The Sensex opened with a positive gap of 113 points at 18,228, and touched a high of 18,257. The index has slipped into the negatie zone and is now down 13 points at 18,102.The NSE Nifty is down 11 points at 5,292.Bajaj Auto has advanced 2.5% to Rs 2,230, and Mahindra & Mahindra have gained nearly 2% at Rs 630.NTPC has moved up 1.5% to Rs 207, and Reliance Communications has added 1.3% to Rs 620.Larsen & Toubro and Reliance Energy are up 1% each at Rs 3,575 and Rs 1,728, respectively.ONGC has shed 2.5% at Rs 1,007. Bharti Airtel and Tata Motors have slipped 1.7% each to Rs 866 and Rs 738, respectively.BHEL and Hindalco have dropped 1.3% each to Rs 2,230 and Rs 176, respectively.DLF is down 1% at Rs 870.