Argus Group Holdings Ltd. was the biggest loser on The Bermuda Stock Exchange (BSX) last week, dropping 22.41 percent ($1.30).The insurer traded 7,413 shares during the week.The Ascendant Group Ltd. fell one percent (15 cents) to $14.85, with 6,000 shares changing hands.But Butterfield Bank’s common shares rose four percent (five cents) to $1.30, as 24,600 shares were transacted.The bank also traded 118 preference shares, but their share price held firm at $1,225.BF&M Ltd. also climbed 1.78 percent (25 cents) to $14.25, with 400 shares changing hands.KeyTech Ltd., meanwhile, edged up 1.44 percent (10 cents) to $7, as 12,800 shares were transacted.Overall the Index slipped 16.75 points (1.45 percent) to 1,152.79, with 51,213 shares worth BD$244,091.15 and 509 shares worth US$148,733.70 traded.The BSX Insurance Index, however, was up three points (0.29 percent) at 1,049.