Shares of Butterfield Bank surged 5.5 per cent in Bermuda Stock Exchange trading.The bank gained $1.50 to close on $29 on the trading of 2,473 shares.Butterfield’s US-listed shares also had a positive day, gaining $1.18, or 4.4 per cent, to close on $29.67 on the New York Stock Exchange.Butterfield’s rise was enough to propel The Royal Gazette/BSX Index higher by 67.46 points, or 3.43 per cent, to 2,035.45.For the week, the index was down 2.11 per cent, mainly as a result of the 2.8 per cent fall in Butterfield’s stock price over the five days of trading.The BSX Insurance Index gained 1.54 points to close on 1,714.54.