VOO And VTI Hold About A Third In 10 Stocks: Concentration And Overlap Across 1,366 US Equity Etfs

(MENAFN- ValueWalk) The broad index fund at the core of a portfolio is about as concentrated as the typical equity ETF, and the funds around it often hold the same companies.

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The core sits in the middle of the range Then the funds start to overlap The common thread is the Mag 7 Measure the lineup before calling it diversified

VTI owns almost seven times as many companies as VOO. Its ten largest holdings still make up 33% of the fund, against VOO's 37%. By this measure, thousands of extra names buy very little diversification.

Most allocators treat a broad index ETF as the diversified core of a portfolio and spend their scrutiny on the satellites. Index concentration makes that core worth a second look. S&P Dow Jones Indices noted in May that the 10 largest companies in the S&P 500 made up almost 40% of the index by mid-2025, a level last seen in the mid-1960s.

For a portfolio, two narrower questions follow: how concentrated is each fund we own, and how much do our funds duplicate each other? The funds' own disclosures answer both. Under SEC Rule 6c-11, every ETF posts each holding, with its percentage weight, on its website before the open each business day. We computed both measures across the 1,366 US equity ETFs we track, using every holding in each fund, with data as of 10 November 2026.

The core sits in the middle of the range

Start with top-10 share, the weight a fund keeps in its ten largest positions. The typical US equity ETF holds 35% there and needs 20 holdings to reach half its weight.

The range around that middle is wide. At one end sits MSOS, a cannabis fund with all of its weight in its top ten. At the other are equal-weight and small-cap funds such as RSP, GSEW and SCHA, at 3%.

Broad core funds sit close to the typical fund. VOO is slightly above it and VTI slightly below, which is why holdings count tells an allocator so little: a fund can own thousands of stocks and still keep a third of its money in ten of them.

Top-10 share across 1,366 US equity ETFs, 10 November 2026. Source: ETF Copilot.

Top-10 share	Value
Typical US equity ETF	35%
Holdings the typical fund needs to reach half its weight	20
Share of the typical fund's holdings that carry half its weight	19%
Funds with more than half their weight in the top ten	311
Funds with less than 20% in the top ten	323
MSOS (most concentrated)	100%
RSP, GSEW, SCHA	3%
VOO (504 holdings)	37%
VTI (3,432 holdings)	33%

Then the funds start to overlap

Stack a few funds together and a second issue appears: they often own the same companies. We measure overlap in both directions, how much of fund A's weight sits in companies fund B also holds, and the reverse. The two figures part ways when funds differ in breadth or weighting, and the gap between them carries the finding.

Across all possible fund pairs, 590 are more than 90% identical by weight.

The best-known pairs show the pattern. VOO and VTI share 502 holdings, and more than 99% of VOO already sits inside VTI. QQQ is 93% inside VOO, so adding it to an S&P 500 core mostly raises the weight of names the core already holds.

Labels can mislead the other way too. SCHD and VIG are both US dividend funds, yet 58% of SCHD sits inside VIG and only 15% of VIG inside SCHD. VTV and VUG, Vanguard's value and growth funds, share 2% of their weight.

Overlap by weight, 10 November 2026. Across all possible fund pairs, 590 are more than 90% identical and 73 more than 99%. Source: ETF Copilot.

Pair	First fund inside second	Second fund inside first	Shared weight
VOO and VTI	over 99%	89%	89%
QQQ and VOO	93%	52%	52%
SCHD and VIG	58%	15%	15%
VTV and VUG	2%	2%	2%

A three- or four-fund lineup can therefore carry far less independent exposure than its line count suggests. The SEC's investor education site makes the same point:“even if you hold several mutual funds or ETFs and think you are diversified, you should check the top holdings of the funds to make sure they are different and provide the diversification you are seeking.”

The common thread is the Mag 7

Mega-cap technology runs through both measures. Of the funds we track, 453 hold at least one Magnificent 7, or Mag 7, stock, and their average Mag 7 weight is 20%.

The exposure reaches well past growth funds. Options-income (covered-call) funds average 22% Mag 7, close to the 24% of US total-market funds. An investor who adds a covered-call fund for income next to a total-market core may be adding weight to the same Mag 7 companies.

Mag 7 exposure across 1,366 US equity ETFs, 10 November 2026. Source: ETF Copilot.

Mag 7 weight	Value
MGK (highest)	58%
US large-cap growth funds, average	34%
VOO	33%
US total-market funds, average	24%
Options-income (covered-call) funds, average	22%
All 453 funds holding any Mag 7 stock, average	20%
Funds more than 25% Mag 7	171
Funds more than 40% Mag 7	41

Measure the lineup before calling it diversified

Concentration is a property of a fund, and S&P DJI's own historical work describes“a nuanced relationship between concentration and market performance.” What the numbers support is measuring a lineup before labeling it diversified:

Read top-10 share alongside holdings count. A 3,000-stock fund and a 500-stock fund can sit within a few points of each other. Read overlap in both directions. A single overlap percentage hides the case where one fund sits almost entirely inside another. Look through to common exposures. Add up Mag 7 or sector weight across every fund in the portfolio, including income and factor sleeves. Re-check on a schedule. Concentration drifts with prices, so a lineup balanced a year ago can look different today.

The daily holdings files that Rule 6c-11 requires make all four checks possible from public data, posted every morning before the open. The work is reading them across the whole lineup at once, because that is where the client's money sits.

Figures are computed by ETF Copilot from each fund's full published holdings, rebuilt nightly. The full top-10 distribution and the most and least concentrated funds are on the ETF Copilot concentration page.

Sources: S&P Dow Jones Indices, In the Shadows of Giants (Tim Edwards and Nick Didio, 13 May 2026); SEC Rule 6c-11; Investor, Asset Allocation and Diversification.

Written by the ETF Copilot research team. Data as of 10 November 2026. ETF Copilot has no business relationship with, and receives no compensation from, the issuers of the funds mentioned. Managers of ETF Copilot may or may not hold positions in the funds mentioned. Not investment advice.

About the author

The ETF Copilot Research Team publishes independent data on US-listed equity ETFs. It computes holdings overlap, look-through concentration and valuation against each fund's own history from each fund's published holdings, rebuilt nightly across 1,366 funds, and publishes the results as free reference pages with a citation line on each. ETF Copilot does not manage money or give investment advice. etf-copilot

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