Mumbai/IBNS, May 12 -- The Indian stock market on Tuesday witnessed a sharp selloff as IT, financial and broader market stocks plunged during the opening hour amid rising geopolitical tensions and weak investor sentiment.

IT stocks emerged as the biggest laggards, with the Nifty IT index nosediving nearly 4 percent.

Among the major losers on the BSE Midcap Index were Persistent Systems, JSW Infrastructure and Kaynes Technology.

On the gaining side, Oil India surged almost 7 percent and emerged as the top gainer on the BSE Midcap Index. Other gainers included Biocon, Oberoi Realty, Blue Star and NMDC.

Meanwhile, ONGC surged over 5 percent to become the top Nifty gainer as oil stocks benefitted from rising crude prices.

The market weak...