Macquarie and Commonwealth Bank are expanding their mortgage books at a far faster rate than their rivals, as increasingly competitive home loan pricing and big cash incentives drive an end-of-year scurry among the country’s biggest banks.

Data released by the prudential regulator shows the mortgage books of at least one of the big four banks receded for the second month in a row, and Macquarie was the biggest winner, having added $1.9 billion to its loan balances in August alone.