Texas Labor Code - LAB § 410.033. Multiple Carriers

(a) If there is a dispute as to which of two or more insurance carriers is liable for compensation for one or more compensable injuries, the commissioner may issue an interlocutory order directing each insurance carrier to pay a proportionate share of benefits due pending a final decision on liability.  The proportionate share is computed by dividing the compensation due by the number of insurance carriers involved.

(b) On final determination of liability, an insurance carrier determined to be not liable for the payment of benefits is entitled to reimbursement for the share paid by the insurance carrier from any insurance carrier determined to be liable.