PetroChina made the first stock-market debut valued above US$1 trillion when its Shanghai shares began trading on 5 November 2007. The opening surge briefly made it the world's largest company by market capitalization, despite only a minority of shares being publicly traded.
PetroChina is the listed arm of China National Petroleum Corporation, China's state-owned oil and gas group. Enthusiasm for Chinese equities and high global oil prices helped drive extraordinary demand on the first trading day.
The valuation quickly fell from its debut peak, demonstrating how an opening price can differ dramatically from a long-term market value. Saudi Aramco later set the record for the largest IPO by money raised, but PetroChina retains the historic debut-valuation distinction.