Mortgage lending in the Australian Prudential Regulation Authority's high-risk categories fell in the March quarter, with reductions in the proportion of new interest-only loans and high loan-to-valuation loans. However, the proportion of new investment loans rose.According to APRA's latest report on the property exposures of authorised deposit-taking institutions, total new housing loans during the March quarter were worth $81.6 billion, compared with $97.4 billion during the December quarter.Investment loans made up 31.4 per cent of the total value of new housing loans in the March quarter, compared with 29.8 per cent in the December quarter.Loans with LVRs between 80 per cent and 90 per cent made up 13.8 per cent of the value of new housing loans during the March quarter, compared with 14.5 per cent in the December quarter.Loans with LVRs above 90 per cent made up 8.7 per cent of the total - unchanged from the December quarter.Interest-only loans made up 34.8 per cent of total new lending, compared with 36.5 per cent during the December quarter.Low-doc loans made up 0.3 per cent of the total - unchanged from the December quarter.