Bankstown City Credit Union, one of the best capitalised ADIs in the country, is working toward a merger with Maritime, Mining & Power Credit Union.The enlarged entity will have in excess of A$1 billion in assets when the merger completes during the first half of 2017, if members and regulators concur.The boards of BCCU and MMPCU said on Friday they had entered into a memorandum of understanding that would "enable each entity to work together on merging the two organisations."Raad Richards, chair of BCCU, invoked cost and investment burdens as a key rationale for the merger with MMPCU, an entity five times its size. Richards (also the chief executive of aged care provider Carrington Centennial Care) wrote in a media release that "industry developments are making it progressively harder for smaller organisations to cost effectively service their members to the desired standard."He emphasised as factors "the disproportionate burden of regulation and compliance, the need to heavily invest in emerging technologies and products, and the difficulty in attracting new, younger clients to the credit union brand as key pressures being experienced by smaller credit unions."For MMPCU, the merger with BCCI will be its sixth amalgamation since 2010. The name of the merged identity will be Maritime, Mining & Power Credit Union, though MMPCU will continue to trade locally as "Bankstown", taking parochial brand names under its wing to four.Reliance Credit Union and Collie Miners Credit Union continued as divisions of MMPCU following their own mergers in 2010 and 2015.The three other minnows folded into MMPCU were Gosford City Credit Union six years ago, Newcom Colliery Employees' Credit Union last year and Shell Employees' Credit Union in a merger formalised in April.MMPCU is on a complementary path to adopt "mutual bank" status and branding, with members to be asked to vote on the shift later this year. Maritime will be the seventeenth credit union to do so.Maritime is also a rare mutual successfully wooing both industrial and community bond mutuals in recent years."Both credit unions are in a strong financial position," Friday's media release declared.BCCU put its risk-weighted capital adequacy as at 30 June 2015 being 25.5 per cent and 25.0 per cent at June 2016, nine percentage points ahead of the sector average.Profitability for BCCU, however trails industry averages, with a return on assets of 0.25 per cent compared with 0.4 per cent for the sector.MMPCU, meanwhile, operates on capital ratios and profit levels more in line with the industry average.Maritime's busy merger schedule may be about to lead it to a four figure asset base (measured in billions), but at $1 billion or so this mutual remains in the middle of a credit union ranking dominated, as ever by titans from Queensland, South Australia, Victoria and MMPCU's Sydney compatriot Teachers Mutual Bank.