By The Associated Press

NEW YORK, N.Y. – AT&T Inc. is still the home of the iPhone. It activated 7.6 million of them in the latest quarter, accounting for one out of every five iPhones sold globally.

And AT&T remains heavily dependent on the iPhone to gain and keep customers, despite a vow by CEO Randall Stephenson a year ago to “very aggressively” market competing smartphones in 2011. That vow came in the wake of AT&T’s loss of an exclusive right to sell the iPhone in the U.S.

The iPhone accounted for about 80 percent of the smartphones AT&T activated in the fourth quarter of 2011, up from 70 percent just before Stephenson made his vow.

The figures are somewhat skewed because the fourth quarter of 2011 saw the launch of a new iPhone model, the iPhone 4S, whereas the fourth quarter of 2010 didn’t. Looking at annual sales instead, there’s a decline in the iPhone’s percentage of AT&T smartphones – to 69 percent last year, from 79 percent in 2010.

The Dallas-based company has also retained its position as the premier U.S. iPhone carrier, beating Verizon Wireless’ 4.3 million iPhone activations handily.

AT&T’s iPhone dependency comes at a heavy cost. The phone is more expensive than many other smartphones, and AT&T needs to subsidize each iPhone with hundreds of dollars to put it in customers’ hands for as little as $1.

That, together with massive charges for adjustments in the value of the company’s pension plans, the breakup of a deal to buy T-Mobile USA and a writedown of the value of its phone-directory business, forced AT&T to report a massive loss on Thursday of $6.68 billion, or $1.12 per share, for the fourth quarter.

It was the first quarterly loss for AT&T in three years. An adjustment of pension-plan obligations was also the main culprit behind the previous loss, in the fourth quarter of 2008.

AT&T took a charge of $4.2 billion for the compensation it’s paying T-Mobile USA. When AT&T made the $39 billion bid in March, it promised T-Mobile cash and wireless licenses if the deal fell through. The deal was squelched by federal regulators, who saw reason to believe that the No. 2 wireless carrier buying No. 4 would reduce competition.

On Thursday, Stephenson said the company’s Plan B consists of trying to buy more wireless spectrum in smaller deals, selling low-performing units and instituting a share-buyback program.

AT&T said it has board authorization to buy back 300 million shares, worth about $9 billion, and will start doing so immediately.

Excluding charges, net income was 42 cents per share in the latest quarter, a penny shy of Wall Street expectations, according to a survey by FactSet.

The loss compares with net income of $1.09 billion, or 18 cents per share, in the same period a year earlier.

Revenue rose 3.6 percent to $32.5 billion, helped by the smartphone sales. Analysts were expecting revenue of $31.99 billion, on average.

After stripping out the jump in smartphone sales, which constitute an immediate loss for the company, revenue grew 0.6 percent from last year. Wireless service fees are growing slower than before, barely making up for the decline of AT&T’s traditional-phone business.

AT&T said it expects earnings per share to grow by a mid-single-digit percentage in 2012, a bit lower than analysts had expected.

In afternoon trading Thursday, shares of AT&T Inc. fell 68 cents, or 2.3 percent, to $29.53.

Most of the iPhone activations were upgrades for people who were already AT&T subscribers. The carrier gained a net 717,000 subscribers on contract plans in the quarter. That was the best result all year, but didn’t match Verizon’s 1.2 million. AT&T has been lagging Verizon in this important measure for more than a year.

For all of 2011, AT&T earned $3.9 billion, or 66 cents per share, on $126.7 billion in revenue. That compares with $19.9 billion, or $3.35 per share, on $124.3 billion in revenue in 2010.

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