## Facts

- Precision Heavy Haul, Inc. bought a specialized heavy-load trailer manufactured by Trail King Industries, Inc.
- Precision alleged negligent design/manufacture caused the trailer to fail while hauling a large transformer, damaging the trailer and the transformer.
- Precision sued for negligence, strict products liability, and breach of warranty, seeking recovery of economic losses.
- Trail King denied liability and asserted comparative negligence/assumption of risk, alleging Precision negligently used or altered the trailer.
- Precision presented itemized damages totaling $694,550.87, including transformer repair costs owed to its customer and related out-of-pocket expenses (e.g., crews, lodging, meals, equipment rental).
- Trail King did not dispute the arithmetic accuracy of the $694,550.87 figure, focusing instead on liability and comparative fault.
- The jury found Trail King 100% at fault and awarded $694,550.87.

## Issues

1. Whether a damages claim is “liquidated” for prejudgment-interest purposes when the amount is exactly calculable but liability and comparative fault are contested.
2. Whether the assertion of comparative fault renders an otherwise liquidated claim “unliquidated,” defeating prejudgment interest.

## Decision

- The court reversed the denial of prejudgment interest and remanded for entry of prejudgment interest.
- Precision’s damages were liquidated because the evidence supplied data allowing exact calculation without opinion or discretion.
- Trail King’s comparative-fault defense did not convert the claim into an unliquidated one because it challenged responsibility for payment, not the computation of the damages amount.
- Denying prejudgment interest solely due to comparative-fault disputes would conflict with Arizona law distinguishing uncertainty in liability from uncertainty in the amount of damages.

## Legal Principles

- Prejudgment interest is available as a matter of right on liquidated claims.
- A claim is liquidated when the evidence furnishes data that permits computing the amount with exactness, without reliance on opinion or discretion.
- Disputes about liability, including comparative fault and apportionment of responsibility, do not defeat prejudgment interest if the damages amount is objectively determinable.
- The purpose of prejudgment interest is compensatory: to reimburse the plaintiff for loss of use of money due from the time the claim became payable.

## Conclusion

Because Precision’s damages were proven through precise, itemized data and were not challenged as mathematically inaccurate, the claim was liquidated; Trail King’s comparative-fault defense affected only allocation of responsibility and did not bar prejudgment interest, so the case was remanded to calculate and award that interest.


Precision Heavy Haul, Inc. v. Trail King Indus., Inc., 228 P.3d 895 (Ariz. Ct. App. 2010)