How to compare two ETFs
Comparing two ETFs on fee and past return compares the two things least likely to tell them apart. Start with what each one holds and how much of it is the same. Across the 4,950 pairs you can form from the 100 largest US equity ETFs, the median pair shares 3.5% of its weight — but 9.9% of pairs are more than half the same fund, as of August 25, 2026.
The five comparisons that do separate two funds are below, in the order they are worth running. The first four can differ enormously between two funds with almost identical fees.
Updated August 25, 2026
Five comparisons, in this order
- 1. What each holds, and how much is the same — the one that most often ends the exercise.
- 2. How concentrated each one is — the top-ten weight, not the number of holdings.
- 3. Growth and profitability of the companies inside.
- 4. Valuation — against peers, and against each fund's own past.
- 5. Cost, size and liquidity — a bar to clear, not a way to choose.
Why fee and past return are the wrong place to start
Both are easy to find, which is most of why they get used. Between two funds covering similar ground the expense-ratio gap is usually a few basis points, and past return describes a portfolio that has since changed — holdings turn over, index rules get revised, and the companies inside change shape. Neither number tells you whether the two funds are actually alternatives to each other.
That question — are these two funds alternatives, or the same bet twice — is answered by their holdings, and it has a number.
One live pair from each relationship, measured by weight across every holding.
| Pair | Shared weight | First in second | Second in first | What that is |
|---|---|---|---|---|
| IVV & VOO | 97% | 99.7% | 99.9% | Effectively the same fund |
| IVV & QQQ | 53.5% | 53.5% | 94.5% | One sits inside the other |
| QQQ & VGT | 52.1% | 55.4% | 77.1% | Less alike than they look |
| VTI & VXUS | 1.3% | 5.1% | 5.5% | Potential diversifiers |
The five comparisons, in order
What each holds, and how much of it is the same
Two funds sharing 70% of their weight are not two positions. Read overlap as a share of weight rather than a count of shared names, and read it in both directions — a focused fund can sit almost entirely inside a broad one while being a small slice of it, and a single symmetric figure hides which is which.
Same category is not the same fund. IJH and VO sit in the same category, and 0.6% of IJH's weight sits inside VO while 0.1% of VO is IJH — compare them side by side. Two funds filed under one label can hold largely different companies, which is exactly what a category average cannot tell you.
Where to find it: ETF Research Center's free overlap tool, and ETF Copilot's overlap page, which covers every pair daily rather than on request. More on the measurement itself: how much do two ETFs overlap?
How concentrated each one is
Holdings count is close to meaningless on its own; the weights decide. A 500-holding fund with 37% of its money in ten companies behaves like a concentrated fund. Compare the top-10 weight of each, not how many lines are in the file.
This is where two funds tracking "the same" index most often diverge: capping rules, float adjustments and equal weighting change the top of the book without changing the constituent list much at all.
Where to find it: top-10 weight is free on Yahoo Finance, Stock Analysis and ETFdb. ETF Copilot publishes it across the market on the concentration page.
Growth and profitability of what is inside
A fund has no revenue or margin of its own; both are the weighted aggregate of its holdings. Two funds with the same label can carry very different underlying growth rates and returns on equity, because they weight the same companies differently or hold a different tail.
Read each figure twice — against the other fund, and against where that fund has been historically. A fund whose underlying growth has halved while its peer's held steady is a different situation from both slowing together.
Where to find it: Morningstar computes portfolio-level growth metrics, ETF Research Center publishes return on equity, and ETF Copilot charts both against the market and the fund's own past.
Valuation, measured both ways
A fund's price-to-earnings ratio is the weighted average of its holdings'. Comparing the two funds' multiples is the easy half; the harder and more useful half is where each sits against its own past, because peers frequently re-rate together and a peer comparison alone cannot show that.
Where to find it: peer comparison free on ETFdb and ETF Research Center. The historical comparison is rare — is my ETF expensive? covers what it takes to build it.
Cost, size and liquidity
Last, and as a bar to clear rather than a way to choose. Is either fee grossly out of line with near-identical alternatives? Is either fund small enough to be at risk of closure? Does either trade thinly enough that the spread outweighs the fee gap? If all three are fine, the first four comparisons decide it.
Where to find it: every free site publishes expense ratio, assets and average volume, and so does each fund provider's own page.
What should I compare when choosing between two ETFs?
Holdings overlap first, then concentration, then the growth and profitability of the underlying companies, then valuation against both peers and the fund's own history, then cost and liquidity. The first comparison often ends the exercise: if two funds share most of their weight, the remaining differences are small by construction.
Do two ETFs in the same category hold the same things?
Frequently not. IJH and VO share 0.1% of their weight despite sitting in the same category, as of August 25, 2026. Category is a filing label; two funds under one label can differ in index rules, capping, weighting and the size of the tail they hold. The overlap figure is what settles it.
Is the cheaper ETF the better one?
Cheaper is cheaper; it is not a ranking. Among funds that hold materially different things, a few basis points of fee is small next to the difference in what you own. Among funds that hold nearly the same things, cost and tracking are most of what is left to separate them — which is a reason to measure overlap first, not a reason to lead with the fee.
How do I compare two ETFs' holdings?
Look for a figure expressed as a share of each fund's weight, reported separately for each direction, and computed across every holding rather than the top ten. A count of shared names, a single symmetric percentage, or a top-10 comparison will each understate how much two funds have in common.
How this is measured
The distribution above covers every one of the 4,950 pairs that can be formed from the 100 largest US-listed equity ETFs by assets. Overlap is the share of each fund's weight held in companies the other fund also holds, computed across every holding in both funds and updated daily; the figure charted is the symmetric one. Bucket edges are fixed, so the shape is comparable from one day to the next.
Compare two funds by what they hold →
ETF Copilot reports data factually. Nothing on this page is investment advice, a recommendation, or a forecast of returns. It describes how to read fund data, not what to do with it. Third-party capabilities were checked on each provider's own site on 24 August 2026.