ANZ has overtaken National Australia Bank as the pace-setter in the mortgage market, while Commonwealth Bank and Westpac are losing share.According to the latest Australian Prudential Regulation Authority banking statistics, released on Monday, ANZ has increased the size of its mortgage portfolio by 5.1 per cent over the six months to March - more than double system growth, which sits at 2.3 per cent.NAB's mortgage book has grown by 3.6 per cent over the same period. Over the past three months NAB's book has grown 1.5 per cent - just a little ahead of system growth of 1.3 per cent.At one stage last year NAB's mortgage business was growing at three times the rate of system growth CBA has matched system over the past six months, but in the past two months it has dropped to half the rate of system growth. Westpac is the real laggard. Its book grew just 0.1 per cent over the six months to March. Its current growth rate is about half system.Among other lenders, AMP Bank, Citibank and Suncorp have grown ahead of system.Bank of Queensland, Bendigo and Adelaide Bank and HSBC have been growing in line with system, while ING Direct and ME Bank have lagged behind.APRA's figures show that household deposit growth continues to outstrip mortgage lending growth. Total bank retail deposits grew by 8.2 per cent in the 12 months to March, compared with mortgage lending growth of 5.8 per cent over the same period.In the past six months, total retail deposits grew by 4.4 per cent, while mortgages grew 2.3 per cent.During the six-month period, AMP Bank, ANZ, Investec, ME Bank, NAB, Rabo Direct and Suncorp increased their deposit books ahead of system.