Growing mutual bank IMB Bank added 12,000 new members and grew its net profit by 15 per cent over the 2017-18 financial year, to A$31.6 million. The bank's total assets reached $5.9 billion, with its residential loan and business loan portfolios recording growth over the year of 5.3 per cent and 9.2 per cent, respectively."As well as seeing an increase of 4.1 per cent in our deposit book, the bank achieved record loan approvals in excess of $1.2 billion," said Robert Ryan, IMB chief executive. IMB's efficiency ratio reduced to 66.3 per cent, remaining one of the lowest amongst its mutual ADI peer set, Ryan said. Total expenses increased by 4.5 per cent on the previous year.  Other IMB key metrics:•    average interest margin moved from 2.03 per cent in FY17 to 2.13 in FY18; •    bad and doubtful debts expenses grew slightly to $1.2 million;•    the Group's capital adequacy ratio at 30 June was 16.1 per cent.The IMB Board declared a final dividend of 10 cents per share, to be paid to registered shareholders at the close of trading on 4 September 2018. The full year dividend represents a payout ratio of approximately 76 per cent of shareholders' interest in contributed funding.