William Ludwig Ullmann (August 14, 1908 – February 3, 1993) was an American Treasury Department official accused of spying for the Soviet Union.
In 1939 Ulmann was recommended by his superior C. B. Baldwin to Harry Dexter White and was hired at the Division of Monetary Research in the United States Department of the Treasury.
He was "chief photographer of stolen government documents for the Silvermaster espionage ring" while a Major in the Material and Services Division of the Army Air Corps.
He provided the Soviets with a considerable volume of almost every conceivable type of information relating to the United States Army Air Force's part in World War II.
Kathryn S. Olmsted, the author of Red Spy Queen (2002), points out: "Every two weeks, Elizabeth would travel to Washington to pick up documents from the Silvermasters, collect their Party dues, and deliver Communist literature.