The Sensex on Friday tumbled around 1,000 points in the opening session, mainly due to weakness in IT and financial stocks amid a weak trend in global markets. The BSE Sensex was trading 980.01 points or 1.66 per cent lower at 57,946.02 in early trade. Likewise, the Nifty 50 fell 283.60 points or 1.61 per cent to 17,322.25. Infosys was the top loser in the Sensex pack, shedding over 2 per cent, followed by Wipro, Tech Mahindra, HCL Tech, HDFC, Bajaj Finance, M&M and Bajaj Finserv. Zomato stocks also plunged by six per cent,