ETF overlap: Swiss portfolio checklist

In short: owning several ETFs does not automatically create diversification. Compare their indexes, complete holdings, country weights and sector weights; then measure how much each duplicated position contributes to the total portfolio.

Start with the index names

Two funds with different marketing names can track indexes built from similar large companies. Record the exact benchmark, index provider, share class, fund domicile and replication method from each factsheet. Do not infer exposure from the ticker alone.

A global equity ETF and a U.S. large-cap ETF, for example, may both allocate heavily to the same companies. Adding the second fund can be an intentional tilt, but it should not be described as new diversification.

Compare complete holdings, not only the top ten

The top-ten table is a fast warning signal, not a full overlap calculation. Download the latest holdings file from each fund provider when available. Standardise company identifiers and remember that one issuer can appear through different share classes or listings.

For a quick review, mark holdings present in more than one fund. For a portfolio-level review, multiply each fund's holding weight by that fund's weight in your portfolio. This reveals the effective exposure rather than the overlap inside an isolated factsheet.

Check country and sector duplication

Overlap is not limited to identical securities. Two ETFs may hold different companies while concentrating on the same country, industry or risk factor. Compare regional allocation, sector allocation and index concentration alongside the security list.

Swiss investors should also separate economic exposure from trading currency. A fund listed on a Swiss venue can still hold mostly foreign assets. Listing venue does not turn global company exposure into Swiss exposure.

Decide whether the overlap has a job

Duplication is not automatically an error. A deliberate allocation to Swiss equities, small companies or a specific factor can express a documented portfolio choice. The problem is accidental duplication that adds complexity without changing the intended risk.

Write one sentence for each ETF: core global exposure, Swiss home allocation, bonds, emerging markets or another explicit role. If two funds have the same role and similar holdings, ask whether both are still necessary.

A repeatable overlap checklist

Save the current factsheet and holdings file for every ETF.
Record benchmark, domicile, replication and share class.
Compare top holdings, then the complete available lists.
Calculate effective portfolio weights for duplicated holdings.
Compare countries, sectors and concentration metrics.
Document whether each overlap is deliberate.
Repeat after an index or allocation change, not after every market headline.

Common mistakes

The first mistake is counting tickers instead of exposures. The second is treating trading currency as asset geography. The third is using stale holdings from different dates. The fourth is adding a thematic ETF whose largest positions already dominate the core fund.

Keep the analysis educational and proportional. A spreadsheet can clarify exposure, but it cannot choose a suitable allocation for an individual investor.

FAQ

What percentage of overlap is too high?

There is no universal threshold. The relevant question is whether the duplicated exposure is intentional, understood and compatible with the portfolio's role.

Can two global ETFs have low overlap?

Yes, if they follow materially different universes or methodologies. Verify the index rules and holdings rather than relying on the word “global”.

How often should holdings be compared?

Review after a fund or index methodology change, a portfolio allocation change, or a scheduled annual review. Daily comparison is rarely useful for a long-term process.