Equity benchmark BSE Sensex turned volatile on Monday, dropping over 150 points in opening session amid stock-specific action after a rejig of its constituents.

Yes Bank, Vedanta, Tata Motors and Tata Motors DVR have exited the index to make way for Titan Company, UltraTech Cement and Nestle India.

The 30-share BSE index was trading 60.68 points or 0.15 per cent lower at 41,620.86 in early session.Similarly, the broader NSE Nifty fell 11.05 points or 0.09 per cent to 12,260.75.

On the other hand, RIL was the top loser, shedding up to 2.09 per cent, followed by Bharti Airtel, Nestle, Bajaj Auto, Techm, HDFC Bank and ICICI Bank.

In the previous session, the 30-share gauge closed 7.62 points, or 0.02 per cent, higher at 41,681.54. Similarly, the broader NSE Nifty rose 12.10 points, or 0.09 per cent, to its new record of 12,271.80.

Meanwhile, on a net basis, foreign institutional investors bought equities worth Rs 338.86 crore, while domestic institutional investors sold shares worth Rs 285.41 crore on Friday, data available with stock exchange showed.

Such exercises are done by the central bank when the proceeds from sale of short term securities are used to buy long-term government securities or bonds in a bid to bring down interest rates on long-term securities.