Teekay Tankers Ltd is a provider of marine services to the international oil and natural gas industries and an operator of medium-sized oil tankers. The company operates in two segments: Tankers, which consists of the operation of all of the company's tankers (including the operations from those tankers employed on full service lightering contracts), and the company's U.S. based ship-to-ship support service operations (including its lightering support services provided as part of full service lightering operations); and Marine Services, which consists of operational and maintenance marine services provided to the Australian government, Australian energy companies and other third parties. The company generates the majority of its revenue from the Tankers segment.