The BSE benchmark Sensex today slipped from an almost three-year high by falling nearly 32 points in early trade as funds and retail investors booked profits after recent gains amid a weak trend in other Asian markets.The 30-share barometer declined by 0.15 per cent, to 20,862. The index had gained over 478 points in the previous two sessions. Stocks of banking, oil and gas, realty, auto and FMCG sectors were the major losers.Similarly, the National Stock Exchange index Nifty fell by9.30 points, or 0.15 per cent, to over 6,195.