Commonwealth Bank of Australia

CBA's net interest income — anchored by the largest retail mortgage book in Australia (~25.4% market share as at April 2025) and the country's largest retail deposit base — drove uninterrupted revenue growth from FY2021 through FY2025. NIM swings with the rate cycle (1.99% in FY2024, 2.08% in FY2025) constrain forward precision.

Retail banking and residential mortgages dominate CBA's revenue, with business banking and New Zealand operations (approximately 13% of group profits via ASB Bank) providing secondary but correlated contributions. The bank lacks the uncorrelated product diversity seen in broader financial conglomerates.

Approximately 87% of CBA's profits originate in Australia, with New Zealand (ASB Bank, fully owned since 2000) contributing roughly 13%. Operations in Asia, the UK, and the US are described as immaterial to consolidated revenue.

Banking requires capital deployment proportional to loan growth, and CBA's cost-to-income ratio rose to 49.2% in FY2025 as technology investment reached A$2.3 billion. The AI-driven efficiency program shows long-term promise but has not yet produced demonstrated operating leverage across a full cycle.

CBA's net interest income is generated from residential mortgages (multi-decade relationship duration) and Australia's largest retail deposit base, providing a high-renewal, structurally sticky revenue stream. Loan impairment expense was A$320 million (7 basis points) in FY2025, reflecting strong underlying credit quality across the current cycle.