The successful bidder will be notified in writing of the acceptance of his bid. Under construction contracts, this notice may accompany the contract papers which are forwarded for execution. To avoid error, or confusing the notice of award with a notice to proceed, the notice of award will be substantially in the following format:
Under supply contracts a written award mailed (or otherwise furnished) to the successful bidder either on Standard Form 26 or Standard Form 33, results in a binding contract without further action by either party.
Code of Federal Regulations
[26 FR 11732, Dec. 7, 1961]