PetroChina Company Limited (SEHK: 0857, SSE: 601857, NYSE: PTR) is a Chinese oil company and is the listed arm of state-owned China National Petroleum Corporation (CNPC), headquartered in Dongcheng District, Beijing. It is China's biggest oil producer, and was the world's most valuable company by market value as of September 28th 2010. Traded in Hong Kong and New York, the mainland enterprise announced its plans to issue stock in Shanghai in November 2007, and following its debut on the Shanghai index, its market value tripled, making PetroChina the first company to reach a trillion dollar market capitalization.
