Butterfield Bank slipped down by a cent in Bermuda Stock Exchange (BSX) trading yesterday.The bank, which was the only domestic board issue to trade, closed on $1.21, representing a fall of 0.8 percent, as 18,900 shares traded.The Royal Gazette / BSX Index fell 4.78 points, or 0.43 percent, to close on 1,112.75.Volume of shares traded was just over 25,000 and the total turnover, including US dollar trades, was more than $98,000.