The Bombay Stock Exchange benchmark Sensex fell by over 86 points in the opening trade today. The Sensex was trading at 20,177 down by over 43 points a short while ago.Analysts said the fall in Sensex is largely due to continued profit-booking by funds and retail investors.Meanwhile, in Asian markets, the Hong Kong's hang Seng index quoted higher by 0.30 per cent, while Japanese Nikkei was marginally up by 0.68 per cent in the morning trade today. In the US, Dow Jones Industrial Average had ended 0.05 per cent higher in Tuesday's trade.