Tex. Insurance Code § 463.151

(a) The association shall assess member insurers, separately for each account under Section 463.105, in the amounts and at the times the board determines necessary to provide money for the association to exercise the association's powers, perform the association's duties, and carry out the purposes of this chapter. The association may not authorize and call an assessment to meet the requirements of the association with respect to an impaired or insolvent insurer until the assessment is necessary to carry out the purposes of this chapter. The board shall classify assessments under Section 463.152 and determine the amount of assessments with reasonable accuracy, recognizing that exact determinations may not always be possible.

(a-1) The association shall notify each member insurer of its anticipated pro rata share of an authorized assessment not yet called not later than the 180th day after the date the assessment is authorized.

(b) An assessment is due on the date the association specifies, which may not be earlier than the 30th day after the date the association gives written notice of the assessment to member insurers. Interest accrues on an unpaid amount at a rate of 10 percent beginning on the due date.

(c) An insurer whose certificate of authority to engage in business in this state is revoked or surrendered remains liable for any unpaid assessment made before the date of the revocation or surrender.