Falls in the share prices of Butterfield Bank and KeyTech Ltd drove the local stock market lower last week.Butterfield tumbled three cents, or 2.3 percent, to close on $1.28, as nearly 72,000 shares traded during the five days. The bank’s preference shares also fell slightly, dipping $5, or 0.4 percent, to $1,230, as 53 of the shares changed hands.Telecommunications group KeyTech Ltd slid 10 cents, or 1.7 percent, to end the week on $5.90, on the trading of 1,125 shares.Ascendant Group Ltd and BF&M Ltd also traded during the week, without changing value.The Royal Gazette / BSX Index closed the week on 1,138.96, down 15.59 points, or 1.36 percent. Share volume topped 75,000, while turnover was just shy of $200,000.