We continue to get guidance as to when a party can file a request for an inter partes review of a patent. As I mentioned last Fall, under 35 U.S.C. § 315(b), a petitioner has 1 year from the date that it is “served with a complaint alleging infringement” to file a request for inter partes review. Last week, the U.S. Patent and Trademark Office (“Board”) clarified that the filing of an arbitration claim does not start this 1 year clock. Based on a 2009 arbitration, Tessera, Inc. moved to terminate an inter partes review initiated by Amkor Technology, Inc. for being outside the 1 year window. Thus, the question became whether “served with a complaint alleging infringement” included being served with an arbitration counterclaim of infringement. The Board noted that arbitration is not “litigation,” but rather an alternative dispute resolution procedure. Simply stated, “served with a complaint alleging infringement” only refers to disputes in District Court versus any forum for adjudicating infringement as Tessera had argued. We now know that complaints and counterclaims alleging infringement (even if dismissed with prejudice) are the two clear-cut ways to start the clock running with regard to the filing of requests for inter partes reviews.