The Sensex at the Bombay Stock Exchange fell by 18 points in early trade today as funds and retail investors booked profits amid a weak trend in the Asian region. The 30-share barometer fell by 18 points to 19,965 with stocks of banking, IT and metalsuccumbing to profit-booking. It had crossed the 20,000-markafter two years in yesterday's trade. The index had gained nearly 324 points in the last two sessions.Similarly, the wide-based National Stock Exchange index Nifty, moved down by 12.80 points to 6,043.80.In the Asian region, Hong Kong's Hang Seng fell by 0.50 per cent, while Japan's Nikkei declined by 1.52 per cent in early trade today.In the US market, Dow Jones Industrial Average ended 0.20 per cent higher in yesterday's trade.