Written by attorneys · grounded in primary & secondary sources — see below
2 senses
1
An obligation arising between two persons who have not contracted with each other but have formed a relationship similar to a contractual one. The obligation prevents unjust enrichment by requiring restitution for benefits conferred without a formal agreement.
2
Sense 1
1
Sense 1
An obligation arising between two persons who have not contracted with each other but have formed a relationship similar to a contractual one. The obligation prevents unjust enrichment by requiring restitution for benefits conferred without a formal agreement.
Sources & Authorities· 1 source
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Dictionaries
Examples
Sense 2
2
Sense 2
An obligation arising where a payment is made in error. The obligation prevents unjust enrichment by requiring restitution for benefits conferred without a formal agreement.
Sources & Authorities· 1 source
Select any source to read its text and confirm it supports the definition.
An obligation arising where a payment is made in error. The obligation prevents unjust enrichment by requiring restitution for benefits conferred without a formal agreement.
Each sense below has its own examples, sources, and questions.
3
Broken Engagement and Reliance Losses
Gavin promised Grant co-ownership in his shipping company after their marriage and encouraged her to quit her job and pay off company debts in preparation. When Gavin ended the engagement, Grant sued for the value of her unpaid labor and savings. The court treated the claim as arising under a quasi-contractual obligation because the parties had formed a relationship akin to contract through reliance on the marriage promise, allowing recovery of actual expenditures to prevent unjust enrichment.
Inverse Condemnation and Lawful Obligation
A developer spent millions improving coastal property after the city imposed land-use restrictions that prevented any economic use. When the restrictions were later held to constitute a taking, the developer sought compensation measured by the value of the improvements. The court recognized an obligation similar to contract because the developer had conferred a measurable benefit on the city through lawful reliance, requiring payment to avoid unjust enrichment even though no agreement existed.
City of Monterrey v. Del Monte Dunes at Monterrey, Ltd.526 U.S. 687, 734 (1999)
Spousal Contributions to Earning Capacity
During marriage a wife supported her husband while he obtained an advanced degree that dramatically increased his future income. Upon divorce she sought a share of the enhanced earning power created by her efforts. The court analyzed the claim under quasi-contract principles because the marital relationship created an obligation to restore the value of benefits conferred without an express agreement, preventing one spouse from retaining the full enrichment.
In re Marriage of Graham574 P.2d 75, 77 (Colo. 1978)
Frequently Asked4
How does obligatio quasi ex contractu differ from an actual contract?+
It arises without mutual assent or bargained-for exchange when one party confers a benefit on another in circumstances that make retention unjust. Courts impose the obligation to prevent unjust enrichment rather than to enforce a promise.
Supporting sources
What remedies are available under obligatio quasi ex contractu?+
Restitution measured by the reasonable value of the benefit conferred is the usual remedy. Recovery is limited to the enrichment actually received and retained, not expectation damages or lost profits.
Supporting sources
Does the doctrine apply when parties mistakenly believe a contract exists?+
Yes. When parties perform under a mutual mistake that voids the agreement, the performing party may recover the value of benefits conferred on the other under quasi-contract principles to restore the status quo.
Supporting sources
Can breach of promise to marry give rise to this obligation?+
In states that retain the action it is treated as a quasi-contract claim allowing recovery of actual expenditures made in preparation for marriage, though not for expected financial benefits from the marriage itself.
Supporting sources
526 U.S. 687, 734 (1999)Property
…to be the closest cousin to the plurality's conception of § 1983 as applied here, the resemblance is limited by that strain of quasi-contract[^maj-9] theory holding that the defendant must pay for what he has received to avoid unjust enrichment, see E. Farnsworth, Contracts § 2.20, p. 101 (3d ed. 1999), whereas the theory of just…