Stock in Denmark's biggest bank Danske Bank plunged more than 10 percent Thursday after announcing a rights issue to pay back a loan from Denmark taken out during the financial crisis.

Danske Bank said in a statement it planned to raise approximately 20 billion Danish kroner (2.68 billion euros, $3.66 billion) through a rights issue to be launched in April at the latest, explaining it had borrowed a total of 26 billion kroner from the state in 2009.

The announcement sent shares plunging: at 1130 GMT they were down 10.53 percent to 125.70 kroner on a Copenhagen stock exchange down 1.55 percent.

The rights issue came as the group announced a net profit for 2010 up 113 percent to 3.66 billion kroner from 1.71 billion a year earlier. Its pre-tax profit leaped 36 percent to 6.45 billion.

"We consider the result acceptable given the market conditions. Still, it is far below the level of earnings that a bank of our size should deliver to its shareholders," the bank said.

The company's earnings also missed the expectations of analysts surveyed by SME Direkt, who forecasted a net profit of 4.26 billion and pre-tax profit of 7.64 billion.

The bank's total income, including its insurance business, plunged 22 percent to 46.27 billion kroner from 59.34 billion in 2009.

"We are on the right track," chief executive Peter Straarup said.

"We expect our results to improve further in 2011 and to see a continued decline in impairment charges," he added.

Impairment charges in 2010 were 13.81 billion, down from 25.67 billion in 2009. Danske Bank's subsidiaries in Ireland and Northern Ireland were the only ones still affected by high impairment charges, the bank said.

Danske Bank, the second-biggest Nordic banking group after Sweden's Nordea, has branches in Finland, Norway, Sweden, Ireland, Britain, Russia, Germany, Poland, Luxembourg and the Baltic countries.