Texas Insurance Code - INS § 101.202. Attorney's Fees

(a) In an action against an unauthorized insurer or unauthorized person on a contract, agreement, or arrangement of insurance issued or delivered in this state to a resident of this state or to a corporation authorized to do business in this state, the court may award to the plaintiff a reasonable attorney's fee if:

(b) An unauthorized insurer's or person's failure to defend an action described by Subsection (a) is prima facie evidence that the failure to make payment was vexatious and without reasonable cause.