D.C. Code § 15-908: Prejudgment and judgment interest.

(a)

With respect to a foreign-money claim, recovery of prejudgment or pre-award interest and the rate of interest to be applied in the action or distribution proceeding, except as provided in subsection (b) of this section, are matters of the substantive law governing the right to recovery under the conflict of laws rules of the District.

(b)

The court or arbitrator shall increase or decrease the amount of prejudgment or pre-award interest otherwise payable in a judgment or award in foreign money to the extent required by the law of the District governing a failure to make or accept an offer of settlement or an offer of judgment, or to the extent required by the law of the District governing conduct by a party or its attorney causing undue delay or expense.

(c)

A judgment or award on a foreign-money claim bears interest at the rate applicable to judgments of the District.