Acceptance by Promise

Bilateral contracts are accepted by a return promise or beginning performance.

Representative cases

• Stortroen v. Beneficial Finance Co. 736 P.2d 391 · Supreme Court of Colorado
• United Concrete Pipe Corp. v. Spin-Line Co. 430 S.W.2d 360 · Texas Supreme Court
• Valdez Fisheries Development Ass'n v. Alyeska Pipeline Service Co. 45 P.3d 657 · Alaska Supreme Court

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.
• Mailbox RuleAcceptance is effective upon dispatch unless otherwise specified.

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