Shares of World Fuel Services Corp have fallen after the company said crude oil sold by one of its units was being carried by railcars involved in the deadly train derailment in Lac-Megantic, Quebec, last weekend. World Fuel, formed in 1984, arranges buyers and sellers for oil and other fuels across the Western Hemisphere. It does not drill for oil or directly transport it, and most of its customers are involved in aviation, shipping and trucking. The company's profit comes by extracting margins from buying and selling of fuels. The company's annual revenue has jumped 110 percent since 2008, the start of the North American shale boom. The runaway oil tanker train derailed in Lac-Megantic, exploding in a deadly ball of flames and killing at least 13 people. The train was carrying crude from North Dakota to a refinery in Saint John, New Brunswick, owned by privately held Irving Oil. (Reuters)