Under the rules of the society, admission to membership must be restricted to persons who fall within one or more common bonds appropriate to a credit union (whether or not other qualifications are required). The common bonds are: following a particular occupation; being employed by a particular employer; residing in or being employed in a particular locality; being a member of a bona fide organisation or otherwise associated with other members for a purpose other than forming a society to be registered as a credit union; and any other common bond approved by the FCA.

If the rules so provide, a person who is a member of the same household and a relative of a member who falls directly within a common bond is treated as also falling within that bond. A body corporate, partnership or officer or member of the governing body of an unincorporated association falls within those bonds where its principal business, employment, place of business, significant connection, membership or association meets the specified criteria. The FCA may accept a statutory declaration by three members and the secretary as sufficient evidence that the requirement is met.