(a) Interest required. Prejudgment interest shall be due on any sum required to be paid pursuant to an order of disgorgement. The disgorgement order shall specify each violation that forms the basis for the disgorgement ordered; the date which, for purposes of calculating disgorgement, each such violation was deemed to have occurred; the amount to be disgorged for each such violation; and the total sum to be disgorged. Prejudgment interest shall be due from the first day of the month following each such violation through the last day of the month preceding the month in which payment of disgorgement is made. The order shall state the amount of prejudgment interest owed as of the date of the disgorgement order and that interest shall continue to accrue on all funds owed until they are paid.

(b) Rate of interest. Interest on the sum to be disgorged shall be computed at the underpayment rate of interest established under Section 6621(a)(2) of the Internal Revenue Code, 26 U.S.C. 6621(a)(2), and shall be compounded quarterly. The Commission or the hearing officer may, by order, specify a lower rate of prejudgment interest as to any funds which the respondent has placed in an escrow or otherwise guaranteed for payment of disgorgement upon a final determination of the respondent's liability. Escrow and other guarantee arrangements must be approved by the Commission or the hearing officer prior to entry of the disgorgement order.