The Australian Prudential Regulation Authority is "open" to credit unions forming a joint-venture approved deposit-taking institution that combines their balance sheets.An APRA general manager, Stephen Glenfield, told delegates at the Abacus conference, held in Adelaide yesterday, that the regulator had an "open mind" on the idea.News emerged this week that a group of 22 credit unions is investigating the feasibility of setting up a new ADI in which they would all hold shares. They would use the new ADI to combine their balance sheets to raise funds in the capital markets.The chief executive of Service One Credit Union, Peter Carlin, said yesterday that the project was still in its first phase - developing a model and testing it out.Carlin, who is chairing the project group, said he hoped to move into phase two, the due diligence stage, by December.He said the group was targeting a combined balance sheet of about $4 billion and would need a minimum of $3 billion to make the project viable.The main purpose of the project is to allow small credit unions to access wholesale funds at a reasonable cost.Carlin said: "We are concentrating on the asset and liability side of this but we may look at other issues. One thing to consider would be a common computer system."Credit union services company Cuscal is also involved in the group and may be a shareholder in the new ADI if it goes ahead.