Introduction The authors have recently proposed alternative analyses for the discretionary denial of IPR and PGR petitions involved in parallel district court litigation, as well as for the discretionary denial of serial petitions filed before the Patent Trial and Appeal Board (“PTAB”). The PTAB is also currently at a crossroads with yet a third similar but distinct issue—the discretionary denial of parallel petitions filed before the PTAB. “Serial petitions” refer to multiple successive petitions challenging a particular patent that are filed by the same or different petitioners, ...