ETF Overlap Tool: Compare Holdings Across 2–4 ETFs
This ETF overlap tool shows how much two to four funds have in common: the holdings they share, the overlap by weight, and what each fund holds on its own. Paste each fund's holdings below to calculate ETF overlap in your browser, or compare USD-listed ETFs with sourced holdings data in PWW.
Overlap matters because two funds with different names can still hold many of the same companies. Jump to the calculator, or read on for how the numbers work.
ETF overlap calculator
Paste the holdings of two to four funds, for example from each issuer's published holdings file. Everything is calculated in your browser: nothing you paste is sent to PWW or stored.
One holding per line: ticker, weight % (for example MSFT, 6.5). Up to 1,000 lines per fund. Use the same ticker format for both funds; a header line is skipped.
Overlap result
Showing an example with hypothetical weights, not the holdings of any real ETF. Paste holdings for every fund to see your own result.
- Overlap by weight
- 65.00%
- Sum of the smaller weight of each shared holding.
- Shared holdings
- 4
- 50% of Fund A's holdings · 57% of Fund B's holdings
- Weights entered: Fund A 100.00% · Fund B 100.00%
| Ticker | Fund A | Fund B | Shared |
|---|---|---|---|
| AAPL | 20.00% | 20.00% | 20.00% |
| MSFT | 18.00% | 22.00% | 18.00% |
| NVDA | 15.00% | 18.00% | 15.00% |
| AMZN | 12.00% | 14.00% | 12.00% |
| JPM | 10.00% |
|---|---|
| XOM | 9.00% |
| JNJ | 8.00% |
| PG | 8.00% |
| GOOGL | 12.00% |
|---|---|
| META | 10.00% |
| AVGO | 4.00% |
How the ETF overlap tool calculates overlap
The calculator reports overlap by weight and by count. They answer different questions, so it is worth looking at both. With three or four funds it adds a third measure.
| Measure | How it is calculated | What it tells you |
|---|---|---|
| Overlap by weight | For each holding in both funds, take the smaller of its two weights, then add those up | How much of each fund is invested in the same companies |
| Overlap by count | Number of shared holdings divided by each fund's total number of holdings | How many names the funds share, regardless of position size |
| Overlap held by every fund (3–4 funds) | For each holding that all selected funds own, take the smallest of its weights, then add those up | How much every fund has invested in the same companies |
Take the example in the calculator, which uses hypothetical weights. Both funds hold AAPL, MSFT, NVDA, and AMZN. The smaller weights are 20%, 18%, 15%, and 12%, so overlap by weight is 65%. Those four shared names are 50% of Fund A's eight holdings and about 57% of Fund B's seven.
Comparing three or four ETFs
Add a third or fourth fund and the calculator switches to two views. A pair table shows overlap by weight for every pair, so you can see which two funds overlap the most. A second table lists only the holdings that every selected fund owns, with each fund's weight and the smallest of them. A holding owned by three of four funds appears in the pair table but not in the every-fund list.
Weight usually matters more than count. Two broad funds can share hundreds of small positions and still have modest overlap by weight, while two concentrated funds can share only a few large positions and overlap heavily.
How to read your ETF overlap results
- High overlap by weight: a large part of both funds sits in the same companies, so holding both adds less diversification than it may appear.
- Low overlap by weight: the funds are invested in mostly different companies and complement each other more.
- High count overlap but low weight overlap: the funds share many names, but the shared positions are small in at least one of them.
- Weights that don't add up to 100%: holdings files often include cash, futures, or rounding. The calculator uses the weights as entered and shows the totals so you can see the gap.
- Different dates: compare files from the same date where possible, because holdings change.
Overlap describes what you own. It does not say whether you should keep, add to, or sell either fund.
Why ETF overlap matters for your portfolio
- Hidden concentration. Many index funds hold the same large companies near the top. Owning several of them can leave you more concentrated in those companies than you intended.
- Sector and style tilts. Overlap often comes from one sector or market segment, which can tilt a portfolio that looks diversified by fund count.
- Paying for similar exposure twice. If two funds largely overlap, you may be paying two expense ratios for similar exposure.
Diversification is about spreading risk across holdings that behave differently. The SEC's investor education site explains diversification and asset allocation if you want the background.
Where to get ETF holdings data
Most US ETFs make their holdings easy to find. Under the SEC's ETF rule, an exchange-traded fund relying on it must disclose its portfolio holdings prominently on its website each business day (Rule 6c-11(c)(1)). To use the calculator:
- Open each fund's page on its issuer's website.
- Download or copy the holdings list.
- Keep two columns: ticker and weight as a percent of the fund.
- Paste each list into Fund A and Fund B above.
- Note the as-of date on each file.
For a plain-language overview of how ETFs work, see Investor.gov's ETF glossary entry and FINRA's guide to exchange-traded funds and products.
Compare ETFs with sourced data in PWW
Pasting files works for a quick check. If you review the same funds regularly, PWW keeps the data and its sources together.
| This calculator | ETF comparison in PWW | |
|---|---|---|
| Holdings data | Whatever you paste in | Fund information and holdings from its data source, with source details shown |
| Funds per comparison | Two to four | Two to five USD-listed ETFs |
| Account | None needed; nothing is sent or stored | Free account; Pro adds ETF look-through for your own portfolio |
| Hong Kong-listed ETFs | Yes, if you paste their holdings | Not covered yet |
Create a free PWW account to compare ETFs, see what each plan includes, or read where PWW's data comes from and its limits. If you are tempted to ask a chatbot instead, read what a ChatGPT investment portfolio review can and can't check first.
Frequently asked questions
What is ETF overlap?
ETF overlap is how much two or more funds hold the same companies. It is usually measured by weight: for each shared holding, take the smaller weight and add them up. An ETF overlap tool calculates this and lists the shared holdings, so you can check whether owning several funds actually adds diversification.
How is ETF overlap calculated?
Overlap by weight takes the smaller of the two weights for every holding both funds own and adds them up. Overlap by count divides the number of shared holdings by each fund's total number of holdings. This tool shows both, because they can tell very different stories.
What is a good ETF overlap percentage?
There is no universal threshold. If you hold two funds to spread your money across different companies, lower overlap by weight means they complement each other more. If you hold them for other reasons, such as cost or tax, higher overlap may be acceptable. The number describes your holdings; it is not a recommendation.
Is this ETF overlap tool free?
Yes. The calculator on this page is free and needs no account. Comparing ETFs with sourced holdings data inside PWW needs a free account, and ETF look-through for your own portfolio is part of the Pro plan.
Can I compare more than two ETFs?
Yes. Add up to four funds to the calculator. It shows overlap by weight for every pair and lists the holdings that all selected funds own. Inside PWW, you can compare 2 to 5 USD-listed ETFs that its data source covers; Hong Kong-listed ETFs are not covered there yet.
How current is the holdings data?
The calculator uses whatever you paste in, so the result is only as current as that file. Many US ETFs publish their holdings every business day; check the date on the file before you rely on the result. Inside PWW, each comparison shows its source details and when the data was fetched.
This page is for education only and is not investment advice. The calculator works only on the data you enter. See the privacy policy and terms of service, or go back to the PWW home page.