Two kinds of overlap
The key distinction — and the one most tools skip — is that exact holding overlap and economic exposure overlap are not the same thing.
Constituent overlap
The same companies appear in more than one fund. Most broad Australian index funds are built from the same large caps, so two "different" ETFs can share a big chunk of their actual holdings — the same banks and miners, in slightly different weights.
Economic overlap
Different holdings that depend on the same underlying forces. A resources ETF and an emerging-markets ETF may share almost no tickers, yet both lean heavily on Chinese demand and commodity prices — so they can move together when it matters most.
Three ways your ETFs can overlap
Put those two ideas together and any pair of funds you hold usually falls into one of three situations:
- Substantial constituent overlap — they hold many of the same companies, so you own more of the same names than you realised.
- Little apparent ticker overlap, but meaningful shared economic exposure — the holdings look different, yet they respond to the same economic drivers.
- Both — overlapping holdings and overlapping economic exposure, which is where a multi-ETF portfolio can quietly become one concentrated bet.
The one most investors miss is the middle case — because it's invisible on a holdings list. Two funds with barely any shared tickers can still be making the same economic bet.
What PortLens estimates — and what it doesn't
PortLens focuses on the second kind of overlap: shared economic exposure. Using look-through factor estimates, it works out whether your funds and holdings depend on the same underlying forces — banks, resources, interest rates, Chinese demand, the Australian dollar — and where those bets stack up.
It does not compare every constituent of each ETF or calculate an exact "these two funds share X% of the same companies" figure. That requires complete, current constituent-level holdings data, which PortLens doesn't claim to hold. So the question PortLens answers is "are my ETFs making overlapping economic bets?" — not "exactly which companies do they share?" Both questions are useful; PortLens is honest about which one it's built to answer.
A concrete example
Illustrative example — not a real portfolio
Imagine you hold a broad ASX 200 fund, an Australian "high dividend" ETF, and a listed investment company you've owned for years. On paper that's three different products across three different strategies — it feels well spread.
But the broad fund is already about a quarter big banks; the high-dividend ETF deliberately leans into the same banks and other high-payout names; and the LIC has long favoured large Australian financials. The tickers aren't identical, but the economic exposure is heavily overlapping — three products, largely one bet on Australian banks and interest rates.
Nothing here is wrong to own. The point is simply to see it clearly, rather than assume three funds means three different exposures.
What PortLens actually analyses
- The shared economic exposure across your funds and holdings — where different products depend on the same underlying drivers.
- Your major economic bets — how many distinct forces (banks, iron ore, China, rates, currency) actually move your portfolio once your ETFs are looked through.
- Your concentration and effective number of holdings — so a multi-ETF portfolio that's really one bet shows up as one.
- Where holdings you think of as separate turn out to overlap economically.
It describes how your ETFs overlap economically — it doesn't grade them, and it never tells you what to buy or sell. The goal is to understand what you actually own.
Methodology & limitations
- • For funds and ETFs, PortLens uses look-through estimates of economic exposure — not a full constituent-by-constituent holdings list. These are approximations and are labelled as estimates.
- • PortLens does not calculate exact shared-constituent percentages between two ETFs; it estimates overlapping economic exposure, which is a different (and complementary) question.
- • Prices are end-of-day (daily) market data, not real-time.
- • There is no single "too much overlap" threshold — how much overlap is appropriate depends on your goals, timeframe and circumstances.
- • PortLens provides general information and portfolio analysis only. It is not personal financial advice or a recommendation to buy or sell.
Frequently asked questions
How much ETF overlap is too much?
There's no universal threshold — how much overlap is appropriate depends on your goals, timeframe and what you intended each fund to do. The problem isn't overlap itself; it's unintended overlap, where funds you thought were spreading your risk are quietly making the same economic bet. The useful step is to see how much your funds actually share — in economic exposure, not just tickers — and then decide whether that matches what you meant to hold.
Is there an ETF overlap tool for Australian investors?
PortLens offers a free ASX-focused snapshot that estimates whether your ETFs and holdings are making overlapping economic bets — looking through your funds to shared drivers like Australian banks, resources, interest rates and the Australian dollar. It estimates shared economic exposure rather than an exact percentage of shared constituents, and requires no signup or broker login.
Do two ETFs with different tickers give me different exposures?
Not necessarily. Two funds can hold overlapping companies, or hold different companies that still depend on the same economic forces — Australian banks, resources, interest rates or the Australian dollar. Different tickers don't guarantee different exposures, which is why holding several ETFs can feel more diversified than it really is.
Can PortLens tell me the exact percentage of holdings two ETFs share?
No. PortLens estimates the shared economic exposure between your holdings using look-through factor estimates. It does not compare every constituent of each ETF or calculate an exact percentage of shared holdings — that requires complete, current constituent-level data that PortLens doesn't claim to hold. It answers whether your ETFs are making overlapping economic bets, not exactly which companies they share.
How do I check whether my ETFs overlap?
PortLens offers a free ASX portfolio snapshot: paste your holdings and it estimates whether your funds are making overlapping economic bets and where their exposures stack up — with no signup required.
See what your ETFs are really exposed to
Paste your ASX holdings — funds included — and get a free snapshot of the economic bets your ETFs are really making, and where they overlap. No signup, no broker login.
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