Most white-collar lawyers practicing today are familiar with the seminal 1981 decision in Upjohn Co. v. United States and its explanations of how privilege works in investigations, but several lower court decisions in recent years have muddied the waters. In October 2025, the U.S. Court of Appeals for the Sixth Circuit issued a decision in In re: FirstEnergy Corporation (Decision) clarifying the applicability of the attorney-client privilege and work product doctrine in corporate investigations, letting many practitioners breathe a sigh of relief. This first article in a two-part series analyzes the Decision and offers insights on its implications for future corporate investigations. The second article will lay out current best practices for preserving privilege in internal investigations in light of the Decision. See “Loose Lips Sink Ships: Maintaining Confidentiality in Investigations” (Nov. 20, 2024).