The Indian equity benchmarks staged a gap up opening on Wednesday led by gains in index heavyweights like Infosys, Reliance Industries, ICICI Bank, HDFC Bank, Kotak Mahindra Bank, HDFC, State Bank of India and Bajaj Finance amid strong global cues. The Sensex rose as much as 428 points and Nifty 50 index was trading firmly above its important psychological level of on 18,150.