Horizon Oil Limited is an Australia-based company. The Company is engaged in exploration, development and production of petroleum. It operates in one business segment, namely exploration, development and production of hydrocarbons. The Company operates mainly in New Zealand, China, Papua New Guinea, United States and Thailand. The Company’s subsidiaries include Horizon Oil International Limited, Horizon Oil (New Zealand) Limited, Horizon Oil (G1) Limited, Horizon Oil (G3) Limited, Horizon Oil (USA) Inc. and Horizon Oil (Siam) Limited. On February 13, 2009, the Company divested Thai petroleum concessions.