The Sensex opened with a positive gap of 60 points at 13,346, but profit-taking at higher levels, following last week's rally, saw the index slip into negative zone in early deals.The index drifted to low of 13,091 - down 255 points from the day's open - on account of weakness in auto, banking and technology stocks. The Sensex finally settled with a loss of 162 points at 13,124.The BSE Mid-cap and Small-cap indices ended with marginal losses of 0.5% each at 5377 and 6426, respectively.The Bankex dropped 2% to 6687. While the Auto index slipped 1.8% to 4950, the IT index declined 1.2% to 5009.The market breadth was fairly negative - out of 2,642 stocks traded, 1,741 declined, 842 advanced and 59 were unchanged today.LOSING GROUNDTata Motors tumbled 4.5% to Rs 754. HDFC Bank plunged 3.5% to Rs 976.Maruti and Wipro shed 2.5% each to Rs 819 and Rs 586, respectively.Reliance Energy, TCS, ICICI Bank, HDFC and Infosys slipped around 2% each to Rs 475, Rs 1,261, Rs 876, Rs 1,564 and Rs 2,057, respectively. Hero Honda, Hindalco and Cipla dropped 1.7% each to Rs 668, Rs 133 and Rs 238, respectively. ACC shed 1.5% to Rs 735.SBI declined 1.3% to Rs 1,014. ITC, BHEL, NTPC, Reliance, Larsen & Toubro and Gujarat Ambuja were down around 1% each to Rs 143, Rs 2,255, Rs 143, Rs 1,365, Rs 1,616 and Rs 104, respectively.Satyam advanced 1.7% to Rs 472. ONGC added 1% to Rs 853.MOST ACTIVE COUNTERSIndiabulls Real Estate topped the value chart with a turnover of Rs 261.70 crore followed by Reliance Communications (Rs 130.15 crore), MindTree (Rs 95.40 crore), Page Industries (Rs 87.40 crore) and IFCI (Rs 80.95 crore).IFCI led the volume chart with trades of around 2.50 crore shares followed by Indiabulls Real Estate (85.50 lakh), Reliance Petroleum (49.40 lakh), debutant Sparsh BPO (49 lakh) and Reliance Communications (30.50 lakh).