Butterfield Bank closed down 1 cent, or 0.71 percent, yesterday to end at $1.38 on the Bermuda Stock Exchange.Some 2,700 of Butterfield’s shares traded.KeyTech closed unchanged at $6 as 5,000 of the company’s shares changed hands.Overall the BSX closed down 4.72, or 0.41 percent, at 1,160.67