The Royal Gazette / Bermuda Stock Exchange Index fell by almost 1.3 percent last week, as Butterfield Bank’s share price slipped.The bank’s shares fell three cents, or 2.3 percent, to $1.27 on the trading of just 900 shares over the five days. The bank’s preference shares also dipped fractionally, falling $1, or 0.1 percent, to close on $1,231 as 34 shares changed hands.Insurer Argus Group Holdings Ltd gained 16 cents, or 3.6 percent, as 2,200 shares were exchanged.The Index fell 14.22 points, or 1.28 percent, to close the week on 1,107.57.