The Sensex has rebounded into the positive zone and is now up four points at 12,790.Tata Steel has advanced over 2% to Rs 448. Cipla and HDFC have surged 1.7% each to Rs 233 and Rs 1,521, respectively.Grasim, ACC, Gujarat Ambuja, HLL and Tata Motors are up around 1% each at Rs 2,088, Rs 722, Rs 106, Rs 200 and Rs 688, respectively. ONGC and Dr.Reddy's are the prominent losers.