PetroChina briefly became the world’s most valuable company by market capitalization in 2007, surpassing ExxonMobil.
The milestone followed PetroChina’s major listing on the Shanghai Stock Exchange. On its first trading day, the company’s shares surged, producing an exceptionally high market valuation. The ranking was short-lived because the price fell sharply after the initial excitement.
PetroChina is the publicly traded arm of China National Petroleum Corporation, one of China’s major state-owned energy groups. Its businesses include oil and gas exploration, production, refining, transportation, and sales.
The episode illustrates why market capitalization rankings can be volatile, especially around an initial public offering. A company can briefly become the most valuable listed business without having the largest revenue, reserves, or long-term economic value. Temporary share-price spikes can dramatically change the ranking.