AutoNation Inc., the largest chain of auto dealerships in the U.S., on Thursday reported a surge in fourth-quarter revenue as American consumers streamed back into showrooms and the U.S. economy strengthened.

The Ft. Lauderdale, Fla., company said its fourth-quarter income rose to $69.4 million, or 49 cents a share, from $67.3 million, or 45 cents a share, in the year-ago period. Excluding losses from discontinued operations, earnings were 51 cents a share, according to The Wall Street Journal. Analysts expected adjusted earnings of 48 cents a share, according to estimates compiled by Thomson Reuters.

Revenue, boosted by stronger sale of Detroit-brand and luxury vehicles, jumped 17 percent to $3.68 billion from $3.45 billion a year ago.

Operating profit in the quarter rose to $143.5 million from $134.6 million.

For the full year, AutoNation said 2011 revenue increased to $13.8 billion from $12.5 billion. Operating profit increased to $572 million from $496.6 million. The company reported earnings per share of $1.91 for 2011, compared to $1.43 in 2010.

AutoNation also said its board of directors has authorized an additional $250 million for repurchasing its own shares. It now has a total of $278 million for stock buybacks.

Between Jan. 1 and Jan. 25, AutoNation purchased 3.5 million of its own shares for $122 million, at an average price of $34.74.

In 2011, AutoNation repurchased a total of 17.1 million of its own shares for $583.4 million, at an average price of $34.14.

AutoNation shares were up nearly 1 percent, or 33 cents, at $36.67 in mid-day trading Thursday on the New York Stock Exchange.

AutoNation operates 258 new-car franchises in 15 states, mainly in southern and western states.