Lack of follow-up buying in the market led the Sensex slip into the negative zone. The index is now down 25 points at 10,426.ACC has shed 3% to Rs 763. Dr.Reddy's has slipped 2.8% to Rs 1,303.Bajaj Auto and Bharti Airtel are down 2% each at Rs 2,661 and Rs 359, respectively.Hindalco, Grasim and HDFC Bank are the other prominent losers among the Sensex stocks.Hero Honda has rallied 2.6% to Rs 782. HDFC, Larsen & Toubro, NTPC and Reliance Energy have gained over 1% each.