How did WWI contribute to the boom in America?

During the first two and a half years of combat, the United States was a neutral party and the economic boom came primarily from exports. The total value of U. S. exports grew from $2.4 billion in 1913 to $6.2 billion in 1917

The First World War had been good for American business. Factory production had risen sharply to meet the needs of the war. America had been able to capture markets that used to buy from Europe. Once the war was over these countries continued to buy American goods.