NEW YORK >> Apple briefly surpassed Exxon Mobil today as the nation’s most valuable company.

The iPhone and iPad maker had the lead for much of the afternoon before its stock closed just behind Exxon’s. The two companies are so close that Apple is likely to keep the top spot soon.

Apple Inc.’s stock gained 5.9 percent to $374.01 today, bringing its market capitalization to about $347 billion.

Exxon Mobil Corp.’s stock, meanwhile, closed up 2.1 percent at $71.64. That gives the oil company a market cap of $348 billion. Its stock was down earlier in the day, allowing Apple to take the lead.

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

Does this mean people need iPads more than oil?

“Exxon obviously sells a product that people need. Apple sells a product that people want,” said Brian Marshall, an analyst with Gleacher & Co. who follows Apple. 

Exxon, which set a record in 2008 for the highest quarterly earnings by any company, has limited growth prospects, which are driven by oil prices and discovering new oil. It’s growing, but not as quickly as Apple, which is charging ahead at the pace of a startup, Marshall says, even though the company is 35 years old. 

Apple, which is based in Cupertino, Calif., has been on a roll with the soaring popularity of its iPad tablet computer and strong sales of the iPhone. Its 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.

International companies that vie for the most valuable spot in the world 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 and General Electric had been trading off the No. 1 and No. 2 spots until Microsoft 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, for now, remained there today.

Marshall believes Apple may pass yet another milestone next year, when it’s likely to surpass Hewlett-Packard Co. as the world’s largest technology company by revenue. In the quarter that ended in April, HP reported $31.6 billion in revenue, compared with Apple’s $28.6 billion in the just-ended period. HP reports results for the May-July period next week.