Premiums have risen 51% in five years. No new insurer has entered the highest-risk markets despite government intervention designed to attract them. The question the industry prefers not to ask is whether concentration itself is part of the problem.
There is a version of the Australian general insurance story that the industry tells confidently, and it goes like this: a concentrated market is not necessarily a harmful one. The four dominant carriers - IAG, Suncorp, QBE and Allianz - have invested heavily in technology, catastrophe modelling, and claims capability. Their scale enables the reinsurance arrangements that make Australian weather risk transferable. Without that scale, the argument runs, the market would be less resilient, not more competitive.
It is a coherent argument. It is also, increasingly, being tested by evidence that points in a different direction.
Consider what the competition regulator has found. The ACCC's fourth annual insurance monitoring report, released in July 2025, concluded that while the government's cyclone reinsurance pool had moderated premium rises in the highest-risk areas, "premiums remain very high for many consumers and are generally rising in most parts of the country and concerns around affordability remain." More telling was a separate finding buried in the same report: despite the pool being explicitly designed to encourage new insurers to enter or expand into northern Australian markets, no new insurers had entered those markets since the pool's introduction, and there had been "limited appetite from existing insurers to expand or increase their exposure overall."
The pool was meant to lower barriers. The barriers remained. That is not what a competitive market looks like.
The relationship between market concentration and consumer pricing is not simple, and it would be wrong to assert a direct causal link between Australia's oligopoly structure and the 51% cumulative rise in home insurance premiums over the past five years. Reinsurance cost increases, catastrophe losses, supply chain inflation, and claims cost pressures are all genuine contributors to that trajectory, and they would have driven premiums higher in any market structure.
But concentration affects pricing in ways that are distinct from those cost drivers - and the distinction matters.
In a genuinely competitive market, carriers compete on pricing precision. A carrier that prices a particular risk more accurately than its competitors will attract better risks and repel worse ones, generating underwriting profit that can be shared with customers through lower premiums. Over time, pricing competition drives the market toward actuarially fair premiums - or close to it.
In a concentrated market, the incentives are different. When four carriers hold 74% of the market and the largest two hold more than half, the competitive pressure to offer the sharpest price to any given customer is reduced. The market dynamic shifts from competing to attract customers toward managing a captive book.
One specific mechanism worth attention is price optimisation - the practice of pricing renewal customers not purely on risk but on their estimated price sensitivity and propensity to shop around. Research published by the Actuaries Institute in 2025 found that price optimisation effects are influenced by market competitiveness, with effects "becoming less pronounced in more competitive environments." In plain terms: the less competitive the market, the more scope carriers have to use behavioural pricing techniques that extract value from loyal customers rather than pricing purely for risk. Australia's concentrated personal lines market is an environment where that scope is relatively wide.
The ACCC has advocated for reforms to improve pricing transparency precisely because it is concerned that consumers lack the information to make genuinely informed choices. The multi-brand architecture of the dominant groups makes this worse: a consumer who compares quotes from NRMA, CGU, and a third IAG-underwritten product is receiving prices calibrated within a single underwriting entity's portfolio, not between genuinely independent competitors.
IB asked the regulator if it would like to see more competition in the insurance industry. An ACCC spokesperson didn’t answer the question but said “Australia’s open market economy depends on strong competition between businesses” and referred IB to ASIC, the corporate and financial services regulator.
Concentration's effects on innovation are harder to measure but potentially more significant in the long run.
When a market is genuinely contestable - when a new entrant with a better product or pricing model can win meaningful share - incumbents innovate defensively. They invest in technology, product design, and customer experience because the alternative is losing ground to someone who does. The British market, with its far more fragmented personal lines landscape and its comparison website-driven competition, drove motor insurance pricing to levels of granularity and digital efficiency that incumbents had to match or lose.
Australia's challenger brands - Youi, Hollard, and Auto & General - have driven some of this dynamic. Youi's behaviour-based pricing model forced the incumbents to respond. Budget Direct's relentless price competition in direct channels kept motor premiums from rising as fast as they might otherwise have done. The challenger brands have done real competitive work.
But they have done it from a 10% market share base accumulated over fifteen years. The incumbents had the luxury of responding at their own pace, and the dominant groups' scale in reinsurance, data, and distribution made it difficult for challengers to penetrate commercial lines, strata, or the more complex personal lines segments where margins are highest.
The cyclone pool finding is the clearest evidence of the innovation deficit. A government intervention specifically designed to lower the barriers to entry in northern Australian insurance markets - providing subsidised reinsurance, reducing the capital requirements for carrying cyclone risk - failed to attract a single new entrant. The regulatory fix worked technically but failed commercially, because the barriers to competing in those markets extend well beyond reinsurance costs. Brand recognition, distribution relationships, broker networks, and the capital requirements of operating an APRA-authorised insurer make the insurance market structurally inaccessible to genuinely new participants regardless of whether the reinsurance pool exists.
If government-backed risk transfer cannot move the needle on competition, then the concentration problem is deeper than any single policy intervention can address.
The industry's defenders make three substantial points, and they are worth engaging seriously rather than dismissing.
The first is resilience. Australian general insurance requires carriers to absorb catastrophe losses that in some years are extraordinarily large. The 2022 south-east Queensland and New South Wales floods generated AUD 5.87 billion in insured losses - the most expensive natural disaster in Australian history. Absorbing losses of that magnitude requires substantial capital, sophisticated reinsurance programmes, and the operational capacity to process tens of thousands of claims simultaneously. A fragmented market of smaller carriers might struggle to respond at that scale without threatening financial stability.
The second is that the alternative - a market fragmented across many small carriers - is not obviously better for consumers. The United States, with its deeply fragmented state-by-state market, has produced its own affordability crisis in high-risk states like Florida and California, where carriers have exited rather than compete on risk they cannot price. Fragmentation is not a guarantee of competitive outcomes.
The third is that the challenger brand growth over the past fifteen years demonstrates the market is contestable. If the dominant groups were using their market position to extract supra-competitive rents, the challengers' ability to grow from zero to 10% on a price-competitive model would have been more difficult. The challengers grew because the incumbents' pricing left room for it.
These are genuine points. The first and third, in particular, have real force.
When IB asked NIBA if it would like to see more big players in the market, the broker body acknowledged that industry consolidation is a force reshaping global insurance but said Australian families and businesses still have access to genuine choice, expert guidance and the right coverage for their needs because of brokers.
NIBA’s response said underinsurance and insurance unaffordability “is not about industry consolidation. It is about risk.”
The statement said the best response to that is “long-term, indexed investment, at both community and household level, in disaster mitigation.”
Brokers approached by IB also take a nuanced view, including Sydney-based Austin Rosier.
“In the personal lines sector, it would be easy to simply ask more major players to step in and deploy capacity, or underwrite more freely,” said Rosier, Omnisure’s principal risk adviser. “However, we recognise that it isn’t that easy, and that there are very real commercial considerations towards doing so; an insurer cannot simply enter the market and continue to suffer losses indefinitely.”
Neil Luddington, account manager for Roberts Insurance Providers in Tasmania, agreed that competition among insurers is important and said part of a broker’s job is to encourage it. But from the perspective of his clients, Luddington said underwriting agencies, rather than the big four insurers, are providing quality offerings and competitive pricing.
“I am embracing the current proliferation of specialist underwriting agencies in Australia which combine the financial strength of their underlying underwriter with unmatched expertise in their narrow area of risk,” he said.
But, particularly beyond the market served by brokers, there are places where the concentration-is-fine argument strains against the evidence.
The first is the ACCC's repeated findings on affordability and the persistence of high premiums despite the cyclone pool. ACCC Chair Gina Cass-Gottlieb has been direct in calling for market reforms to improve competition and transparency in insurance, particularly in northern Australia. A regulator with responsibility for monitoring the market and no agenda other than consumer welfare has concluded that the market is not working well for consumers in high-risk areas. That conclusion should carry significant weight.
The second is the reasoning behind the ACCC's December 2025 decision to block IAG's acquisition of RAC Insurance. The regulator found that RAC Insurance was a "strong and profitable competitor" that would remain viable without being acquired, and that its absorption would substantially reduce competitive pressure in Western Australia because the "historical difficulties rivals have had in growing market share in Western Australia" meant that national competitors could not fill the gap. In other words: the geographic concentration of competition in individual state markets means that even a nationally fragmented market can be locally monopolistic. The ACCC's block was not just about Western Australia - it was a finding about the structural limits of what challenger brands and national incumbents can do to discipline pricing in geographically isolated markets.
The third is the ASIC enforcement record. ASIC's 2026 priorities name claims handling failures and misleading pricing practices as the two top insurance enforcement actions. Federal Court proceedings against RACQ Insurance for allegedly false premium comparisons in renewal notices - involving, according to ASIC's claim, over 570,000 notices - suggest that the market's dominant players have not always competed on transparent terms. A more competitive market, in which customers could more readily switch and in which new entrants were actively targeting the disgruntled books of established carriers, would create stronger commercial incentives for transparent pricing.
There is a final dimension to the concentration question that receives almost no attention: the systemic risk of a market where two carriers together hold more than half the premium base.
APRA's Insurance Climate Vulnerability Assessment, published in March 2026, projects that home insurance becomes unaffordable for roughly one in four Australian homes by 2050 under plausible climate stress scenarios. The policy responses being contemplated - government-backed risk pools, parametric products, potential subsidies - all involve the state stepping in where private markets pull back.
But the design of those interventions will be shaped, in part, by what the private market is willing to do. A concentrated market with two dominant carriers has enormous influence over how those negotiations play out. If IAG and Suncorp together decide that a particular category of risk is not commercially viable at any price that households can afford, there is no competitive market mechanism to challenge that judgment. The ARPC cyclone pool was established precisely because the private market had effectively decided that northern Australian cyclone risk was uninsurable at affordable premiums. The pool addressed the symptom. The underlying dynamic - a market too concentrated to be self-correcting in the face of extreme risk - has not changed.
Is Australia's concentrated general insurance market actively harming the people it is meant to serve? The honest answer is: in some markets, for some risks, for some consumers - yes.
In mainstream urban personal lines, the evidence for significant consumer harm from concentration alone is limited. The challenger brands have kept competitive pressure on motor and home pricing in major cities. The industry has earned substantial profits in the recent hard market, but those profits followed years of underwriting losses. The cycle runs as it runs elsewhere.
But in northern Australia, in regional markets with limited competitive alternatives, in commercial lines segments dominated by two underwriters, and in the slow-moving response to the cyclone market's accessibility problem - in all of these, the concentrated structure of the market has produced outcomes that a more competitive market would not have produced. Prices are higher, product innovation is slower, and new entrants are absent not because they lack appetite but because the structural barriers in an oligopolistic market are genuinely difficult to overcome.
The question for regulators, policymakers and the industry itself is whether the resilience benefits of concentration are worth those costs. The ACCC's growing willingness to challenge further consolidation - its Northern Australia Insurance Inquiry, its annual monitoring reports, its block on the RAC Insurance acquisition - suggests that the regulator has concluded the trade-off is not always worth it. That conclusion deserves to be taken seriously.
