Tenn. Code Ann. § 56-41-105: Plan of operation - Insurers and agents required to participate

(a) The plan of operation shall require participation by all insurers licensed in Tennessee and transacting direct insurance of the type covered by the specific plan, and all agents appointed to represent the insurers in this state for the specified types of business, except that the commissioner may exclude classes of persons for administrative convenience or because it is not equitable or practicable to require them to participate in the plan. "Type of insurance" means personal or commercial property and casualty coverage as defined in this title.

(b) The plan may provide for optional participation by insurers not required to participate under subsection (a).