PetroChina became the world’s most valuable publicly traded company when its shares began trading in Shanghai in 2007.
PetroChina’s A-share debut on the Shanghai Stock Exchange in November 2007 briefly gave it a market capitalization above $1 trillion. That valuation made PetroChina the world’s most valuable listed company at the time, although its share price soon fell and the ranking did not last.
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, marketing, and related services. The company’s enormous debut valuation was shaped by both its scale and the enthusiasm surrounding China’s stock market.
The episode is a useful reminder that market-capitalization rankings can change quickly. A company may become the most valuable briefly because of a new listing or a sharp price move, without permanently retaining that position.