A somewhat overlooked U.S. Supreme Court decision from last month has breathed new life into claims that BP plc mismanaged employee stock ownership programs (ESOPs) that plummeted in value after the 2010 Deepwater Horizon oil spill.

In a decision issued on Tuesday, the U.S. Court of Appeals for the Fifth Circuit revived a class action alleging that BP breached fiduciary duties to ESOP participants by overinvesting in company stock. The Fifth Circuit based its decision on Fifth Third Bancorp v. Dudenhoeffer, a 9-0 Supreme Court decision from June 25 that gutted an important defense to investor class actions brought under the Employee Retirement Income Security Act (ERISA).