Industry body Abacus estimates credit unions, building societies and mutual banks recorded housing loan growth of 5.8 per cent over the year to December 2012 - a gain in market share for the sector - while deposit growth was 6.6 per cent.The Abacus data provides a different perspective on trends in the sector to that presented in the Australian Prudential Regulation Authority's quarterly overview (which does not allow for the conversion of some mutuals to banks).APRA put the return on assets for credit unions for the year to December 2012 at 0.5 per cent. The return for building societies over the same period was 0.6 per cent.