Banking analysts are encouraged by the steady growth in business lending this year, which offers the prospect of higher interest margins for lenders with a big exposure to the business sector.Figures released by the Reserve Bank and the Australian Prudential Regulation Authority last week show that business lending growth has been trending ahead of housing over the past four months.In a note on the figures, Deutsche Bank said the strong business-lending trend implied "a positive mix effect" for margins. The APRA figures show that business loan balances grew 1.9 per cent for the three months to June - an annualised rate of 7.6 per cent. For the 12 months to June, growth was 7.3 per cent.Throughout 2011 business lending figures were flat or negative.In the three months to June, ANZ's business loan book grew at an annualised rate of 15 per cent, followed by Westpac at 10 per cent, NAB at four per cent and Commonwealth at three per cent.NAB has the most to gain from a rebound in business lending because it has greater exposure. According to Deutsche Bank's figures, 38.5 per cent of NAB's loans are business loans, compared with 31.8 per cent for ANZ, 23.2 per cent for Commonwealth and 21.6 per cent for Westpac.Among the smaller banks, 27.8 per cent of Suncorp's loans are business loans, compared with 27.3 per cent for Macquarie Group, 20.5 per cent for Bendigo and Adelaide Bank, and 17.9 per cent for Bank of Queensland.Deutsche's "top picks" in the sector are ANZ, Commonwealth and Bank of Queensland - all rated Buy.In its comment on the business lending data, Goldman Sachs said: "The business sector is starting to once again generate more normal rates of growth after an extended period of deleveraging and disintermediation."Weaker profitability in the mining sector makes it more difficult to fund out of retained earnings. This has increased the call on the banking sector."