The Bombay Stock Exchange benchmark Sensex fell by over 46 points in the opening trade today. Sensex was 17915, down by 21 points when reports last came in. Brokers said that the trading sentiment turned bearish after IT bellwether Infosys Technologies reported a 2.42 per cent decline in its consolidated net profit for the first quarter ended June 30, 2010. Besides emergence of profit-booking by funds as well as retail investors also weighed on the sentiment.