The Federal Reserve's little-known role housing the assets of other central banks comes with a unique benefit to the United States: It serves as a source of foreign intelligence for Washington. Senior officials from the U.S. Treasury and other government departments have turned to these otherwise confidential accounts several times a year to analyze the asset holdings of the central banks of Russia, China, Iraq, Turkey, Yemen, Libya and others, according to more than a dozen current and former senior Fed and Treasury officials. The U.S. central bank keeps a tight lid on information contained in these accounts. But according to the officials interviewed by Reuters, U.S. authorities regularly use a need to know" confidentiality exception in the Fed's service contracts with foreign central banks. Some 250 foreign central banks and governments keep $3.3 trillion of their assets at the Federal Reserve Bank of New York, about half of the world's official dollar reserves, using a service advertised in a 2015 slide presentation as "safe and confidential." Other major central banks and some commercial banks offer similar services. But only the Fed offers direct access to U.S. debt markets and to the world's reserve currency, the dollar. In all, the people interviewed by Reuters identified seven instances in the last 15 years in which the accounts gave U.S. authorities insights into the actions of foreign counterparts or market movements, at times leading to a specific U.S. response.