PetroChina became the world’s most valuable publicly traded company in 2007 after briefly overtaking ExxonMobil.
The shift occurred after PetroChina’s Shanghai listing generated extraordinary demand and sent its market capitalization above that of ExxonMobil. Because market capitalization depends on share prices, the ranking changed quickly and did not mean PetroChina had more revenue, production, or assets than ExxonMobil.
PetroChina is the listed arm of China National Petroleum Corporation and operates across oil and gas exploration, production, refining, and sales. Its debut coincided with strong investor optimism about China’s economy and rapidly increasing energy demand.
The episode is a useful reminder that market-cap rankings can differ depending on the date, exchange prices, share classes, and whether analysts count all listed and unlisted equity. It also helps explain why historical “largest company” claims should always include a time reference.