Local stocks finished the week lower as some of the Island’s largest domestic companies saw their share prices tumble in Bermuda Stock Exchange (BSX) trading.Telecommunications group KeyTech Ltd suffered the biggest fall, sliding nine percent as its share price fell 55 cents to $5.55, with 2.401 shares trading over the five days.Insurer Argus Group Holdings Ltd also had a down week, dipping 20 cents, or 5.3 percent, to close Friday on a new 52-week low price of $3.60, as 10,952 of its shares were exchanged.Fellow insurer BF&M also fell, dipping 30 cents, or 1.9 percent, to $15.55, as 7,000 shares traded.Butterfield Bank also declined, slipping two cents, or 1.6 percent, to $1.23, on the trading of 10,300 shares. The bank’s preference shares also fell by $10, or 0.8 percent, to $1,230, as 44 shares changed hands.The big winner of last week was Bermuda Aviation Services Ltd, whose stock shot up 12.9 percent. BAS shares rose 40 cents to close the week on $3.50, after 9,700 shares were exchanged.Energy company Ascendant Group Ltd also bucked the trend by climbing in last week’s trading, gaining 23 cents, or 1.8 percent, to close the week on $12.75 on the trading of 2,100 shares.The Royal Gazette/BSX Index fell 18.24 points, or 1.7 percent, to close the week on 1,071.65. Nearly 42,500 shares traded and turnover topped $292,000.