ETF overlap checker

ETF overlap is the share of one fund made of the same companies as another fund. Two ETFs with different names, providers and indexes can still hold the same stocks. An MSCI World ETF and an S&P 500 ETF are the classic example: around 70% of the MSCI World index is US companies, so both funds put their largest weights in Nvidia, Apple, Microsoft and Amazon.

Owning both feels like diversification, but much of the money ends up in the same handful of companies. The checker above shows how much of that is happening in the ETFs you pick.

The weighted overlap counts how much of each fund sits in shared companies. For every company held by both ETFs, the checker takes the smaller of its two weights and adds them up. If Apple is 4.7% of one fund and 6.8% of the other, 4.7 points count as overlap. A result of 0% means the funds share none of their top holdings, and the higher the number, the more the two funds move together.

With 3 or 4 ETFs, the pair table shows the overlap of every pair, and the headline shows the most similar pair. The shared holdings table lists each company held by at least 2 of your ETFs, its weight in each fund, and its share of a portfolio split equally across all of them. That last column is your real exposure to the company if you put the same amount in each ETF.

High overlap is not a mistake in itself. If you hold an S&P 500 fund on purpose to tilt toward the US, the overlap with your world ETF is the point. The problem is overlap you did not choose: a tech ETF, a US ETF and a world ETF together can make a few mega caps a much larger part of your portfolio than any single fund suggests.

Knowing the overlap helps you decide whether a new ETF adds something different or just more of what you already own. It also helps you simplify: if two funds overlap heavily, keeping only the cheaper one often changes little in your exposure and cuts costs and paperwork.

The checker weighs every ETF equally, because you have not told it how much you hold. If you have 90% in one fund and 10% in another, your real exposure to the shared companies follows the large fund much more closely. The weighted overlap between two funds does not depend on amounts, but the equal split column does.

The data covers each ETF's top 10 holdings, which are often 20% to 40% of a broad fund. Shared companies outside the top 10 are not counted, so the real overlap is usually higher than shown. Companies are matched by ticker or ISIN, and holdings are refreshed from time to time, so recent index changes may not show yet.