In Worlds Inc. v. Bungie Inc., the Fed. Cir. reversed and remanded the PTAB’s invalidation of three patents in IPRs.  The Board had rejected patentee's evidence as insufficient, that the IPRs were time bared based on an unnamed real-party-in-interest.  Using Atlanta Gas Light as a framework for analysis, which was agreed to by the parties, the Fed. Cir. objected to the Board’s “rebuttable presumption” of the accuracy of the IPR Petitioner’s identification of the real-party-in-interest in favor of acceptance of an initial identification until disputed by the patent owner.  Following the patent owner’s presentation of evidence of an unnamed real-party-in-interest, the Board was found to have erred in finding the patent owner's evidence unpersuasive, possibly improperly shifting the burden of persuasion to the patent owner.  The case was remanded to better develop a record whether the patent owner was estopped from contesting the real-part-in-interest issue based on their action in an earlier IPR, and if not estopped, reevaluate the merits of the real-party-in-interest issue.