Long before I was an attorney, I heard this tale that if you endorsed a check that had the words “PAID IN FULL” written on the check, then you were accepting the check as full payment of what was owed. But I had never really thought about that legal principle because, “People don’t really do that, do they?”

In Triangle Construction Co. v. Fouches and Assoc., the Court of Appeals of Mississippi recently held that the PAID IN FULL principle—or what lawyers know as accord and satisfaction—barred a contractor’s claim for additional payment. The contractor won a bid to construct a water system in two local counties. Following completion of the project, the contractor filed a claim against the owner and engineer for damages allegedly resulting from the negligence of the owner and engineer.

Upon completion of the project, the owner sent contractor a check marked “Final Payment,” but the check did not compensate the contractor for its increased construction costs as a result of the delays or for the extracontractual project expansion. The contractor conceded that it cashed the check, but argued that it repeatedly asserted to the owner—including in a letter sent to then engineer—that it did not consider the “final payment” to be final and that it would continue seeking the remainder of what it was owed.

The court disagreed. Under Mississippi law, despite what the parties may argue was their intent, cashing a check marked “final payment” constitutes an accord-and-satisfaction agreement, which precludes that party from bringing future claims for additional payment. In Triangle Construction, the court held that the contractor’s claims against the engineer were barred by the doctrine of accord and satisfaction.

So, the “paid in full” principle is not just an old wives’ tale. Depending on your state’s law, if you negotiate a check that is marked “paid in full” or even “final payment” then you are risking the fact that you may be settling any claims you have. If you are a contractor that seeks to reserve those claims, then don’t cash the check if it is marked with special language on it.