Companies that improperly mark their products with inapplicable or expired patent numbers are exposed to greater financial liability than ever before. On December 28, 2009, the U.S. Court of Appeals for the Federal Circuit held in Forest Group, Inc. v. Bon Tool Company, 590 F.3d 1295 (Fed. Cir. 2009), that a company can be liable for a fine of up to $500 per article (i.e., per unit) for false patent marking. Relying on the plain statutory language, congressional intent, and policy considerations, the court overruled decades of legal precedents that previously limited the penalty for such offense.

Potential liability under the false marking statute can arise under a variety of scenarios. For example, a company could face liability when it marks a product with a patent number (“Patented U.S. X,XXX,XXX”) knowing that such patent either does not exist or does not cover the product. Another scenario for potential liability arises when an article is marked with a relevant patent number, but the patent in fact has expired. A false marking claim also could be made when the article is marked with a “laundry list” of patent numbers, but not all are relevant or actually cover the article.