The Sensex was trading 465 points down at 18,093 points a shortwhile ago. Snapping 3-day winning spree, the 30-share index today tanked over 221 points in the early trade on fresh selling with banking, realty, metal PSUs and oil and gas sector stocks leading the fall. Sensex had gained over 652 points in the previous three sessions. Similarly, the wide-based National Stock Exchange Nifty was also trading 148 points down at 5,328 points