-end returns on its page when we checked, so the return table uses 30 June 2026 for both funds. We did not compare yields, because we did not have both funds' SEC yields for the same date.
This article is for general education and is not investment, tax or legal advice. Fund data changes daily, index returns cannot be invested in directly, and past performance does not guarantee future results. Figures were checked against the sources above on 5 October 2026; confirm current figures with iShares and Vanguard before acting.
FAQ: ITOT vs VOO
Is ITOT or VOO better?
Neither in general. Same 0.03% fee, 88.1% overlap. VOO returned more over ten years to 30 June 2026 (15.47% vs 15.01% a year) because large caps beat smaller ones. ITOT gives broader coverage.
How much do ITOT and VOO overlap?
88.1%, from both funds' 30 June 2026 SEC filings. Every VOO holding is in ITOT; ITOT's other 1,931 holdings were 11.7% of the fund.
Does ITOT include the S&P 500?
Yes. Its index is the S&P 500 plus the S&P Completion Index, and its prospectus puts the S&P 500 at about 88% of the index's value.
Should I own both ITOT and VOO?
There is little point. Together they behave like a total-market fund with a slight extra tilt to large caps. If you want more mid or small caps, add a fund that holds only those.
Which has lower fees?
Neither. Both charge 0.03%, or $39 over ten years on $10,000 in the prospectus examples.
Which is better for a Roth IRA?
Either works. Pick on coverage: ITOT for the whole market, VOO for large caps only.
Is ITOT the same as VTI?
Close. Both are 0.03% total-market ETFs from different index providers. See ITOT vs VTI.
Cite This Page
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"ITOT vs VOO: 2,460 Stocks or 500, and 88% of ITOT Is the S&P 500." Wealthy Pot, 2026. https://wealthypot.com/itot-vs-voo/
Related comparisons: ITOT vs VTI · IVV vs VOO · VTI vs VOO · SCHB vs VOO · VO vs VOO · All ETF comparisons
