Mumbai, Aug 16 : The BSE Sensex fell 3.97 percent on Friday as fears of large scale foreign fund outflows spooked traders. The 30-share benchmark index ended 769.41 points lower at 18,598.18 with 29 of its components closing in the red. The broader 50-share National Stock Exchange (NSE) Nifty index ended 4.08 percent or 234.45 points lower at 5507.85 on Friday. Fears of renewed selling of Indian equities by foreign institutionalised investors due to a tapering of U.S. stimulus and a continuing dive of the rupee, drove stocks down. Meanwhile in the New Delhi bullion market, gold surged Rs 1,310 to Rs 31,010 per 10 grams while silver spurted by Rs 3,270 to Rs 49,320 per kg.