A patentee who makes or sells a patented article must mark his articles or notify infringers of his patent in order to recover damages.
Section 287(a) provides:
Patentees, and persons making, offering for sale, or selling within the United States any patented article for or under them, or importing any patented article into the United States, may give notice to the public that the same is patented, either by fixing thereon the word "patent" or the abbreviation "pat.", together with the number of the patent . . . . In the event of failure so to mark, no damages shall be recovered by the patentee in any action for infringement, except on proof that the infringer was notified of the infringement and continued to infringe thereafter, in which event damages may be recovered only for infringement occurring after such notice [emphasis added].
In Arctic Cat Inc. v. Bombardier Rec. Prods., 2017 U.S. App. LEXIS 24700, the Federal Circuit found legal error in the lower court's marking analysis and reiterated that "the burden of proving compliance with marking is and at all times remains on the patentee." In this case, BRP identified fourteen unmarked Honda PWCs, which it argued fell within the patent claims, and it was the patentee's burden to establish compliance with the marking statute—that these products did not fall within the patent claims.
The Federal Circuit explained that there is an initial burden, "a low bar," by the alleged infringer to articulate products it believes to be unmarked "patented articles." The Court noted that this is merely a burden of production, and not one of proof or persuasion. Once the alleged infringer meets this burden of production, however, the patentee bears the burden to prove the products identified do not practice the patented invention. The Federal Circuit would not comment on what minimum showing is needed to meet this initial burden of production, but held that BRP satisfied it in this case by identifying certain products that it believed were unmarked.
Thus, once this burden of production was met, it was Arctic Cat's burden to prove those products—once identified—do not practice the patent-at-issue. The Court clarified that "[t]he alleged infringer need not produce claim charts to meet its initial burden of identifying products. It is the patentee who bears the burden of proving that it satisfied the marking requirements and thus the patentee who would have to prove that the unmarked products identified by the infringer do not fall within the patent claims." In this case, the Federal Circuit held that the district court erred in placing this burden upon BRP and vacated and remanded as to the marking issue.
This case is yet another example of why it is important for patentees to not only mark their products, but to maintain complete and accurate listings of (1) their patent portfolio, (2) the products being sold, and (3) which products are covered by which patents, and which products require updated markings to reflect newly-issued patents.