Westpac has shed more ground in the Australian home loan market than any of its major bank peers over the past seven years, with new APRA data showing the bank's share of national mortgage lending falling 3.2 percentage points since March 2019, a loss that dwarfs the declines recorded by National Australia Bank (NAB) and ANZ, and stands in stark contrast to Commonwealth Bank of Australia (CBA), which has actually grown its share.
The March 2026 data from APRA's Monthly Authorised Deposit-taking Institution Statistics shows Westpac now holds 20.7% of Australia's $2.46 trillion mortgage market, down from 23.9% in March 2019. In a market that has grown by $752 billion over that period, Westpac's book has expanded by just $101 billion, a 24.7%increase that badly trails the 45.5% growth recorded by CBA over the same stretch.
The result is a competitive landscape that looks meaningfully different to the one that existed before the pandemic. CBA, always the market leader, has consolidated its position at 25.4%, up from 25.1% in 2019 and the only major bank to have grown its share as challenger banks like Macquarie have steadily gained ground on the Big Four. NAB has slipped 1.2 percentage points to 14.1%, and ANZ has fallen 1.4 percentage points to 13.2%. Westpac's 3.2 percentage point decline is more than double the next-largest fall.
Westpac's share erosion has been steady and consistent rather than concentrated in any single moment. From 23.9% in March 2019, the bank fell to 21.7% by March 2022, 21.0% by March 2025, and 20.7% by March 2026. In dollar terms, the book has grown: from $408 billion to $509 billion. But the market has grown faster around it every year.
The period from 2019 to 2022 was the most damaging for Westpac's relative position, with the bank shedding 2.2 percentage points in three years while competitors, particularly CBA and, later, Macquarie, aggressively expanded their broker-originated pipelines. Westpac's broker relationships were significantly disrupted in this period by its response to the Royal Commission into Banking, which included a tightening of credit policy and a temporary withdrawal from some broker segments.
Since 2022 the decline has continued, but more gradually, roughly 0.3 percentage points per year. Westpac has grown its absolute book in each of those years, but not fast enough to maintain share in a market expanding at 6–8% annually. As Westpac's own first-quarter FY26 results confirmed, the portion of mortgages originated through Westpac's proprietary channels dropped to 44.4%, down from 47.3% a year earlier, as brokers take on an ever-larger share of origination at the bank even as the overall book lags the market.
CBA's ability to hold and slightly grow its share while the rest of the big four have all retreated reflects several structural advantages that have compounded over time.
CBA's investment in its proprietary digital platform, CommBank app, and its direct-to-consumer mortgage origination capability has allowed it to capture refinancing activity that might otherwise have flowed through brokers to competing lenders. Its NetBank and Home Loan application technology has consistently rated among the fastest in the market for digital approval times.
CBA grew its mortgage book from $429 billion in March 2019 to $624 billion in March 2026, an increase of $195 billion that represents roughly 26 cents of every new dollar of mortgage lending written in Australia over those seven years.
For mortgage brokers, the divergence in big four performance has practical implications for how they think about lender selection and accreditation maintenance.
Westpac's declining share does not necessarily mean declining service quality or product competitiveness. The bank has invested significantly in its broker proposition under its Westpac and St.George brands in recent years, and its broker channel volumes have grown in absolute terms. That said, Westpac's full-year FY25 results showed home loan growth of just 5%, lagging the broader banking system, with net interest margin slipping amid what the bank itself called "persistent competition" for both loans and deposits. A lender in that position may face internal pressure to reverse the trend, which can translate into pricing aggression or policy flexibility that brokers can leverage for clients.
CBA's growing share, meanwhile, reflects a lender that is winning both broker and direct business simultaneously, a combination that can sometimes create tension around rate differentiation between channels. Brokers who regularly place business with CBA will be familiar with the ongoing need to ensure broker-sourced clients are receiving rates competitive with the bank's direct offers.
NAB and ANZ sit in a middle position, both losing share, but at a more moderate rate than Westpac, and both with significant broker networks that have historically been well regarded for turnaround times and BDM accessibility.
The broader picture from the APRA data is of a big four group that is slowly but steadily losing ground to challengers, with Macquarie alone having captured nearly 5 percentage points of market share since 2019. For brokers, that shift represents both a responsibility and an opportunity: the ability to direct business to the most competitive lender in any given scenario is precisely what clients are paying for. And with higher rates and rising energy costs set to squeeze borrowing capacity further into 2026, the value of that guidance has rarely been more apparent.
