On March 15, five federal agencies—the FDIC, FHFA, Federal Reserve Board, OCC, and Farm Credit Administration (collectively, the “Agencies”)—adopted an interim final rule amending the agencies’ regulations that require swap dealers and security-based swap dealers under the Agencies’ respective jurisdictions to exchange margin with their counterparties for swaps that are not centrally cleared (Swap Margins Rule). The interim final rule seeks to address the situation where the United Kingdom withdraws from the European Union without a negotiated agreement and entities located in the U.K. transfer existing swap portfolios that face counterparties located in the E.U. over to affiliates located in the U.S. or the E.U. Specifically, the interim final rule provides that certain swaps under this situation will not lose their “legacy” status—will not trigger the application of the Swap Margin Rule—if carried out in accordance with the conditions of the rule. The interim final rule is effective immediately and the Agencies are accepting comments for 30 days after publication in the Federal Register.