The Indian equity benchmarks surged over 2 per cent on Monday fuelled by a rally in HDFC and HDFC Bank after their boards approved merger of the country's largest mortgage lender HDFC with the country's largest private lender HDFC Bank making way for the country's second largest entity by market capitalisation after Reliance Industries. The Sensex rose as much as 1,568 points and Nifty 50 reclaimed its 18,000 mark after a gap of two-and-a-half months.