Oct 31 (Reuters) - Exxon Mobil Corp, the world's largest publicly traded oil company, on Thursday reported an 18 percent decrease in quarterly profit on weakness in its refining business.
Profit in the third quarter was $7.87 billion, or $1.79 per share, compared with $9.57 billion, or $2.09 per share, in the same period a year earlier.
"Weaker margins, mainly in refining, decreased earnings by $2.4 billion," Exxon said in a statement.
Analysts on average had expected a profit of $1.77 per share, according to Thomson Reuters I/B/E/S.
Oil and natural gas output in the quarter rose 1.5 percent from a year earlier, helped by the start-up of new projects and decreased maintenance, the Irving, Texas, company said.