IMB Bank says it has defied the low rate environment, subdued trading conditions in the housing market and intense competition from other lenders to deliver a flat full year profit.The bank said on Monday that it posted a net profit of A$31.7 million in the 12 months to the end of June - up $100,000 on the 2018 bottom line.Chief executive Robert Ryan described the result as "strong" even though better-than-system expansion in lending volumes was only sufficient to keep the earnings outcome more or less in line with last year."I am especially pleased that the bank's deposit and loan portfolios have grown strongly in a challenging environment and that we have delivered significant initiatives improving customer experience and sustained our community support while maintaining robust business metrics," he said.The quirk in IMB's commentary about its 2019 performance is that profit growth was subdued despite improved lending volumes and no erosion of the net interest margin.IMB reported a 7 per cent rise in the size of its mortgage book and a 12 per cent increase in commercial lending - well ahead of system growth rates.And its net interest margin was steady at 2.12 per cent.Net interest income came in at $125 million - up 3 per cent on last year. But this improvement was nullified by a fall in non- interest income and a $2.9 million rise in salary costs and other operating expenses.IMB chair Noel Cornish told shareholders in the annual report published last week that the bank was on track to complete a merger of its operations with the Hunter United Employees' Credit Union early in 2020.If the deal is approved by members, Hunter United is expected to boost IMB's membership base by 9000 and its asset base by $334 million.Cornish also highlighted the bank's active approach to capital management during the year, which saw a further 1.86 million shares repurchased from members.IMB has now bought back 16 million shares or 40 per cent of the scrip it issued previously to shareholders.Cornish said the timing of future buybacks would be considered having regard to the capital and operational requirements of the company. Members with shares in IMB will receive a final dividend of 10.5 cents per share  - up half a cent on the 2018 final dividend.