Australia's biggest business banker has called the end of the deleveraging cycle and is expecting to see growth in demand for business finance in the second half of this year and throughout 2011.National Australia Bank chief executive Cameron Clyne said yesterday that the bank's Australian SME and institutional pipeline was at its strongest for five years.Clyne said NAB's share of the business banking market and its ongoing investment in its business banking division would ensure that it gets maximum benefit from any pickup in demand for business credit.Unlike its peers, NAB increased lending to business in the past year, if only marginally. The business banking division's gross loans and acceptances were up 1.2 per cent to $184.8 billion in the 12 months to March.Clyne said: "The key variable for us is business credit. If it comes on in the second half it will benefit us."NAB yesterday posted a net profit of $2.09 billion for the six months to March, down 21.4 per cent on the previous corresponding period. The bank's preferred measure, cash earnings, was $2.19 billion, up 8.2 per cent on the previous corresponding period.As with Westpac earlier in the week and ANZ last week, NAB's increase in cash earnings was due largely to a big reduction in the charge for bad and doubtful debts. The bad debt charge was $1.2 billion, down from $2 billion in September and $1.8 billion in March last year.And, as with the other banks, NAB struggled to generate any revenue growth. Net operating income of $8.2 billion for the half was down 1.8 per cent from the $8.4 billion of income reported in the September half and down 3.3 per cent on the previous corresponding period. Expenses grew a little during the half. The banking cost to income ratio rose from 43.4 per cent in March last year to 45.5 per cent in the latest half.The cash return on equity was 12.9 per cent, up from 12.7 per cent in the previous corresponding period.  The business banking division contributed half of the bank's profit, with cash earnings of $1.09 billion. That result was 41 per cent higher than the $776 million of cash earnings reported in the September half and 33 per cent higher than the result in the previous corresponding period.The division's net interest margin rose six basis points from 2.45 per cent in September to 2.51 per cent in the latest half.  Its cost to income ratio fell from 31.1 per cent to 30.3 per cent over the same period, making it the most efficient of NAB's businesses. In comparison, the personal banking division's net interest margin fell from 2.64 to 2.34 per cent over the past six months, and its cost to income ratio rose from 47.5 per cent to 55 per cent.Despite plenty of competition in the SME market, NAB has increased its share. According to RBA figures, its share of business lending was 20.4 per cent in the March half, up from 19.6 per cent in the previous