(a) If an operator or other employer fails or refuses to pay any or all benefits due under the terms of an initial determination by a deputy commissioner (725.420), a decision and order filed and served by an administrative law judge (725.478) or a decision filed by the Board or a United States court of appeals, including any penalty awarded in addition to benefits in accordance with 725.607, such operator shall be liable for simple annual interest on all past due benefits computed from the date on which such benefits were due and payable, in addition to such operator's or other employer's liability as is otherwise provided in this part. On claims filed on or after January 1, 1982, in which the payment of retroactive benefits has been withheld pending final adjudication of liability in accordance with section 422(d) of the Act as amended, interest on such withheld retroactive benefit payments shall begin to accumulate 30 days after the date of the first determination that such an award should be made. The first determination that such an award should be made may be a deputy commissioner's initial determination of entitlement, an award made by an administrative law judge or a decision by the Board or a court, whichever is the first such determination of entitlement made upon the claim. Except as provided in paragraph (b) of this section, interest payments owed under this paragraph shall be made directly to the beneficiary. However, an operator or other employer shall have no obligation to pay interest except with respect to benefits which it has either agreed to pay or it has been directed to pay by an order which has become final.
(b) If an operator or other employer fails or refuses to pay any or all benefits due pursuant to an award of benefits or an initial determination of eligibility made by the deputy commissioner and the Fund undertakes such payments, such operator or other employer shall be liable to the Fund for simple annual interest on all payments made by the Fund for which such operator is determined liable, computed from the first date on which such benefits are paid by the Fund, in addition to such operator's liability to the Fund, as is otherwise provided in this part. Interest payments owed pursuant to this paragraph shall be paid directly to the Fund.
(c) The rates of interest applicable to paragraphs (a) and (b) of this section shall be computed as follows:
(1) For all amounts outstanding prior to January 1, 1982, the rate shall be 6% simple annual interest;
(2) For all amounts outstanding for any period during calendar year 1982 the rate shall be 15% simple annual interest; and
(3) For all amounts outstanding during any period after calendar year 1982 the rate shall be simple annual interest at the rate established by section 6621 of the Internal Revenue Code of 1954 which is in effect for such period.
(d) The Fund shall not be liable for the payment of interest under any circumstances, other than the payment of interest on advances from the United States Treasury as provided by section 9501(c) of the Internal Revene Code of 1954.

[48 FR 24294, May 31, 1983]