The Sensex at the Bombay Stock Exchange was trading by 144 points down at 21,026 a short while ago. Earlier the 30-share barometer declined 120 points in opening deals on Thursday on sustained selling by funds amid weak trend in other Asian markets. The National Stock Exchange index Nifty shed 43 points to 6,264. Among other Asian markets, Hong Kong's Hang Seng index was down 0.55 per cent and Japan's Nikkei shed 1.61 per cent in morning trade. The US Dow Jones Industrial Average ended 0.81 per cent lower in Wednesday's trade.