A member is a shareholder of a credit union who is entitled to voice and vote in the decision-making process, regardless of the amounts of their credit union deposits. Under the principle of democratic ownership, every member can also participate in making policy and regulation of the credit union if he/she is elected onto the board of directors. There were 5.9 Million members at the end of 2012.

A Credit Union is a non-profit financial cooperative which offers a wide range of banking services to members. According to each field of membership, credit unions are classified into community, employee, and association/group based credit unions. Other than financial services, a credit union promotes community development through education, social activities, and by providing funding to disadvantaged people.

The National Credit Union Federation of Korea is a non-profit institution which is an apex trade association, financial intermediary, and business organization consisting of all CUs, and was established in 1964.

As a trade association, NACUFOK represents member credit unions to the government, the regulator, and the international credit union society. It conducts publicity, supervision, management consulting and education. As a financial intermediary NACUFOK manages an interlending service as a central financial facility, and it invests the surplus funds in high grade mutual funds, government and corporate bonds, and other securities.

Finally, NACUFOK offers a variety of mutual insurance services to members with 76 products & 1,035,313 contracts via credit unions. NACUFOK's solvency margin ratio, adapted to the EU based solvency margin method is 393.73% dated on Dec. 31, 2012.