Unjust enrichment is often described in simple moral terms: one person should not unfairly profit at another’s expense. The legal doctrine is more disciplined than that slogan. Not every benefit is unjust, and not every unequal outcome creates a claim. The task is to identify a specific enrichment, connect it to the claimant’s loss or contribution, and explain why the recipient lacks a sufficient legal basis to retain the value.
The Benefit
The first question is what the defendant received. The benefit may be money, property, services, discharge of an obligation, improvement of an asset, or another measurable form of value. The claimant should identify the enrichment with precision rather than relying on a general assertion that the defendant became better off.
At the Claimant’s Expense
The enrichment must also be connected to the claimant. If a stranger happens to profit from market conditions while the claimant separately suffers a loss, that parallel change does not necessarily establish unjust enrichment. There must be a sufficient relationship between the benefit received and the value for which the claimant seeks restoration.
Why Is Retention Unjust?
This is usually the most important question. Mistake, failure of consideration, invalid transactions, benefits conferred under circumstances creating an expectation of payment, or other recognized grounds may make retention unjust. By contrast, a valid gift is an enrichment that the recipient is ordinarily entitled to keep.
The Role of Contract
A valid contract often controls the parties’ rights and can limit the use of unjust enrichment as an alternative theory. Courts generally should not use restitution to rewrite the allocation of benefits and risks that the parties already made in an enforceable agreement. Restitution becomes especially important when no enforceable contract governs the benefit or when the contract has been avoided or rescinded.
Remedy
The remedy typically focuses on restoring the benefit or its value rather than giving the claimant the profits expected from a bargain. That distinguishes restitution from expectation damages and keeps the doctrine centered on reversing unjust retention.
The most useful unjust-enrichment analysis therefore asks four questions: What was received? At whose expense? Why is retention unjust? And what restoration fairly corresponds to the enrichment?