The benchmark BSE Sensex shed about 55 points and the NSE Nifty slipped below the 8,400-mark in early deals today. The 30-share index dropped 54.57 points or 0.20 per cent to 27,183.49. In a similar fashion, the NSE Nifty fell below 8,400-mark, shedding 21.15 points or 0.25 per cent to 8,379.20.