For businesses selling products through Amazon, a patent infringement notice can quickly become a significant commercial problem. Amazon’s Patent Evaluation Express (APEX) program allows U.S. utility patent owners, or their registered agents, to seek a neutral evaluation of an alleged infringement claim involving products sold on Amazon. An APEX notice can put an established product listing at risk, potentially disrupting sales, affecting marketplace visibility, and creating complications for inventory already manufactured or held in fulfillment centers. Sellers that have not considered these risks before receiving a notice may find themselves making important business and legal decisions under significant time pressure.