Shares of Tata Consultancy Services (TCS) plunged more than 3 per cent in the morning trade on Tuesday as its promoter Tata Sons sold around 2.3 crore shares, or 0.65 per cent of equity stake, in the IT services major through block deals. TCS shares tumbled 3.30 per cent to a low of Rs 4,015.65 apiece on the NSE. On the BSE, the stock plunged 3.15 per cent to Rs 4,014 per piece, emerging a major drag on the benchmark Sensex.