N.C. Gen. Stat. § 58-45-10

There is hereby created the North Carolina Insurance Underwriting Association, consisting of all insurers authorized to write and engage in writing within this State, on a direct basis, essential property insurance, except town and county mutual insurance associations and assessable mutual companies as authorized by G.S. 58-7-75(5) b, 58-7-75(5)d, and 58-7-75(7)b and except an insurer who only writes insurance in this State on property exempted from taxation by the provisions of G.S. 105-278.1 through G.S. 105-278.8. Every such insurer shall be a member of the Association and shall remain a member of the Association so long as the Association is in existence as a condition of its authority to continue to transact the business of insurance in this State.