Oligopoly in Australia: What It Means for Your Money in 2026

An oligopoly exists when a market is dominated by a small number of powerful firms. Unlike a monopoly (where one player rules), an oligopoly features a handful of giants who often move in lockstep, making it tough for new competitors to break through. In Australia, this is more the rule than the exception:

• Supermarkets: Coles and Woolworths control over 65% of the grocery sector, with Aldi trailing distantly.

• Banking: The ‘Big Four’—Commonwealth Bank, Westpac, NAB, and ANZ—dominate lending, savings, and everyday banking.

• Telecommunications: Telstra, Optus, and TPG/Vodafone together cover over 85% of the mobile and internet market.

• Energy Retail: AGL, Origin, and EnergyAustralia supply most households in the eastern states.

These oligopolies have been reinforced by decades of mergers, regulatory hurdles, and the sheer cost of entry into these sectors. For consumers, the result is often less choice, stickier prices, and more similarity between products than meets the eye.

With cost-of-living pressures peaking, 2026 has become a pivotal year for competition policy in Australia. The Albanese government’s Competition Review, due for release mid-year, is expected to recommend tougher rules for mergers and greater powers for the ACCC to investigate anti-competitive conduct. Meanwhile, the supermarkets inquiry—sparked by allegations of price gouging—has put oligopoly practices under the microscope.

Key policy developments to watch:

• Merger Law Overhaul: The government is considering a ‘clearance’ model that would force big companies to prove their deals won’t harm competition, shifting the burden of proof.

• Supermarket Code of Conduct: New mandatory rules are likely to be introduced, targeting pricing transparency and supplier treatment.

• Open Banking Expansion: More data-sharing requirements could make it easier for consumers to switch banks, challenging the Big Four’s hold.

These shifts are designed to crack open closed markets, but change won’t come overnight. The lesson? Australians need to stay sharp and shop around, but also push for policy reforms that make real competition possible.

The effects of oligopoly are felt in subtle—and not-so-subtle—ways across Australian households:

• Grocery Prices: The ACCC’s 2024 interim report found that Coles and Woolworths enjoyed profit margins higher than global peers, with limited price competition on everyday staples. Expect more scrutiny on whether ‘specials’ are truly bargains.

• Banking Fees & Mortgage Rates: Despite RBA rate moves, the Big Four have tended to move together on mortgage rates. Smaller lenders offer sharper deals, but market share remains stubbornly concentrated.

• Mobile & Internet Plans: While smaller brands exist, most are ‘virtual’ operators leasing network access from the big three. True competition on price and speed is often limited.

• Energy Bills: Although deregulation was meant to spur choice, many consumers still stick with the big players, who are able to set similar rates across the market.

The upshot? Oligopoly often means less pressure to innovate or drop prices, and consumers need to be proactive to get the best deal. Watch for new government tools and comparison websites launching in 2026, designed to help you break out of the ‘big four’ rut in key sectors.

With the policy spotlight on market concentration, 2026 could see the first real cracks in Australia’s oligopolies in years. But real change depends on both tougher regulation and more informed, active consumers. Whether it’s switching banks, trying a smaller energy retailer, or demanding more transparency from supermarkets, Australians have more power than they think—especially when backed by smart policy.