The Bermuda Stock Exchange closed down 13.16, or 1.15 percent, at 1,141.30.Butterfield Bank shares fell 2.1 percent, to end the week at $1.37 on a volume of 47,129.Bermuda National fell 1.2 percent to $12.10 on a volume of 10,600.Ascendant Group shares rose 1.7 percent to end the week at $11.20 while KeyTech shares rose 2 cents to $6.12 on a volume of 800.