HONG KONG'S banks responded to the latest cut in United States interest rates yesterday by lowering short-term deposit and prime lending rates by a quarter of a percentage point. From Monday, the interest rate on savings deposits will fall from four per cent to 3.75 per cent while most banks will cut their prime lending rate, on which the mortgage rate is based, from 8.75 per cent to 8.5 per cent. The standard mortgage rate falls to 10.25 per cent. Anticipation of the Hong Kong Association of Banks' move sent share prices to another two-year high, with the Hang Seng Index closing the day up 106 points at 11,469. Gold continued its surge, hitting a six-year high in London after rising strongly in the territory earlier in the day. It was fixed at US$416.25 (HK$3,214.70) per troy ounce last night, its highest level since February 1990.