Mumbai, The BSE Sensex surged 542 points during the initial trade on Monday to cross the 40,000 mark.

It has, however, retreated from the day's high of 40,010.17 points.

Around 9.50 a.m., it was trading at 39,861.62, higher by 394.31 points or 1.00 per cent from the previous close of 39,467.31.

Healthy buying was witnessed in finance, banking and oil and gas stocks.

The Nifty50 on the National Stock Exchange was trading at 11,764.30, higher by 116.70 points or 1.00 per cent from its previous close.