Panel: Judges Dyk, Clevenger, and Hughes, with Judge Hughes writing the opinion and Judge Dyk dissenting. You should read this case if: You’re interested in issue preclusion or have one of the 10 remaining inter partes reexamination cases Last week a divided Court took a look at issue preclusion in administrative proceedings, and that definitely caught our eye. The appeal involves inter partes reexaminations—so if you haven’t had one, you aren’t likely to since they began their slow sunset after Congress passed the AIA and replaced them with inter partes reviews. In this reexamination, the Board found the patent owner’s claims would have been obvious, ruling against the patent owner on whether certain prior art references were incompatible and on motivation. The details don’t really matter for our purposes. What does matter is that in another, earlier (and now final) reexamination involving a different but related patent and the same parties, the Board reached the opposite conclusion on those two issues. So patent owner took an appeal in the later case, arguing that issue preclusion (also known as collateral estoppel) precludes relitigation of the issues that the patent owner won in the earlier case but lost in the later one. Not to bury the lede: the patent owner won.