The BSE benchmark Sensex declined by over 27 points in early trade today .The 30-share barometer declined by 27.52 points, or 0.16 per cent, to 17,251.33, as stocks of auto, realty and refinery sectors fell on profit-booking after recent strong gains.The Sensex rose by almost 176 points in the previous three sessions.Similarly, the wide-based National Stock Exchange index Nifty shed 11.65 points, or 0.22 per cent, to 5,231.05