Learn · Holdings filed for periods June 30, 2026 to August 31, 2026
What does holdings overlap actually mean?
Data as of June 30, 2026 to August 31, 2026 holdings (filed July 20, 2026 to October 29, 2026)
Holdings overlap is the share of two portfolios that is the same, measured by weight. It answers whether two funds duplicate each other; active share answers whether one fund differs from its index.
We publish 35 curated fund pairs, each comparing two real portfolios from the same filing period rather than a category average. Those pairs are pinned to their own holdings run, covering 3 reporting periods, March 31, 2026 to May 31, 2026 — a different event from the registry figures elsewhere on this site, and dated separately for that reason.
The two measures are not the same question
- Overlap between two funds tells you whether owning both buys diversification or the same portfolio twice. Two S&P 500 funds overlap almost completely; owning both spreads nothing.
- Active share against an index tells you whether a fund’s fee is buying difference. It is a statement about one fund and its benchmark, not about two funds.
They can disagree in both directions. Two genuinely active funds can overlap heavily with each other while each differs from the index. Two funds can each track the index closely and so overlap heavily by construction.
| Holdings overlap | Active share | |
|---|---|---|
| Compares | Two funds with each other | One fund with its benchmark index |
| Answers | Am I buying the same portfolio twice? | Is this fee buying any difference? |
| High value means | The two funds largely duplicate each other | The fund differs substantially from its index |
| On this site | 35 curated pairs, holdings March 31, 2026 to May 31, 2026 | Every classified fund in the registry |
Reading the number honestly
Overlap is measured on a filing date, by weight, against the identifiers both funds disclose, and each of those three words carries a limit. Funds trade after they file, so a pair measured on one period’s holdings can look different on the next. Weight matters as much as the names: two funds holding identical securities at very different weights overlap far less than a shared holdings list suggests.
Matching is the one that bites hardest. Holdings that do not resolve to a security identifier cannot be compared at all, and where too little of a pair matched we report it as insufficient rather than publish a figure built on the half that did.
Why weights matter more than names
A shared holdings list is a weak signal. Two funds can hold thirty of the same companies and still behave very differently if one concentrates a third of its portfolio in three of them and the other spreads evenly across all thirty. Overlap measured by weight captures that; a count of shared names does not. It is the reason a fund factsheet listing “top ten holdings” can look reassuringly distinctive while the portfolios underneath are nearly the same.
The same effect runs the other way. Two funds with very different holdings lists can overlap substantially if both are dominated by the same handful of very large companies, which is common among US large-cap funds of any description.
What it is good for
The practical use is checking a portfolio for accidental duplication — two large-cap funds in the same account, or a fund that duplicates a core index holding. High overlap between two funds you both pay for means you are paying twice for one exposure, and the cheaper of the two is doing the same work.
High overlap is not automatically a problem. Two index funds tracking the same benchmark should overlap almost completely; that is them working correctly, and the only question worth asking is which one costs less. Overlap becomes interesting when you are paying different prices for substantially the same portfolio, or when you believed you were diversifying and the holdings say otherwise.
Checking your own holdings
The quickest version of this check needs no tools. List the equity funds you hold, write down the benchmark each one names in its prospectus, and group them. Any two funds naming the same benchmark are candidates for heavy overlap, and the one charging more has to be doing something visibly different to earn the gap. Funds naming different benchmarks can still overlap if those benchmarks themselves do, which is usually true of broad US indices.
Where a pair looks suspicious, the pair pages here give the measured figure rather than the inference. Where a pair is not covered, the same comparison can be made from the funds’ own filed holdings, which are public.
What you do with a high number is a separate judgement. Consolidating into the cheaper of two near-identical funds is often sensible, but in a taxable account the tax owed on selling can exceed years of the fee difference, and that calculation is specific to you.
Next: the overlap pair index, or what active share measures.