(a) With respect to a foreign-money claim, recovery of pre- judgment or pre-award interest and the rate of interest to be applied in the action or distribution proceeding, except as provided in subsection (b), are matters of the substantive law governing the right to recovery under the conflict-of-laws rules of this State.
12-639.Pre-judgment and judgment interest.
Article XII. Judgments - Enforcement · Part 6. Foreign Judgments and Foreign-Money Claims · Not amended since adoption on record · Last verified July 20, 2026
In one sentenceLeaves prejudgment interest on a foreign-money claim to Illinois's ordinary substantive law, but lets a court adjust it for delay or a rejected settlement offer, and applies Illinois's standard rate once judgment enters.
Full Text of 735 ILCS 5/12-639
(b) The court or arbitrator shall increase or decrease the amount of pre-judgment 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.
Plain-English Summary
Interest questions split into two stages. Subsection (a) leaves the availability and rate of prejudgment or pre-award interest to whatever substantive law governs the underlying claim under Illinois's conflict-of-laws rules — the currency of the claim doesn't change that analysis.
Subsection (b) carves out one exception: a court or arbitrator must adjust prejudgment interest to reflect Illinois law on offers of settlement or judgment, or on a party's conduct that caused undue delay or expense. That keeps the Act from undercutting Illinois's own incentives for prompt, good-faith litigation conduct regardless of what currency the claim is measured in.
Once judgment enters, subsection (c) applies Illinois's standard judgment-interest rate to a foreign-money judgment just as it would to any other Illinois judgment.
Frequently Asked Questions
What law governs prejudgment interest on a foreign-money claim?
The substantive law that would otherwise govern the claim under Illinois's conflict-of-laws rules, except as adjusted under subsection (b).
Can a court increase or decrease prejudgment interest for a party's conduct?
Yes. Subsection (b) requires the court or arbitrator to adjust interest to the extent Illinois law on undue delay or expense caused by a party or its attorney requires.
Does Illinois's offer-of-settlement or offer-of-judgment law affect interest on a foreign-money claim?
Yes, subsection (b) specifically ties the interest adjustment to a failure to make or accept such an offer.
What interest rate applies once judgment is entered on a foreign-money claim?
The same rate applicable to judgments of this State generally, under subsection (c).
Does the foreign currency of the claim itself change the interest analysis?
No. The currency of the claim doesn't alter which law governs interest; it only affects the currency in which the resulting interest amount is expressed.
Amendment History
(Source: P.A. 86-1291.)
Source & verification. Section text and amendment history are
reproduced verbatim from the Illinois Compiled Statutes, published by the
Illinois Compiled Statutes, Illinois General Assembly / Legislative Reference Bureau. Last verified July 20, 2026.
· Official source
Also known as: prejudgment interest on a foreign currency claim Illinoisjudgment interest rate for foreign money claimoffer of settlement interest adjustment Illinoisinterest rate on a foreign-money judgment