Falling interest rates did not do much to slow the inflow into Macquarie Group's deposit products during the September half.Macquarie reported that total deposits in its banking and financial services division grew 5 per cent to A$52.6 billion during the six months September. This included $29.7 billion in its cash management account - an increase of 9 per cent.The division has 1.5 million customers and 640,000 of them have deposit accounts. The average cash management account balance is $42,000.Business banking deposits grew by 1 per cent.On the mortgage side, Macquarie's retail mortgage book grew 9 per cent during the September half to $38.8 billion. Macquarie Bank has a 2.3 per cent share of the mortgage market, according to APRA data.Macquarie said there was a 14 per cent increase in the volume of new business. Mortgage growth was driven by demand in the lower loan-to-valuation ratio and owner-occupier segments.The Australian vehicle finance portfolio fell 3 per cent to $14.7 billion due to a fall in new car sales.Macquarie Group reported a net profit of $1.4 billion for the six months to September - an increase of 11 per cent on the previous corresponding period but down 13 per cent on the March half.The banking and financial services division made a net profit of $385 million - an increase of 2 per cent on the previous corresponding period.The weak spot was Macquarie's market-facing businesses, while its annuity-style activities, which include banking, reported growth half on half and year on year.