People stand before an electronic board displaying the characters for "PetroChina" at the Shanghai Stock Exchange in Lujiazui Financial Area November 5, 2007. Shares in PetroChina, which raised $9 billion in the world's biggest initial public offer this year, nearly tripled in their market debut and far exceeded analysts' forecast, buoyed by the company's position in the world's second-biggest energy market. (Agencies)

SHANGHAI - Shares in PetroChina Company Limited, China's largest oil and gas producer, opened Monday at 48.6 yuan on their first day of trade in the mainland A share market, up 191 percent from their IPO price of 16.7 yuan.

The price made PetroChina the world's largest listed company by market capitalization. The previous biggest, Exxon Mobil, was valued at 487.7 billion US dollars according to last Friday's share price.

PetroChina raised 66.8 billion yuan ($8.9 billion) in Shanghai by selling 4 billion A shares, or 2.18 percent of its expanded share capital, in the world's biggest initial public offer (IPO) this year.

PetroChina is already listed in Hong Kong and the United States. Its Hong Kong share price was 19.60 HK dollars last Friday.