Butterfield Bank shares slid nearly four percent yesterday in Bermuda Stock Exchange (BSX) trading.The bank slipped five cents, or 3.93 percent, to $1.22, two cents above its 52-week low, as 10,000 shares changed hands.The Royal Gazette / BSX Index fell 23.7 points, or 2.12 percent to 1,093.44.The 10,000 Butterfield shares were the only ones to trade, producing a turnover for the day of $12,200.