What is an ETF twin?
An ETF's “twin” is another fund whose holdings overlap so heavily that the two give very similar market exposure. Most Australian broad-market ETFs, for example, are dominated by the same handful of large companies - CBA, BHP, CSL and the major banks appear near the top of almost all of them - so their holdings overlap a great deal. A high overlap means holding both funds adds little diversification, because the two largely duplicate each other's holdings.
A “twin” describes shared holdings, not a claim that two funds are the same. Even funds that overlap heavily can differ in important ways, which is why this tool reports the overlap percentage and the shared holdings rather than labelling any fund a replacement for another.
How to read the overlap percentage
The percentage estimates how much of two funds' holdings are shared, weighted by how much each fund allocates to them. As a rough guide: approximately 90% or more means the funds hold almost all of their listed holdings in common; roughly 70% to 90% is very high; 40% to 70% is moderate; and below approximately 30% is low. The higher the figure, the more alike the two funds behave, and the less a second fund adds on top of the first.
Why look for an ETF's twin?
Knowing a fund's closest twins is useful for a few factual reasons:
- Spot duplicated exposure. If two funds you hold are twins, you may be paying two sets of management fees for largely the same companies. The Overlap Checker shows the duplication for any pair.
- See lower-fee funds with similar exposure. Among twins, management fees can differ. The tool shows each twin's MER and the difference versus your fund, stated factually rather than as a suggestion that one is better.
- Understand your real diversification. A portfolio of five ETFs that are mostly twins of one another is less diversified than the number of funds suggests.
Twins are not perfect substitutes
High holdings overlap describes what two funds hold, not everything about them. Two twins can still differ on management fee, the index they track and how it is weighted, distribution frequency and franking, domicile and tax treatment, fund size and liquidity, and how closely each tracks its index. A lower fee can also carry a capital gains tax cost if switching means selling units you already hold. Before treating one fund as a substitute for another, compare them in full and read each fund's Product Disclosure Statement.
How this tool finds twins
Enter a ticker and the tool compares that fund's published top holdings, weighted by allocation, against every other ASX ETF that ETFLens tracks, then ranks them by overlap and lists the holdings they share. Figures are estimated from listed top holdings rather than full constituent lists, are shown as “approximately”, and are refreshed at least quarterly. This is general information only, not financial advice.
Frequently asked questions
What does it mean if two ETFs are twins?
Here, twin means two ETFs whose published holdings overlap heavily, so they give very similar market exposure. It describes how much the funds hold in common - not that they are the same fund. Twins can still differ on management fee, index, distributions and tax.
Are VAS and A200 twins?
They overlap heavily - approximately 94% by holdings - because both track the largest companies listed on the ASX. They are not interchangeable: they follow different indices (VAS the S&P/ASX 300, A200 the Solactive Australia 200) and charge different management fees. Compare them in full before treating one as a substitute for the other.
Does high overlap mean two ETFs are interchangeable?
No. High holdings overlap means the funds hold many of the same companies, but they can still differ on management fee, index methodology, distribution frequency and franking, domicile and tax treatment, fund size and liquidity, and how closely each tracks its index. Overlap describes holdings, not every characteristic.
Is it a problem to hold two overlapping ETFs?
It is not inherently a problem, but it is worth being aware of: holding two heavily overlapping funds means paying two sets of management fees on largely the same companies, and it adds little diversification. Whether that matters depends on your own goals and circumstances.
How is ETF overlap calculated?
The tool compares each fund's published top holdings, weighted by allocation, and reports the proportion the two funds share. Figures are estimated from listed top holdings rather than full constituent lists, are shown as approximately, and are refreshed at least quarterly. See the dedicated Overlap Checker for a single pair in more detail.
Which ASX ETFs have the most twins?
Broad-market index ETFs tend to have the most twins, because many funds track similar baskets of large Australian or global companies and therefore share the same mega-cap holdings. Narrow, thematic or actively managed funds usually have fewer close twins.
Does ETFLens tell me which ETF to switch to?
No. This tool provides general information only, not financial advice or a recommendation to buy, sell or switch any fund. If you are weighing up a change, model the capital gains tax break-even with the Switch Calculator, read each fund's Product Disclosure Statement, and consider advice from a registered tax agent or licensed financial adviser.