Bermuda National Ltd, parent company of the Bermuda Commercial Bank, was the biggest advancer in Bermuda Stock Exchange trading last week, gaining 2.1 percent to reach a 52-week high.The company’s shares gained 25 cents to close the five days of trading on $12.25, on the trading of 10,000 shares.Butterfield Bank also gained ground, climbing two cents, or 1.4 percent, to close the week on $1.40, as 5,500 of its shares traded. The bank’s preference shares also rose 0.4 percent, adding $5 to close at $1,195 on Friday.Ascendant Group Ltd, owner of Belco, also traded slightly higher, gaining one cent, or 0.1 percent, to close the week on $11.01.More than 19,000 shares traded on the BSX last week generating turnover of more than $277,000. The Royal Gazette/BSX Index gained 11.02 points, or 0.95 percent, to close on Friday at 1,154.46.