The Indian equity benchmarks staged a gap up opening on Thursday ahead of weekly expiry of index futures and option contracts amid strong global cues and touched their highest levels in four months. The Sensex rose as much as 6668 points and Nifty 50 index reclaimed its important psychilogical level for the first time since April. Infosys, ICICI Bank, Tata Consultancy Services, HDFC Bank, Reliance Industries and HDFC were among the top movers in the Sensex.