CNOOC Limited, an investment holding company, explores for, develops, produces, and sells oil and natural gas. It produces offshore crude oil and natural gas. Its core operation areas are Bohai, Western South China Sea, Eastern South China Sea, and East China Sea in offshore China. The company also has oil and gas assets in Asia, Africa, North America, South America, Oceania, and Europe. As of December 31, 2012, it owned net proved reserves of approximately 3.49 billion barrels-of-oil equivalent. CNOOC Limited also provides bond issuance services. The company is based in Hong Kong, Hong Kong, and is considered a Red Chip company due to its listing on the Hong Kong Stock Exchange. CNOOC Limited is a subsidiary of China National Offshore Oil Corporation.