The Depository Institutions Deregulation and Monetary Control Act (MCA) has shaped how state-chartered financial institutions apply and export favorable interest rates across state lines for more than four decades. In 2023, Colorado became the first state in decades to exercise its right to opt out of certain provisions of the law. Now, a closely watched legal challenge is testing just how far that decision reaches. Polsinelli shareholder and former OCC enforcement lawyer Travis Nelson examines what is currently at stake in the Colorado litigation, why its outcome could reshape the competitive landscape for state and national charters, and what could come next as the case moves forward.