The Royal Gazette/ Bermuda Stock Exchange Index shot up almost 4.5 percent last week after some significant fluctuations in the prices of some of the Island’s major domestic companies.The biggest climber of the week among the BSX domestic board issues was insurer BF&M Ltd, which soared 7.1 percent, or $1, to close on $15, 75 cents below its 52-week high, as 1,000 of its shares changed hands.Insurance rival Argus Group Holdings Ltd had a negative week, however, tumbling 30 cents, or 5.2 percent, to close Friday on $5.50, as 1,415 shares traded.The biggest decline over the five days of trading was telecommunications company KeyTech Ltd, which slid 7.8 percent, or 54 cents, to close the week on $6.36, after 10,500 shares were exchanged.Butterfield Bank had a good week, climbing 3.2 percent, of four cents, as 11,000 shares traded. The bank closed on $1.29 on Friday. Four Butterfield preference shares also changed hands, as the price remained unchanged on $1,225.The Royal Gazette/BSX Index finished the week up 52.33 points, at 1,169.53. Share volumes topped 73,000, while turnover was a little more than $328,400.