Methodology

How ETFLens Calculates ETF Overlap

The methodology, data sources and limitations behind the overlap percentage shown in every comparison.

The data source

ETFLens calculates overlap from each fund's full published holdings listwhere the issuer publishes one, including Vanguard, BetaShares, iShares, VanEck, SPDR and Global X funds. Where an issuer publishes only its largest positions, the fund's listed top holdings are used instead and the result is labelled as an estimate. The figures are taken directly from each issuer's published disclosures (portfolio holdings files, fact sheets, Product Disclosure Statement (PDS) documents and ASX announcements), not scraped from third-party aggregators, and the holdings, tickers and weights are refreshed at least quarterly. General information only, not financial advice.

The calculation

For each fund, ETFLens reads its listed top holdings and their published weights. It then finds the holdings that appear in both funds. For every shared holding, it takes the smallerof the two weights (the most either fund can genuinely have in common for that company) and adds those up. That shared total is then expressed as a share of the smaller fund's listed top-holdings coverage and shown as a percentage.

The result is rounded down to a whole number. Where a fund publishes its top holdings without weights, ETFLens assumes equal weights across that fund's listed holdings so a comparison is still possible. These cases are flagged as an estimate. Where two funds share no listed top holdings, the result is shown as “not reliably estimable” rather than as 0%.

What the number means

An overlap of 94% means that, of money split equally between the two funds' listed top holdings, approximately $940 of every $1,000 is in the same underlying companies. The remaining portion is held in companies unique to one fund or the other. The percentage describes shared holdings, not shared performance, and is general information only, not financial advice.

Limitations

• Published holdings, not always full constituents. Where a fund publishes only its largest positions, the estimate uses those rather than the full constituent list, so overlap deeper in the portfolio is not captured. Each result states the holdings basis it was calculated on.
• Fund-of-funds structures. All-in-one diversified funds such as VDHG and DHHF hold other funds rather than individual shares, so their listed top holdings make overlap with single-exposure ETFs unreliable.
• Point-in-time data. Holdings are refreshed at least quarterly (more often for providers with automated feeds), so changes a fund makes between refreshes are not reflected until the next refresh.
• Cross-market pairs. Funds covering different markets (for example VAS and NDQ) often share no listed top holdings and will show as “not reliably estimable”.

Data sources and update frequency

• Fund manager portfolio holdings files, fact sheets and Product Disclosure Statement (PDS) documents
• ASX announcements and issuer product pages
• Refreshed at least quarterly (more often for providers with automated feeds), with corrections made when errors are found

For the current data status and the quarter each figure was last reviewed, see the ETFLens data page.