Firm offer

[1] As a general rule, all offers are revocable at any time prior to acceptance, even those offers that purport to be irrevocable on their face.

In the United States, an exception is the merchant firm offer rule set out in Uniform Commercial Code - § 2-205, which states that an offer is firm and irrevocable if it is an offer to buy or sell goods made by a merchant and it is in writing and signed by the offeror.

Any such term of assurance in a form supplied by the offeree must be separately signed by the offeror.

However, even when the period of irrevocability expires, the offer may still remain open until revoked or rejected according to the general rules regarding termination of an offer.

If the offeree rejects, fails to accept the terms of the offer, fixed or otherwise, or makes a counter-offer, then the original offer is terminated.