Okla. Stat. tit. 12, § 12-729.9
Rate of exchange
The rate of exchange prevailing at or near the close of business
on the day the distribution proceeding is initiated governs all
exchanges of foreign money in a distribution proceeding. A foreign-
money claimant in a distribution proceeding shall assert its claim
in the named foreign money and show the amount of United States
dollars resulting from a conversion as of the date the proceeding
was initiated.