Woolworths holds an estimated 38 per cent of national supermarket grocery sales and Coles 29 per cent — 67 per cent between them. After a year-long inquiry, the ACCC's central finding about that was not that the two chains conspire. It was quieter and harder to fix: they have "limited incentive to compete vigorously with each other on price".
That is the duopoly problem in one line. Prices do not stay high because someone decided to raise them. They stay high because nothing in the market structure obliges anyone to bring them down.
What is worth knowing — and what almost no coverage of this says — is which remedy the regulator picked. It did not recommend capping prices. It recommended making them comparable, on the theory that shoppers who can actually tell who is cheaper are the pressure that has been missing. More than a year on, that remedy is still a consultation paper.
What the ACCC actually found
The inquiry ran for a year, took more than 20,000 consumer survey responses, and produced a final report dated February 2025, which the ACCC published on 21 March 2025. Both dates get quoted as "the report", which is why coverage of it never quite agrees. Four findings matter here.
The market is concentrated and the two leaders face no rival of comparable scale. Woolworths at 38 per cent and Coles at 29 per cent sit well clear of everyone else.
They do not undercut each other. The ACCC said it had "not observed Coles and Woolworths seeking to substantially discount prices below each other in aggregate", and that both had maintained or increased their product margins despite rising costs.
They are highly profitable by international standards. The ACCC found ALDI, Coles and Woolworths appear to be among the most profitable supermarket businesses globally.
It did not find price gouging. This is the part most commentary skips. The final report did not accuse the supermarkets of price gouging. A separate law banning excessive pricing did start on 1 July 2026, and we went through what it does and does not do separately.
So the honest answer to "are we being ripped off" is: not in the way the word implies. The finding is structural, not criminal, which is precisely why it has proven so difficult to legislate away.
Two chains, one price
The clearest way to see "limited incentive to compete" is not in a profit statement. It is in what happens when you price the same product at both chains on the same day.
10,988 identical products priced at both Coles and Woolworths.
- Same price at both
- 46.9%
- Cheaper at Woolworths
- 28.2%
- Cheaper at Coles
- 24.9%
Where the two differ, the middle gap is $2.00 — about 28.6% of the dearer price. Across the whole set, taking whichever chain is cheaper on each product comes to 9.7% less than buying all of them at either one.
And most of that difference is a promotion rather than a different shelf price: 85.1% of the products where the two chains differ have at least one side on special.
Grovena’s own data, updated with each price collection — figures as at 27 September 2026. Current prices including anything on special that day, so the split moves week to week. The 9.7% is what the gap adds up to across every product in this set, not a saving on a real shop: collecting it would mean buying all of them and shopping both chains. Online prices, so in-store tickets and state-based variations sit outside it.
That panel is generated from our own catalogue and moves with each collection, which is why the figures live in it rather than in this sentence. Three things in it are worth reading together, because the first one alone would be a cherry-pick.
They match on close to half. Same product, same day, same price to the cent — at the two chains that are supposed to be each other's main competition.
Where they differ, it is usually a promotion. The middle gap is not a rounding error — but on the products where the two chains part company, the large majority have at least one side running a special that week. That is the more revealing number, because it says the divergence is not two chains setting different shelf prices. It is two chains holding the same shelf price and taking turns discounting off it.
But the differences cancel. Coles comes out cheaper on roughly as many products as Woolworths does, the two shares sitting within a couple of points of each other. Neither is the cheaper shop. Each is cheaper on a different slice of the same catalogue.
Those last two points are the ACCC's wording made concrete. It never said the two chains do not differ on price. It said it had "not observed Coles and Woolworths seeking to substantially discount prices below each other in aggregate" — and a near-even split of wins across thousands of products, driven mostly by whose promotion is running, is what "in aggregate" looks like from the shelf.
That distinction matters more than it sounds. A permanent price cut is a decision to earn less on a product indefinitely, and it invites the other chain to follow. A special is temporary, loudly advertised, and expires by itself. A market where the visible price competition is almost entirely promotional is one where the base prices have stopped moving against each other — which is close to a description of what the ACCC found. The prices move constantly. The ranking does not move at all.
Neither chain has to phone the other for this to happen. Both watch each other's prices, both know the other is watching, and in a market with two large players and no third of comparable size, matching is simply the rational move. Undercutting starts a fight that costs both of them margin and wins neither a lasting customer.
This is also why "which supermarket is cheapest" turns out to be the wrong question to organise your shopping around. On the products where the big two are level, the chain you choose is not the decision that moves your bill.
Why more competition has not fixed it
The standard answer to a concentrated market is a new entrant. Australia has one, and it illustrates the problem rather than solving it.
ALDI acts as a genuine price constraint — but it does not compete head-to-head on all products, because it stocks a narrow range of mostly own-label goods. If you buy particular brands, ALDI often cannot be part of the comparison at all.
And scale takes a very long time. The ACCC noted it took ALDI more than 20 years to reach nine per cent of the market, against "significant barriers for new or smaller supermarkets to enter and expand at a large scale". One of those barriers is not the supermarkets at all: the availability of suitable retail sites "is limited by planning and zoning laws, which restrict overall supply and can deter entry or expansion".
A fourth chain is not arriving this decade. Whatever changes the balance in the meantime has to work with the three we have.
The lever the regulator chose: transparency
Here is the interesting turn. Faced with a structural problem, the ACCC's consumer-facing recommendations were mostly about information, not price.
Its reasoning is worth stating plainly, because it is the reasoning behind every price comparison tool in the country. In a competitive market, the thing that forces prices down is shoppers moving. Shoppers can only move if they can tell where the better price is. Make comparison possible, and you restore the incentive that concentration removed. As Deputy Chair Mick Keogh put it about disclosing package size changes, transparency means consumers "would be better able to 'vote with their feet' and switch to cheaper alternatives if that is their preference".
The recommendations that follow from that are unusually concrete. The ACCC recommended that ALDI, Coles and Woolworths be required to publish their prices on their websites, and that Coles and Woolworths make application programming interfaces available that provide dynamic price information to third parties such as online price comparison tools.
Read that again, because it is a striking thing for a competition regulator to say. Its recommended fix for the duopoly is that the duopoly hand its price data to comparison services — the tools that exist to help you shop somewhere else.
Alongside it sat minimum information requirements for promotions, mandatory notice when a package shrinks, and periodic loyalty program summaries. All the same shape: not "charge less", but "make it possible to tell".
There is evidence that shoppers would use it. In the ACCC's own survey, almost 50 per cent of respondents said they "always" or "most times" compare prices between stores before shopping — against 17 per cent at the 2008 Grocery Inquiry. The same survey found the majority of low-income respondents spend more than 20 per cent of their net income on groceries, and that many consumers reported losing trust in supermarkets' sale price claims.
Australians are already trying to compare. What they have been missing is data that makes it possible.
Where that has actually got to
Not law. Not yet.
Treasury opened a consultation on price and loyalty transparency on 20 January 2026, with submissions closing on 17 February 2026. It proposed requiring all supermarkets to publish prices in-store, and large supermarkets to publish prices online, display minimum information about promotions, and provide six-monthly loyalty program summaries.
One detail in it deserves more attention than it got. The ACCC recommended the majors provide APIs. Treasury's proposal asks large supermarkets to "ensure web-scraping technologies can be used by third parties like online comparison websites and apps".
Those are not the same requirement. An API is a supported, structured feed the retailer maintains and stands behind. Not blocking scrapers is an obligation to stop doing something — it leaves comparison services collecting prices off public web pages, which is exactly the fragile arrangement the ACCC's recommendation was meant to replace. It is a meaningful step, and it is a softer one.
As at today, the enforceable change that has landed is the excessive pricing prohibition that started on 1 July 2026. The transparency measures — the ones aimed squarely at the incentive problem — are still upstream of legislation.
Meanwhile prices have not stopped rising. Food and non-alcoholic beverages rose 3.3 per cent in the year to June 2026, with the CPI overall up 3.8 per cent. That category is broader than a supermarket trolley — it includes meals out and takeaway — but the direction is the point. Nothing announced so far has produced falling grocery prices, and no one credible has promised it would.
What you can do before the rules catch up
The uncomfortable implication of everything above is that the comparison work is currently yours to do. That is not a satisfying conclusion, but it is the accurate one, and it does narrow down to a few moves that actually matter.
Compare per product, not per chain. When the two majors sit level on close to half of identical items and split the rest almost evenly, picking a "cheapest supermarket" and shopping there decides very little. The differences are real and worth catching — they are just item by item rather than chain by chain. Compare the item, not the chain — each card shows the retailers we hold a matched price for, and a missing chain means we have not matched that product there, not that it is unstocked.
Compare unit prices, not shelf prices. Price per kilo or per litre is the only figure that survives a pack size change, and shrinkflation is common enough that the ACCC recommended mandatory notice of it. Unit prices sit on the product cards, and seeing them does not need an account.
Treat a "was" price as unproven. A ticket comparing today's price to a number you cannot check is a claim, not a saving — the ACCC's survey found consumers had already worked this out. We went through when a half-price ticket is a real discount separately.
When the chains are level, the question becomes when
This is the tactic worth learning from the parity data above. If the two majors hold the same shelf price on a staple, and the gaps that do appear are mostly one of them running a special, then no amount of switching chains helps you. The money is in the weeks when one of them discounts it.
Months of a single product's price tell you things a shelf label cannot: how often it goes on special, how deep the discount usually goes, and whether the current "was" price was ever really charged. A staple that drops every six weeks is a completely different buying decision from one that drops twice a year — the first you wait for, the second you buy when you see it.
The same logic scales badly by hand and well by automation. Watching the twenty or so staples you rebuy every fortnight is not realistic manually; set against those items, a drop finds you instead of you checking.
Both of those are Grovena Pro features — full price history charts and weekly price-drop alert emails — at $5.99 a month, or $49.99 a year. And they are worth being specific about what they are not for: they earn their keep on the products you buy repeatedly. For a one-off purchase, the current price on a free product card already answers the question, and history tells you nothing you will use.
The short version
- Woolworths and Coles account for about 67 per cent of national supermarket sales, and the ACCC found they have limited incentive to compete vigorously with each other on price.
- In our own catalogue they charge exactly the same on close to half of identical products, and split the rest almost evenly — so neither is the cheaper shop.
- Where they do differ, the large majority of those gaps have one side on special: the two are holding the same shelf price and taking turns discounting, not undercutting each other.
- The regulator did not find price gouging. The problem it identified is structural: nothing forces prices down.
- ALDI constrains prices but does not compete on every product, and took more than 20 years to reach nine per cent. Planning and zoning laws are part of why a fourth chain has not arrived.
- The ACCC's recommended fix was transparency — including that Coles and Woolworths hand price data to comparison tools via APIs.
- That is still a consultation, and Treasury's version asks only that the chains not block web scraping.
- Until it lands, comparison is the shopper's job. Compare per product, use unit prices, and on staples, watch for when rather than where.
Common questions
Is the Australian supermarket sector a duopoly?
Effectively, yes at the top. The ACCC estimated Woolworths at 38 per cent and Coles at 29 per cent of national supermarket grocery sales — 67 per cent between them — with no rival of comparable scope and scale. ALDI, Metcash-supplied independents and others share the rest.
Did the ACCC find Coles and Woolworths were price gouging?
No. Its February 2025 final report did not accuse them of price gouging. It found something different: that the two have limited incentive to compete vigorously on price, and that their margins rose over five years. A separate law banning excessive pricing by the very largest supermarkets took effect on 1 July 2026.
Do Coles and Woolworths charge the same prices?
On close to half of identical products, yes — the same item, the same day, the same price to the cent. Both watch each other's prices closely, and in a market with two dominant players, matching is the rational move rather than evidence of an agreement. Where they do differ, the large majority of those gaps have at least one chain running a special, so the difference is usually a promotion rather than a cheaper shelf price — and neither chain is systematically cheaper, the wins splitting almost evenly between them. That is why choosing a chain is not what decides your bill. The live panel above measures all of it, and moves week to week.
Why doesn't ALDI force Coles and Woolworths to drop prices?
It constrains them, but only partly. ALDI stocks a narrower, mostly own-label range and does not compete head-to-head on every product, so for branded goods it often is not in the comparison at all. It also took more than 20 years to reach nine per cent of the market — scale in Australian grocery is slow to build, partly because planning and zoning laws limit suitable sites.
Will the new transparency rules make groceries cheaper?
Nobody can promise that, and the government has not. The theory is indirect: easier comparison makes switching easier, and switching is what creates pressure to compete. Whether it shows up at the shelf depends on how strong the final rules are — and the version out for consultation was softer than what the ACCC recommended.
Are grocery prices still rising in Australia?
Yes, more slowly than at the peak. Food and non-alcoholic beverages rose 3.3 per cent in the year to June 2026, against 3.8 per cent for the CPI overall. That category includes meals out and takeaway as well as supermarket groceries.
The duopoly is not going to be competed away this decade, and the rules meant to counter it are still being written. In the meantime, the only pressure available is shoppers who can see the difference. See which chain is cheaper on your items before your next shop.