Aetna (AET) released stronger-than-expected fourth-quarter results, issued bullish 2011 guidance and sharply boosted its dividend on Friday, sparking a 12% surge in its stock.

The Hartford-based health-care company said it earned $215.6 million, or 53 cents a share, compared with a profit of $165.9 million, or 38 cents a share, a year earlier. Excluding one-time items, it earned 63 cents a share, beating the Street by a penny.

Revenue dipped 2% to $8.54 billion.

Aetna said it sees 2011 operating earnings exceeding $3.68 a share, a slight increase from last year. Rivals such as Humana (HUM) and UnitedHealth (UNH) have warned profits may slip.

"I am confident that we are well-positioned with the right management team and long-term strategy to capitalize on the domestic and global opportunities in health care," CEO Mark Bertolini said in a statement.

Meanwhile, Aetna also hiked its quarterly dividend to 15 cents a share, well above its previous payout of just 4 cents a year.

Shareholders cheered the developments, sending Aetna's stock surging 12.2% to $37.33 ahead of Friday's open. The stock had already been up just over 9% in 2011.

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