PetroChina briefly became the world’s most valuable company by market capitalization in July 2010.
The Chinese oil and gas producer reached the top of global market-cap rankings during a period when energy prices and investor interest in China’s expanding economy strongly influenced valuations. Its position was temporary because rankings change with share prices.
PetroChina is the listed arm of China National Petroleum Corporation, one of China’s major state-owned energy groups. The company operates across exploration, production, refining, marketing, and natural gas.
Market-cap comparisons can also be affected by which shares are counted, including publicly traded shares and government-held stock. This is why historical claims about the “most valuable company” should be tied to a specific date and calculation method rather than treated as permanent facts.