Two rival insurers moved in opposite directions in Bermuda Stock Exchange (BSX) trading last week.Argus Group Holdings Ltd shot up 15 cents, or 4.3 percent, to close the week on $3.65 as 30,000 shares traded.BF&M Ltd fell 25 cents, or 1.5 percent, from its 52-week high of $16.25 and closed the week on $16 after 1,300 shares changed hands.Butterfield Bank was the most heavily traded stock, but its price remained unchanged on $1.27 as 68,556 shares were exchanged. The bank’s preference shares also traded with 125 shares changing hands, as the price stayed on $1,215.The Royal Gazette / BSX Index was virtually flat for the five days of trading, closing Friday at 1.096.2, up 0.98 of a point, or 0.08 percent.Volume for the week topped 108,000 shares, while turnover exceeded $433,000.