The Bombay Stock Exchange benchmark Sensex fell by over 46 points in the opening trade today.It was trading at 19,940, down by over 41 points a short while ago. Analysts said the fall in sensex is due to profit-booking amid weak trend on the other Asian markets. Meanwhile, in other markets in Asia, Hong Kong's Hang Seng index was trading lower by 0.31 per cent, while Japan's Nikkei shed 0.14 per cent in early trade today. In the US, Dow Jones Industrial Average ended 0.17 per cent low at yesterday's close.