ASB's mortgage book shrinks as ANZ, Kiwibank grow market share

That meant ASB's mortgage book fell to $73.75 billion at Sept 30, putting its market share at 21.38%, down from 21.57% in June and compared with 21.75% in September last year.

A one percentage point share of the mortgage market was worth $$3.46 billion at Sept 30.

Earlier this year, ASB's owner, Commonwealth Bank of Australia, very publicly complained about “unsustainable returns” from mortgage lending in NZ.

It's no mystery why ASB is losing market share.

ASB is currently offering higher interest rates on both six-month fixed and one-year fixed mortgages than the other banks at 7.45% for both periods compared with the other major banks offers ranging from 7.3% to 7.39% for owner-occupiers with at least 20% equity.

Overall, net new mortgage lending in the quarter grew by $3.08 billion to $345.61 billion with ANZ Bank New Zealand leading the growth.

ANZ lent a net $1.49 billion in home loans in the latest quarter, accounting for 48.4% of the new mortgage lending and taking its mortgage book to $105.15 billion and 30.4% of the market.

The government-owned Kiwibank grew its book at more than double is market share, adding a net $559.7 million in new mortgages, accounting for 18.2% of net new lending and taking its total book to 25.11 billion, giving it a market share of 7.26%.

Bank of New Zealand grew its book at a slightly faster clip than its market share, writing a net $585.7 million in new mortgages, 19% of the total new mortgage lending, and taking its book to $57.75 billion and its market share to 16.7%.

Westpac, which had a market share of 18.96% at Sept 30 with a $65.53 billion mortgage book, accounted for just 2.9% of net new lending, adding a meagre $88.2 million in net new mortgages in the latest quarter.