The bank funding gap in Australia is expected to decline around 14% over the next 12 months to around AU$1 trillion by June 2027 from around AU$1.2 trillion, as tax changes lead to slower credit growth, BofA Securities said in a Thursday note.

Changes to capital gains tax and negative gearing are expected to materially slow investor mortgage lending. Investors accounted for around 40% of mortgage flows over the past year. Consecutive central bank hikes and negative sentiment have weighed on the housing market, with house prices expected to remain flat this year.

The recent strength in deposit growth is expected to continue. Slower credit growth should reduce banks' demand for high‐quality liquid assets, which has been a key support for semis. A narrower bank funding gap implies reduced bank bill issuance.

Banks have reduced their reliance on wholesale funding in recent years, while deposits as a proportion of total funding improved to 67.5%, the note said. Commonwealth Bank of Australia (ASX:CBA) has the strongest customer deposit base, with deposits accounting for 79.4% of funding.