Legal Definitions - indebitatus assumpsit

Indebitatus assumpsit is a historical legal term from common law, referring to a type of action brought to recover a debt where the defendant had received a benefit and was therefore considered to have an implied promise to pay for it. It literally translates from Latin to "being indebted, he undertook" or "being indebted, he promised."

Unlike a claim based on an explicit, written, or spoken contract, indebitatus assumpsit allowed a plaintiff to recover money when the defendant had been "unjustly enriched" at the plaintiff's expense, even without a formal agreement. The law would infer a promise to pay what was fair and reasonable. While the specific legal action of indebitatus assumpsit has largely been replaced by modern concepts like "unjust enrichment" or "restitution" in contemporary legal systems, the underlying principle remains a fundamental part of contract and quasi-contract law.

Here are some examples illustrating the principle behind indebitatus assumpsit:

• Accidental Overpayment: Imagine a large corporation's accounting department mistakenly processes a duplicate payment to a supplier for a delivered order, sending them twice the agreed amount. The supplier receives the extra funds without having provided additional goods or services.

  This illustrates the principle because, even though there was no explicit agreement for the supplier to return an overpayment, the law would imply a promise to do so. The supplier has been unjustly enriched by the accidental second payment, and the corporation could pursue a claim (based on the principles of indebitatus assumpsit) to recover the excess funds.

• Unsolicited but Accepted Services: Consider a homeowner who hires a landscaping company to mow their lawn and trim their hedges. Due to a mix-up, the landscaping crew mistakenly performs the services on the identical house next door. The neighbor, seeing the work being done, does not object and benefits from the freshly mowed lawn and trimmed hedges.

  In this scenario, the neighbor never explicitly hired the landscapers. However, by allowing the work to proceed and receiving the benefit of the services, the law might imply a promise to pay the reasonable value of the landscaping. It would be unjust for the neighbor to receive the benefit of the work without providing compensation, reflecting the core idea of indebitatus assumpsit.

• Mistaken Delivery and Consumption of Goods: A bakery mistakenly receives a large shipment of specialty flour intended for another bakery down the street. The staff at the receiving bakery, assuming it's a new supplier or a special order, accepts the delivery and uses a significant portion of the flour to bake goods over the next few days.

  Here, the bakery that received and used the flour never ordered it from that particular supplier, so there's no direct contractual agreement. Nevertheless, by accepting and consuming the valuable goods, the bakery has been unjustly enriched. The law would imply a promise to pay the reasonable market value of the flour to the supplier, preventing the bakery from benefiting unfairly at the supplier's expense, which is the essence of the principle embodied by indebitatus assumpsit.