PetroChina briefly became the world’s largest company by market capitalization on its Shanghai debut in 2007.
PetroChina shares surged when the company began trading on the Shanghai Stock Exchange on 5 November 2007. The opening-day rally temporarily pushed its implied market capitalization above that of ExxonMobil, making PetroChina the world’s most valuable publicly traded company by that measure.
The valuation was unusually short-lived. PetroChina’s shares fell sharply after the initial surge, and its market capitalization soon dropped well below the extraordinary debut-day level. The episode is often cited as an example of how a stock-market price can be distorted by speculative enthusiasm, limited available shares, and intense demand.
PetroChina is the listed subsidiary of China National Petroleum Corporation, one of China’s major state-owned energy groups. Its business includes oil and gas exploration, production, refining, and distribution. The company’s debut was separate from its earlier listing in Hong Kong and New York.