The Sensex has slipped into the negative zone and is now down 17 points at 13,635.Satyam and Tata Motors have slipped around 1.5% each to Rs 478 and Rs 915, respectively.HDFC, HDFC Bank and Larsen & Toubro are down over 1% each to Rs 1,575, Rs 1,017 and Rs 1,447, respectively.Gujarat Ambuja has soared 3% to Rs 141. ONGC has rallied 2% to Rs 928.HLL, Bharti Airtel and ITC are the other major gainers.Out of 2,583 stocks traded so far, 1,689 have advanced, 851 have declined and the rest are unchanged today.