Westpac Sheds Most Big Four Mortgage Share Since 2019

New APRA data shows Westpac has lost 3.2 percentage points of Australia's home loan market since 2019, while CBA has quietly grown its share.

The Big Four Mortgage Market Has Been Reshuffled

New data from the Australian Prudential Regulation Authority (APRA) confirms that Australia's home loan market looks meaningfully different from where it stood seven years ago. The March 2026 edition of APRA's Monthly Authorised Deposit-taking Institution Statistics shows that not all of Australia's major banks have kept pace as the mortgage market expanded by $752 billion since March 2019.

Westpac's position stands out. Australian Broker [reports](https://www.brokernews.com.au/news/breaking-news/westpac-haemorrhages-market-share-as-cba-tightens-its-grip-on-australian-mortgages-289295.aspx) that the bank now holds 20.7% of Australia's $2.46 trillion mortgage market, down from 23.9% in March 2019 — a fall of 3.2 percentage points that is more than double the decline recorded by any other major bank. In dollar terms, Westpac's book has grown from $408 billion to $509 billion over those seven years, a 24.7% increase. But the overall market grew 45.5% in the same period, meaning Westpac's growth badly trailed the pace set around it.

The contrast with Commonwealth Bank of Australia (CBA) is sharp. CBA grew its book from $429 billion in March 2019 to $624 billion in March 2026 — an increase of $195 billion representing roughly 26 cents of every new dollar lent in Australia over those seven years. CBA's share has edged up to 25.4%, from 25.1%, making it the only major bank to have grown its share over this period.

NAB has slipped 1.2 percentage points to 14.1% and ANZ has fallen 1.4 percentage points to 13.2%. Both declines are real but modest compared with Westpac's. Beyond the big four, Macquarie alone has captured nearly 5 percentage points of market share since 2019, a structural shift that reflects genuine price and service competition benefiting borrowers who are willing to look beyond the traditional majors.

How the Ground Was Lost — and What It Means for Brokers

Westpac's share erosion has been gradual rather than sudden. From 23.9% in 2019, the bank fell to 21.7% by March 2022, then to 21.0% by March 2025, and 20.7% by March 2026. The steepest period was 2019 to 2022, when 2.2 percentage points were shed in three years. This coincided with Westpac's response to the Royal Commission into Banking, which included a tightening of credit policy and a temporary withdrawal from some broker segments — windows that CBA and later Macquarie used to aggressively expand their broker-originated pipelines.

Since 2022 the decline has continued at a more moderate pace of roughly 0.3 percentage points per year. Westpac has grown its absolute book in each of those years, but not fast enough to match a market expanding at 6–8% annually. The bank's own first-quarter FY26 results confirmed that mortgages originated through proprietary channels fell to 44.4% of the total, down from 47.3% the prior year, as Westpac leans more heavily on its broker network to keep volumes ticking. Full-year FY25 results showed home loan growth of just 5%, trailing the broader market, with net interest margin under pressure from what the bank itself described as "persistent competition."

For brokers and the clients they serve, a lender under share pressure behaves differently from one that is comfortably winning. A bank seeking to rebuild origination volumes may offer more competitive pricing or greater policy flexibility on specific scenarios. Westpac has invested significantly in its broker proposition under its Westpac and St.George brands in recent years, and absolute volumes have grown; the relative underperformance is a market-share story, not necessarily a product quality story.

CBA's growing share reflects a lender winning across both broker and direct channels simultaneously. This can create rate differentials between how the bank prices for direct customers versus broker-referred clients — a gap worth monitoring at your next review.

What This Means If You're Shopping for a Home Loan

For borrowers, the key takeaway from the APRA data is that lender competition is real and consequential. With the cash rate now at 4.35% following the RBA's third consecutive hike of 2026, the gap between lenders on pricing and credit policy has rarely mattered more.

NAB and ANZ sit in a middle position — both losing share moderately, and both with broker networks historically well regarded for turnaround times and BDM accessibility. Neither faces the same competitive pressure as Westpac.

Rates across the market vary by more than many borrowers realise. A difference of even half a percentage point on a $600,000 loan translates to thousands of dollars over the life of the loan. Use our [refinance savings calculator](/calculators/refinance-savings) to see what a rate improvement could mean for your monthly repayments. For a live view of current rates across major and non-major lenders, [compare Australia's cheapest home loans](/home-loans/cheapest). If you are actively considering switching lenders, the [refinance hub](/home-loans/refinance) has a step-by-step guide on when refinancing makes sense and what costs to factor in.

The $2.46 trillion Australian mortgage market is more competitive than at any point in recent memory. The APRA data confirms that challenger lenders have taken share from the big four in a sustained and meaningful way. Whether your current lender is still working for you is a question worth asking.