The Sensex opened with a huge positive gap of 43 points at 9493, and went on to scale a high of 9556. The index has now gained 81 points at 9531.Reliance Energy and HDFC have rallied 2.5% each to Rs 637 and Rs 1,208, respectively.Tata Steel, HDFC Bank, ITC, Wipro, Gujarat Ambuja, ICICI Bank, ONGC, Infosys, Tata Power, Grasim, Hero Honda and Maruti are up 1-2% each.Hindalco, Cipla, BHEL and Bharti are the only losers among the index stocks.