- Associated Press - Tuesday, August 9, 2011

NEW YORK — Apple briefly surpassed Exxon Mobil as the most valuable company in the U.S. Tuesday afternoon before settling back slightly lower.

But the two are now so close that the change of guard is likely to happen soon.

Apple Inc.’s stock gained 5.9 percent to $374.01 on Tuesday, bringing the iPhone and iPad maker’s market capitalization to about $347 billion when the market closed.

Exxon Mobil Corp. shares, meanwhile, closed up 2.1 percent at 71.64. That gives the oil company a market cap of $348 billion as of the market’s close.

Other big-name corporations, such as Wal-Mart Stores Inc. and General Electric Co., don’t even come close. Apple overtook Microsoft, the previous No. 2, just last year.

Exxon Mobil, which set a record in 2008 for the highest quarterly earnings by any company, has limited growth prospects. Its growth is driven by oil prices and discovering new oil.

By contrast, Apple has been on a roll with the soaring popularity of its iPad tablet computer and strong sales of the iPhone. Apple’s growth is limited only by innovation. Investors expect it to grow as long as it keeps making products that people want. So investors are betting on Apple’s stock even though it currently makes less money than Exxon.

In its latest quarterly report, Apple said stronger iPhone and iPad sales helped more than double its net income to $7.31 billion and grow revenue by 82 percent to $28.6 billion.

Exxon Mobil, meanwhile, posted a 41 percent increase in its second-quarter earnings to $10.68 billion, the largest since it set a record of $14.8 billion in the third quarter of 2008. Its revenue grew 36 percent to $125.5 billion.

Apple, which is based in Cupertino, Calif., has a higher price-to-earnings ratio than Exxon Mobil, but not by much. They are both lower than that of the average of the S&P 500 index.

International companies that vie for the most valuable spot include PetroChina Co., the publicly traded unit of China’s biggest oil and gas company, and Petrobras, Brazil’s state-controlled energy company.

In the U.S., Exxon Mobil and General Electric had been trading off the No. 1 and No. 2 spots until Microsoft Corp. surpassed them both in early 1999, at the height of the dot-com boom. By 2000, though, GE was No. 1 once again. According to data from FactSet, the three were close over the next five years, though Apple was ascending quickly.

Exxon Mobil, which is based in Irving, Texas, took the top spot in 2005 and has remained there until Apple surpassed it briefly Tuesday.

Apple surpassed Microsoft in market cap last year.