Shares of SBI today plunged about 5 per cent even as the company reported over two-fold jump in net profit for the first quarter ended June 30, 2012. Following the results, shares of the bank fell sharply by 4.56 per cent to Rs 1,882 on the BSE. At the NSE, the scrip plunged 4.71 per cent to Rs 1,876. The stock was the biggest loser on the Sensex, which was trading flat in afternoon.