The Sensex opened with a significant positive gap of 280 points at 20,018, and soon touched a high of 20,064.The index is now up 245 points at 19,983.ICICI Bank has rallied 2.5% to Rs 1,191.Mahindra & Mahindra, HDFC Bank and NTPC have gained around 2% each at Rs 790, Rs 1,763 and Rs 249, respectively.