Butterfield Bank shares surged 4.9 percent on the Bermuda Stock Exchange after a week of above average trading activity following the bank’s release of annual results.In the six trading days since Butterfield announced a loss of $207.6 million for 2010, more than 412,000 shares have traded in the bank.That is more than the sum of all the Butterfield shares traded over the two-and-a-half months before the results release after the close of trading on February 22.Most of the losses detailed in the bank’s financial statements related to realised losses from the selling off of troubled assets, as the bank cleaned up its balance sheet.Butterfield CEO told The Royal Gazette that the bank had “cleaned house” and put its troubles of the past three years behind it.Yesterday, Butterfield’s common shares closed on $1.29, up six cents on the day, after just over 15,000 shares changed hands.