Watlington Waterworks Ltd plunged 16.1 percent ($2.25) on The Bermuda Stock Exchange (BSX) last week.The utilities company traded 600 shares to close at $11.70.Bermuda Aviation Services Ltd also fell 11.4 percent (40 cents) to $3.10 with 600 shares changing hands.Butterfield Bank dropped eight percent (10 cents) to $1.15 as 12,296 shares were transacted.BF&M Ltd as well declined 1.6 percent (25 cents) to $15 with 1,700 shares traded.Other traders included the Ascendant Group Ltd (430 shares), Argus Group Holdings Ltd (73) and Butterfield Bank (five preference shares), but all of their share prices remained unchanged.Overall the Index slipped 38.63 points (3.65 percent) to 1,058.15 with 15,699 shares worth BD$54,651.60 and five shares worth US$6,175 changing hands.The BSX Insurance Index, however, rose 12 points (1.2 percent) to 1,012.