An inventor loses the right to a U.S. patent if the invention is sold or offered for sale in the U.S. more than one year prior to his/her U.S. filing date [35 U.S.C 102(b)]. This usually occurs when the inventor or someone else sells or offers for sale the invention in the U.S. over a year before the inventor files in the U.S. This sort of delay is fatal and results in a statutory bar to patentability.
It is important to note that the act (offering to sell or sale of the invention) can be performed by anyone. It must, however, occur in the U.S (or in its possessions or territories) and before a specific date. That date is one year before the earliest effective filing date of a provisional or nonprovisional (regular) U.S. patent application or an international (PCT) application that designates the U.S. As far as application of this rule is concerned, it matters not what the date of invention is or that the inventor(s) can claim priority of invention based on the filing date of a non-U.S. (national or regional) patent application. Only the U.S. filing date (which can be the same as the PCT filing date) is considered. Neither does it matter whether the offer to sell or sale is public or secret. Sales or offers to sell that occur in other countries, e.g., in World Trade Organization (WTO) or North American Free Trade Agreement (NAFTA) member countries, does not invoke the bar.
Merely preparing or being prepared to offer the invention for sale is not enough, a definite offer to sell or sale must occur. However, an offer for sale does not have to be consumated, i.e., an actual sale does not have to occur. The invention does not have to be on hand when the offer is made or sale occurs and an actual delivery of the invention does not have to occur. The invention being offered for sale must have been reduced to a reality that "is beyond the stage of experimentation" but reduction to practice need not have occurred. Offering to assign or license an invention, a patent application or a patent is not an offer to sell the invention itself and does not invoke the bar.
In deciding whether an offer for sale or sale has occurred, the "totality of the circumstances" must be considered. The focus is generally on whether the purpose of the activity was commercial or experimental, whether the activity makes the invention available to the public and whether there is an agreement of confidentiality between the parties. Court decisions often consider the policies underlying the bar: discouraging removal from the public domain inventions that, at one time, were freely available, promoting the prompt disclosure of inventions, allowing inventors a reasonable amount of time to test the waters to determine the commercial potential of their inventions and preventing inventors from extending the patent monopoly. Patent Partner explains the experimental exception to this rule in another evaluation element.