Kenteli
How Kenteli measures overlap, and why the number can differ
Guide · 24 September 2026
Put the same two funds into several overlap checkers and you can get several different answers. That is not a sign that some of them are broken. It usually means they are answering different questions, and most of them do not say which question they picked.
Three questions that all get called "overlap"
Before any arithmetic, there is a choice to make.
- How many companies do both funds hold? A count of shared names. Easy to compute, and close to useless on its own, because a fund can hold a company at a tiny weight and it counts the same as a company held at five per cent.
- How much of this fund sits inside that one? Take every company in the first fund, keep the ones the second fund also holds, and add up their weight. This is the figure that reads naturally as a sentence: most of the first fund is already inside the second.
- How similar are the two, overall? A single score that compares the two weight profiles, so that two funds holding the same companies in very different proportions do not score as identical.
The second question has a property worth noticing: it is not symmetrical. A small, concentrated fund can sit almost entirely inside a huge broad one, while the broad one has only a fraction of itself in the small one. Both statements are true at once. A tool that reports a single number for the pair has quietly chosen one direction, or averaged them.
An illustration
Invented funds, invented weights, chosen to make the arithmetic visible. Imagine Fund A holds three companies and Fund B holds four.
| Company | Weight in Fund A | Weight in Fund B |
|---|---|---|
| Company one | 50% | 10% |
| Company two | 30% | 10% |
| Company three | 20% | 0% |
| Company four | 0% | 40% |
| Company five | 0% | 40% |
Two companies are shared, so a shared-name count says two out of five. The weight that Fund A has inside Fund B is 50 plus 30, which is 80 per cent. Going the other way, the weight Fund B has inside Fund A is 10 plus 10, which is 20 per cent. A similarity score, which takes the smaller of the two weights for each shared company, gives 10 plus 10, or 20 per cent.
Four defensible numbers from one pair of funds: two names, 80 per cent, 20 per cent, 20 per cent. Every one of them is arithmetically correct. This is the entire reason published overlap figures disagree.
What Kenteli reports, and why
Kenteli shows the shared count, both directions of containment, and a score out of one hundred, because no single number answers the question on its own. The containment figures are named in the direction they were computed, so a sentence like "most of this fund sits inside that one" says which fund is doing the sitting.
One detail that matters more than it sounds. Because reported holdings may not represent one hundred per cent of a fund's portfolio, Kenteli divides containment by the fund's own reported total holding weight rather than assuming the reported holdings add up to one hundred. A fund we can only see part of would otherwise look less overlapping than it is, precisely where the data is thinnest.
It also does the same look-through across an entire portfolio rather than one pair at a time, weighted by how much of each fund you actually hold. A pair of funds can overlap heavily and barely matter, if you hold very little of one of them.
The other reasons two tools disagree
- Different dates. Funds publish holdings on a schedule, and a measurement is only as current as the file it read. Two tools refreshed a week apart can differ for that reason alone.
- Different universes. Some tools compare only the top ten or top fifty holdings. A comparison of the top ten is a comparison of the top ten, not of the funds.
- Cash, bonds and other assets. A fund is rarely one hundred per cent equity. Whether the rest is dropped or kept in the denominator moves the answer.
- Share classes and identifiers. One company can appear under more than one line. Treating those as one company or two changes both the count and the weight.
- Rounding. Published weights are rounded, and hundreds of small roundings add up.
What the number is not
It is not advice, and Kenteli does not tell you to sell anything. A high overlap figure is a description of what you own, not a verdict on it. What you do about it depends on what you were trying to build, which is yours to decide.
If you want the plain-language version of the problem first, start with the other guide.