IMB has managed to offset the effects of an erosion in its margins and a rise in the level of liquid assets over the December 2011 half and post a mild increase in net profits. The building society said its profit increased to A$15.13 million over the half, compared with $15.07 million in the corresponding half in 2010.The average interest margin was 2.02 per cent over the half, a slight decline on 2.05 per cent in the 2011 financial year. New lending over the half was $354 million, about 10 per cent lower than the year before. Deposits declined by about one per cent to $3.5 billion.Taking into account the placement of $202 million in commercial mortgage-backed securities in November, IMB puts its liquidity level at 29 per cent, a rise of two percentage points over the half.Six months ago IMB said it was preparing itself for higher capital and liquidity requirements under Basel III. At the time of the June 2011 full year result this saw the Wollongong-based building society cut its dividend to 15 cents a share for the full year, from 19 cents.For the interim profit, IMB maintained the dividend at 10 cents a share.In the review of its interim profit, IMB put its capital ratio at 14.0 per cent at the end of December 2011, up from 12.0 per cent six months before. The placement of the CMBS helped increase this ratio.IMB has a goal of lifting its capital ratio to 15 per cent.The building society also has a "broad-based review of IMB's capital structure options" underway, Michael Cole, chair of the board of directors, wrote in the review of the interim financial results.Grant Samuel, an investment bank and Watson Mangioni, a Sydney law firm, are working on the review.Cole wrote that the review was "well progressed and it is expected it will be finalised in the coming months.