The BSE benchmark Sensex declined by 33 points in early trade today as funds and retail investors engaged in booking-profit amid a weak trend in Asian markets. The 30-share barometer fell by 33 points, or 0.17 per cent, to 18,831. The index gained 183 points in the previous three sessions. Stocks of auto, realty, banking, IT, tech and FMCG sectors declined due to profit-booking.Similarly, the wide-based National Stock Exchange index Nifty fell by 13 points, or 0.23 per cent, to 5,691.Brokers said selling by funds amid weakening trend onother Asian bourses mainly influenced the trading sentiment.In the Asian region, Japan's Nikkei Index was down 1.13 per cent, while Hong Kong's Hang Seng index slightly up 0.12 per cent in early trade.