Promissory Estoppel

Promissory estoppel enforces promises that foreseeably induce reliance and where injustice can be avoided only by enforcement.

Representative cases

• Thomerson v. DeVito Supreme Court of South Carolina
• Cottonwood Improvement Dist. v. Qwest Corp. 2013 UT App 24 · Court of Appeals of Utah
• Zambetti v. Cheeley Investments, L.P. 343 Ga. App. 637 · Court of Appeals of Georgia

Related Formation rules

• Contract DefinedA contract is a legally enforceable promise formed by mutual assent and consideration.
• Offer RequirementsAn offer is a manifestation of intent to be bound with definite terms communicated to an identifiable offeree.
• Termination of OfferOffers terminate by revocation, rejection, lapse, death, or destruction of subject matter.
• Option ContractsAn option is irrevocable when supported by consideration for a promise to keep the offer open.
• Firm Offers (UCC)A merchant’s signed writing assuring it will remain open is irrevocable for the period stated, up to 3 months.
• Acceptance: Mirror RuleUnder common law, acceptance must mirror the offer; additional or different terms are counteroffers.
• Acceptance by PerformanceUnilateral contracts are accepted only by complete performance.
• Acceptance by PromiseBilateral contracts are accepted by a return promise or beginning performance.

Part of Contracts on Core Legal Rules — foundational MBE-tested principles with primary-source citations.