HEILONGJIANG PROVINCE, CHINA - July 14: A CNPC "nodding donkey" oil pump pumps oil in the middle of a residential complex on July 14, 2006 in Daqing, Heilongjiang province, China. China National Petroleum Corp. (CNPC) is the parent company of PetroChina. PetroChina went public on the Shanghai Stock Exchange Monday, Nov. 5, and the shares nearly tripled the same day. At US$1.005 trillion market capital, PetroChina is now the only trillion-dollar company in the world, twice the value of its US peer Exxon Mobil. (Photo by Servais Mont/Getty Images)