It was a down day on the Bermuda Stock Exchange.Shares of KeyTech slid 55 cents or 9 percent yesterday with 2,401 shares trading to close at $5.55.Bermuda Aviation Services lost 12.9 percent or 40 cents with 8,700 shares trading. The stock closed at $3.50.And shares of Argus sank 15 cents or 4 percent to close at $3.60.Overall, the BSX lost 7.79 percent to close the week at 1,071.65 with 13,653 shares trading hands worth $ 12,402.22.