ETF Overlap Calculator
Compare ETF ticker lists, find shared names, and measure pairwise containment without treating it as a full portfolio analysis.
Earlier editorial review
- Reviewed
- 2026-09-25
- Methodology
- 1.1
Sources
How it works
Add two to four funds. Search can try to fill a ticker list from the local bundled snapshot. You can also paste or edit a comma separated identifier list. Identifiers may contain up to 64 characters, but cannot contain spaces or commas. An empty or invalid list makes the comparison unavailable instead of producing a zero result.
For every complete pair, the result shows the shared tickers and the percentage of the smaller unique list contained in the larger list. The summary is the equal weight mean of those pair results.
Read the lists and pair details before the average. A complete smaller list can be fully contained in a larger list even when the funds have different weights and many unlisted holdings.
Use the same disclosure date and comparable coverage for each fund. The local snapshot contains ticker names only and does not state when it was updated or whether it is complete.
Step by step
- Enter two to four ETF tickers.
- Paste or review the holdings ticker list for every fund.
- Compare shared names, pair percentages, and their simple average.
Worked example
List A has AAPL, MSFT, GOOGL, and AMZN. List B has AAPL, MSFT, and AMZN. The three shared tickers are the entire smaller list, so containment is 100%.
This compares ticker names only. It does not say that the funds have the same weights or that either list contains every holding in the fund.
When to use this calculator
Use this tool to see which ticker names repeat across two to four ETF holdings lists and whether a smaller list is contained in a larger one.
Compare fund weights, coverage dates, fees, factors, and account details separately. This ticker list measure does not replace those comparisons.
Common mistakes
Do not compare one complete current holdings file with an older short list for another fund. Differences in dates and coverage can change the result.
Do not treat zero shared tickers as proof of low correlation, or 100% containment as identical fund weights or full holdings.
Formula
For each pair of ETFs A and B:
Set A = unique normalized tickers in A
Set B = unique normalized tickers in B
Pair overlap (%) = shared ticker count / min(size of A, size of B) × 100
Average pairwise overlap (%) = arithmetic mean of every pair overlap
Empty or incomplete ETF lists make the result unavailable. Identifiers are trimmed, uppercased, limited to 64 characters, and cannot contain commas or whitespace. Repeated identifiers in one list count once. The smaller list is the denominator, so the measure is containment, not weighted portfolio similarity.
Assumptions and limits
The calculation uses entered identifiers only. It ignores holding weights, cash, derivatives, share classes, duplicate listings, unmatched securities, and names missing from the entered lists. It does not calculate weighted overlap, correlation, diversification, or portfolio concentration. Identifiers are limited to 64 characters and cannot contain commas or whitespace. The displayed bands are illustrative ranges only. Bundled ticker snapshots are not guaranteed to be current or complete.
Key terms
- Shared ticker
- A normalized ticker name that appears in both entered lists.
- Pairwise containment
- The proportion of the smaller unique ticker list that also appears in the larger list.
- Pairwise average
- The arithmetic mean of the pairwise containment percentages, with equal weight for each pair.
Related calculations
Use the ETF expense ratio calculator to compare fund costs. Use the portfolio rebalancer to examine allocation changes after checking repeated tickers.
Portfolio beta estimates market sensitivity, which ticker overlap does not measure. Funds with few shared names can still respond similarly to market movements.
FAQ
What does ETF overlap show?
A ticker list can show repeated names across funds. It cannot show how much of your money is exposed to each name or whether the funds have similar risks. The result depends on the lists you provide.
How is pairwise overlap calculated?
The tool normalizes ticker case and removes duplicate tickers within each list. For each pair, it divides the number of shared tickers by the size of the smaller unique list. A result of 100% means that smaller list is contained in the larger one.
What does the average mean?
The summary is the arithmetic mean of all pairwise percentages. Every pair has equal weight, whether there are three pairs or six. The summary is not weighted by fund size or holding weights.
Are the low, moderate, and high bands investment ratings?
The bands are interface ranges only: below 40%, from 40% to below 70%, and 70% or more. They are not risk grades, official standards, or recommendations about a suitable portfolio.
Where should I get holdings data?
Use each fund issuer’s holdings disclosure and align the disclosure dates. A short list such as the top ten holdings may omit shared names elsewhere in the fund. The bundled examples are a local ticker snapshot with no freshness or completeness guarantee.
Related tools
Compare fund costs with the ETF expense ratio calculator. Examine allocation changes with the portfolio rebalancer. Use portfolio beta for a separate market sensitivity measure.