PetroChina briefly became the world’s most valuable public company in 2007 after its shares surged in Shanghai.
PetroChina’s Shanghai-listed shares jumped on their first trading day in November 2007, giving the company a market capitalization above $1 trillion on a temporary basis. The valuation made it appear larger than established global leaders such as ExxonMobil, although the price rapidly fell afterward.
PetroChina is the publicly traded subsidiary of China National Petroleum Corporation, a state-owned energy group. Its activities include exploration, production, refining, chemicals, and petroleum marketing. The company’s Hong Kong and Shanghai listings represent the same underlying business but can trade at different prices.
The episode illustrates why “most valuable company” claims need a date and a market definition. A brief intraday or first-day valuation is not the same as maintaining the highest market capitalization over a sustained period.