Macquarie Bank is one bank leading an indifferent mortgage market, with the bank growing its home loan book at rates well above system.APRA's monthly banking statistics, for March 2018, show Macquarie's growth streak centred on residential investment lending.The regulators' patrols on investment lending and interest-only lending across the sector have made banks overall timid lenders.Investment lending by all banks lifted by a trivial 0.1 per cent over March 2018 compared with February, and increased by 1.7 per cent over 12 months, the APRA data shows.The combined home loan book of all Australian banks rose by 5.4 per cent over one year. The RBA put aggregate mortgage credit growth at 6.0 per cent over the year to March, meaning non-bank funders are gaining share.Macquarie, on APRA data, lifted investment lending in March by 1.7 per cent during a month in which ANZ and Commonwealth Bank reported shrinking portfolios and NAB no growth at all.Westpac stood apart from its peers with investment lending growth of 0.5 per cent.Over the six months to March, Westpac, NAB and ANZ all broadly matched bank sector growth in mortgages of 2.7 per cent.Commonwealth Bank, which has been shedding market shares in mortgages continues to do so. CBA accounted for 27.1 per cent of all mortgages funded by banks at June 2017. This has slumped to 26.4 per cent.