Exxon Mobil earnings: Down today, up tomorrow, but after that ... who knows?

Exxon Mobil (XOM) is the beast of the global energy industry. It ranks No.1 in market cap among all companies traded on U.S. exchanges with a market value of $355 billion That is $125 billion ahead of Chinese oil giant PetroChina (PTR) and more than double the market cap of the next-largest U.S.-based energy company, Chevron (CVX).

The market started to show some concern about Exxon's earnings over a year ago, when the stock began its descent from nearly $95 to the $73 where it trades today. Most large global oil companies have turned in only modest earnings for the last quarter because crude prices traded around $65 a barrel during that period, less than half their July 2008 peak. Earlier this week, BP (BP) posted earnings for the third quarter that were off 34 percent from last year. It said the major reason for the dip was relatively low oil and gas prices.