28 Tex. Admin. Code § 21.1102
Each issuer of a health benefit plan shall provide a certification of coverage in accordance with § 21.1103 of this title (relating to Timing of Issuance of Written Certificate of Creditable Coverage to an Individual) through § 21.1108 of this title (relating to Notification of Creditable Coverage and Preexisting Condition Exclusion), as necessary to determine the period of applicable creditable coverage of health benefit plans. An issuer of a health benefit plan may enter into an agreement with a third party administrator or plan sponsor for the purpose of providing a certification of creditable coverage as provided in this subchapter. The agreement may provide that the requirements of this subchapter may be complied with by either the issuer of the health benefit plan or a third party administrator or plan sponsor on behalf of the issuer. If an issuer of a health benefit plan enters into an agreement with a third party administrator or plan sponsor under this section, it is the issuer of the health benefit plan's responsibility to meet the requirements of this subchapter or to assure that the requirements are met.
28 Tex. Admin. Code § 21.1102