TSB's general disclosure statement (GDS) shows its mortgage book, using the same capital adequacy-based measure Good Returns has used since December 2002, grew by $24.5 million to $2.32 billion in the three months ended December.

Wesptac's change in how it calculates its equivalent figures will mean these December quarter figures for all banks will be so distorted as to be meaningless but, unlike Westpac, other measures of TSB's mortgage book are entirely consistent with the capital adequacy-based measure. (Its note on loans and advances to customers exactly matches while its figures on loan-to-valuation ratios show slightly lower totals because they don't include past due and impaired mortgages.)

Reserve Bank figures, which often don't marry at all well with figures derived from all the home-lending banks' GDSs, show all bank lending on housing grew $422 million in the December quarter. But based on those figures, TSB accounted for 5.8% of new mortgage lending by banks in the quarter.

Of TSB's mortgage book at December 31, 18.1% had loan-to-valuation ratios (LVRs) above 80%, up from 16.4% three months earlier. Much of those loans, $231,028, were government-backed Welcome Home loans.

TSB's interest paid on deposits rose 17.8% while interest its customers paid on loans and advances increased only 4.7%, contributing to net profit for the quarter falling 15.6% to $10.4 million.

TSB's charges against profit for bad loans are falling, in line with other banks. Such charges fell to $0.9 million in the latest three months from $2.2 million in the December quarter last year.