Okla. Stat. tit. 12, § 12-729.10: 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

this state.

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 this state governing a failure to make or accept an offer of

settlement or offer of judgment, or 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 this state.