Revisiting the On-Sale Bar after Pfaff

44 Pages Posted: 29 Jan 2005


The on-sale bar allows inventors a grace period to judge the worth of their ideas through limited commercialization. The Supreme Court set forth a test for triggering the bar in a decision five years ago, Pfaff v. Wells Electronics, but the test has caused excessive litigation. The test's first prong makes formal contractual distinctions having little to do with the way inventors do business, hurting innocent inventors while giving wilier ones a ready loophole. The second asks whether a sold invention was ready for patenting - at best causing immature ideas to be patented, at worst asking an unknowable question. In response this Article proposes a new, more concrete, on-sale bar test, starting the grace period only when an invention is built and delivered. It limits pre-filing commercialization by the inventor and reduces the possibility that the public will come to rely on the invention being in the public domain. It also gives inventors a better opportunity to judge the worth of their invention while still ensuring that they file promptly with the patent office.

An early version of this article was printed in the Albany Law Journal of Science and Technology.

Keywords: On-sale, bar, sale bar, Pfaff, patent, ready for patenting, reduction to practice, reduced to practice, practice, sold, contractual, supreme court, wells electronics

JEL Classification: K12, K3

Suggested Citation

Lindholm, Stephen Bruce, Revisiting the On-Sale Bar after Pfaff. Available at SSRN:

Stephen Bruce Lindholm (Contact Author)

Stanford Law School ( email )

559 Nathan Abbott Way
Stanford, CA 94305-8610
United States

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