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2. AT&T
2. AT&T
Fortune 500 rank: 12
2010 profit: $19.9 billion

Even before its proposed mega-deal with T-Mobile this year, AT&T was on a roll. In 2010 the iPhone sold like gangbusters; its network quality saw some improvements; and wireless data revenues jumped by almost 30%--the highest among the industry's giants.

Profits rocketed nearly 60% during the year, helped by a few notable divestitures, to make AT&T the second most profitable in the Fortune 500. How long it holds that ranking depends on how attractive AT&T remains to consumers after losing exclusive rights to the iPhone to Verizon, and whether it can bring even more meaningful boosts to its network .

NEXT: 3. Chevron
Last updated May 10 2011: 8:38 AM ET
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