The Bermuda Stock Exchange (BSX) fell nearly 60, or 6 percent, last week to close at 992.86.Butterfield Bank shares plunged 8.7 percent to close the week at $1.05, on a volume of 250,261.The Bank’s shares’ 52-week high has been $1.60, and the 52-week low had been $1.06.Argus Group and KeyTech also dropped.Argus shares fell 6.7 percent to $4.20 last week, on a volume of 1,000.KeyTech shares fell 9.3 percent, or 54 cents, to finish the week at $5.26.