(a) Accrued but unpaid income benefits are those benefits which either:
  (1) have accrued during a period of dispute over insurance carrier (carrier) liability for the claim or injured employee entitlement to the benefits; or
  (2) have not been paid by the date the carrier was required to pay them.
(b) Carriers shall include simple interest in all payments for accrued but unpaid income benefits.
(c) Income benefits accrue in either weekly or monthly pay periods, as otherwise provided by the Texas Workers' Compensation Act and this title, and interest shall be calculated separately for each pay period based on the length of time the benefits for that pay period remained accrued and unpaid.
  (1) For pay periods in which benefits accrued while in dispute as provided in subsection (a)(1) of this section, the carrier shall pay interest for number of days between the seventh day after the day the benefits accrued and the day the payment was made.
  (2) For pay periods in which benefits accrued and were paid late by the carrier as provided in subsection (a)(2) of this section, the carrier shall pay interest for the number of days between the due date for the payment and the date the payment was made.
(d) The rate of interest to be paid on accrued but unpaid income benefits by carriers will be the rate calculated in accordance with the Texas Labor Code, §401.023 and in effect on the date the payment was made.
(e) The following method shall be used to calculate the simple interest to be paid:
  (1) multiply the rate of interest by the amount in question (to create annual amount of interest);
  (2) divide the annual amount of interest by 365 (to create daily interest amount); then
  (3) multiply daily interest amount by the number of days of interest that are owed.

Source Note: The provisions of this §126.12 adopted to be effective December 26, 1999, 24 TexReg 11399