Before World War 2, the United States and Germany had extensive trade relations. Germany was the United States' fourth largest trading partner and purchased raw materials, agricultural products, and finished goods from the United States. In return, the United States purchased machinery, chemicals, and other manufactured goods from Germany.
After the war began in 1939, the United States and Germany continued to trade, although the volume of trade declined significantly. The United States government imposed restrictions on trade with Germany in order to prevent the country from acquiring materials and supplies that could be used for military purposes. However, the United States continued to export some goods to Germany, including food and medical supplies.
In 1941, the United States declared war on Germany after the German attack on Pearl Harbor. This ended all trade between the two countries.