Shares of Butterfield Bank tumbled $1.50, or 6.1 per cent, to $23 after 3,000 traded on The Royal Gazette/BSX Index.On the New York Stock Exchange, the bank’s shares were down 71 cents, or 3.19 per cent, at $21.55.On the local exchange, shares of Somers Limited fell 50 cents, or 3.7 per cent, to $13 after 2,800 were exchanged. The Royal Gazette/BSX Index was down 70.79 points, or 3.93 per cent, at 1,731.44, while the BSX Index was down 14.67 points, or 1.09 per cent, at 1,335.83.