The Sensex opened 11 points lower at 8,944, and since then has extended losses. The index is now down 120 points at 8,835.
ACC has slumped nearly 5% to Rs 533. Sterlite has plunged 4.5% to Rs 242, and Maruti has shed 3.5% at Rs 672.
Mahindra & Mahindra has tumbled nearly 3% to Rs 312. Grasim, Bharti Airtel and ONGC have slipped 2% each to Rs 1,429, Rs 639 and Rs 701, respectively.
Reliance Communications and Infosys are down around 1.5% each at Rs 156 and Rs 1,218, respectively.