NEW YORK (Bloomberg) — Exxon Mobil Corp., the world's biggest company, posted its largest third-quarter profit increase in six years as rising worldwide energy demand lifted commodity prices.

Third-quarter net income rose 55 percent to $7.35 billion, or $1.44 a share, from $4.73 billion, or 98 cents, a year earlier, Irving, Texas-based Exxon said in a statement yesterday. Per-share profit was five cents more than the average of 14 analysts' estimates compiled by Bloomberg.

Motorists, airlines and railroads are burning crude-based fuels at a rate of one supertanker load every 33 minutes this year, a 2.2 percent increase from 2009, according to Barclays Capital. Exxon boosted production by more than one-fifth amid a 12 percent jump in US oil futures.

"Exxon already was producing more oil and gas than any of the other public companies so for them to increase output and by such a large margin is a good thing," said Douglas Ober, whose $682 million under management at Petroleum & Resources Corp. in Baltimore includes Exxon stock. "This probably took a lot of people by surprise."

The increase in net income was the largest for a third quarter, excluding one-time gains, since 2004. Exxon rose 74 cents, or 1.1 percent, to $66.41 at 9:37 a.m. in New York Stock Exchange composite trading. The shares, which before yesterday had declined 3.7 percent this year, have nine buy ratings from analysts, 12 holds and one sell.

Chief executive officer Rex Tillerson is spending almost $77 million a day this year to increase oil, natural-gas and diesel production. Exxon is focusing investments in new wells in Canada, California and Texas after a bid to acquire offshore discoveries in Ghana collapsed and a New Zealand prospect was abandoned as too risky.

Exxon increased production 21 percent to the equivalent of 4.45 million barrels a day, the most since the first three months of 2006. The output increase was driven in part by Exxon's purchase of natural-gas producer XTO Energy, its largest acquisition since the 1999 merger with Mobil Corp.

Sales rose 16 percent to $95.3 billion and profit from oil and gas wells climbed 36 percent to $5.47 billion. Profit from company's refineries more than tripled to $1.16 billion as the margin between the cost of crude and the price of gasoline and diesel widened. Exxon's chemicals business posted a 40 percent profit increase to $1.23 billion.

The company said it purchased $3.3 billion of its own shares during the quarter and plans to make another $5 billion in buybacks before the end of the year.

Exxon's cash flow from operations and asset sales jumped 54 percent from a year earlier to $13.9 billion, according to a public filing yesterday.

The company has exceeded the average per-share profit estimates of analysts in three of the past four quarters, according to data compiled by Bloomberg.

"Global oil demand implications have continued to surprise to the upside," a team of Barclays analysts including Costanza Jacazio and Amrita Sen said in an October 20 note to clients. Oil futures in New York averaged $76.21 a barrel during the third quarter.

Rising oil and gas prices spurred energy producers to complete 123 US wells a day during the July-to-September period, a 45 percent increase from a year earlier, according to the American Petroleum Institute.