The purpose of Shared Interest is to provide financial services to fair trade organisations, principally by providing the working capital to fund transactions between producers and retailers. It was launched with a £100,000 loan from Traidcraft, Joseph Rowntree Charitable Trust and Oikocredit, a co-operative based in the Netherlands established by the World Council of Churches to offer micro-finance in developing countries. Oikocredit had already established the practice of community investment and engagement, encouraging its members to provide the capital it required and to play an active part in its management.

Shared Interest registered as an IPS community benefit society and soon had 200 members and £300,000 of capital, inherited from an Oikocredit sister organisation based in Scotland. By 1994, Shared Interest had raised over £4m from its members and was ready to establish its own clearing house with the International Fair Trade Association. Since then, the number of members and the amount these members have invested has grown steadily. The most recent figures available, for 2006, show there were over 8,400 members with £20.5m in withdrawable share capital and a further £3.6m in repayable loan stock members in 2006 was £2,440. During that year, 336 new members joined the society and 288 members withdrew from membership, representing a membership turnover rate of less than 4%. Share capital withdrawals for 2006 were £1.5m, or approximately 7.5% of total share capital. However, this was more than replaced by the inflow of new investment for the year, totalling £2.7m. Members must give six months notice for withdrawals. Interest is payable on share capital, set at bank base rate minus 4%; its current interest rate is 1.5%.

Members are encouraged to get actively involved in the society by becoming Shared Interest Ambassadors. This involves activities such as speaking to groups, staffing exhibition stalls, distributing leaflets and generating local media coverage. Ambassadors are given training and a resource pack, along with support from a team at head office. Shared Interest has now set itself the ambitious target of increasing member investment to £75m by the end of 2012.