New Delhi: Shares of IT companies tumbled up to 3.7 per cent on Friday after Cognizant reported over 15 per cent drop in net income for the quarter ended March, and slashed its full-year revenue growth outlook. On the BSE, TCS fell 3.70 per cent, Hexaware Technologies 2.73 per cent, Tech Mahindra 2.16 per cent, HCL Tech 1.40 per cent, Wipro 0.87 per cent and Infosys Ltd 0.84 per cent. TCS was the worst hit among the Bombay Stock Exchange (BSE) 30-share pack. Led by the decline in these scrips, the BSE Information Technology index fell 1.91 per cent to close at 15,659.96. The US-headquartered Cognizant, which has a significant portion of its employees based in India, revised its full-year 2019 revenue growth outlook to 3.6-5.1 per cent in constant currency, significantly less than 7-9 per cent projected just months ago. Cognizant follows January-December as financial year.