Whether a party is entitled to pre-judgment interest is within the trial court's discretion. Lyon Metal Products v. Protection Mutual Insurance, 747 N.E.2d 495 (2nd Dist. 2001).
The Illinois Interest Act provides that creditors shall be allowed interest at the rate of five percent per annum "for all monies after they become due on any . . . instruments of writing." Under long-standing case law, to be entitled to pre-judgment interest on a claim based on a written instrument, the sum due must be liquidated or subject to easy determination by calculation or computation.
The case involved a claim under an insurance policy for business interruption losses. In denying pre-judgment interest, the Court reasoned that since the jury awarded significantly less than the amount claimed by the insured, the sum due under the business interruption endorsement to the policy was not "easily determined." A trial court's decision on this question will be affirmed on appeal absent an abuse of discretion.