The Bombay Stock Exchange benchmark Sensex declined by over 12 points in opening trade today as funds and investors locked-in gains amid weak global cues. The 30-share barometer, which had gained over 256 points in the last two sessions, fell to 20,104 level in early morning trade. Realty, IT and banking sector stocks were under slight pressure and dragged the Sensex down. The wide-based National stock Exchange, Nifty index also slipped by nearly 8 points to 6,027. Meanwhile, Hong Kong's Hang Seng index was trading lower by 1.06 per cent, while Japan's Nikkei shed 0.61 per cent in the early trade. The US Dow Jones Industrial Average ended point 44 per cent down in yesterday's trade.