On February 21, 2014, the Federal Circuit decided en banc in Lighting Ballast Control LLC v. Philips Electronics North America Corp. Appeal No. 12-1014, not to change its long-standing practice of reviewing all claim construction rulings de novo on appeal, overruling proponents supporting that giving more deference to lower courts would make patent litigation more predictable.  The issue sharply divided theen banc Court, but the majority in the 6-4 decision concluded that the current de novo review standard for all claim construction rulings has worked well since it was established in Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998) and that there was no reason to change it.  Under Cybor, claim construction was a matter of law that received de novo review on appeal without any deference to a district court’s ruling.  The majority held the criteria for departing from stare decisis and changing existing claim construction methodology or abandoning de novo review had not been met.  The Federal Circuit‘s en banc decision also applies to Commission decisions in Section 337 investigations. However, the decision is now ripe for potential review by the U.S. Supreme Court.