The Sensex opened with a negative gap of 84 points at 17,991. Follow-up selling has pushed the index deeper into red and is now down 231 points at 17,844.The NSE Nifty is down 65 points at 5,216.Reliance Communications, HDFC and ICICI Bank have plunged over 3% each to Rs 587, Rs 2,770 and Rs 1,180, respectively.HDFC Bank has dropped 2.5% to Rs 1,530, and Bharti Airtel has shed 2% at Rs 870.Hindustan Unilever, NTPC and BHEL have slipped 1.8% each to Rs 217, Rs 201 and Rs 2,185, respectively.ITC has shed 1.7% at Rs 202, and DLF has declined 1.5% to Rs 830.Tata Motors and Larsen & Toubro have dropped 1.3% each to Rs 728 and Rs 3,508, respectively.Grasim, Reliance and SBI are down over 1% each at Rs 2,830, Rs 1,606 and Rs 2,241, respectively.Mahindra & Mahindra has moved up 1.7% to Rs 669.Infosys and Satyam have advanced over 1.5% each to Rs 1,582 and Rs 429, respectively.Ranbaxy has gained 1.4% at Rs 421. Wipro and Bajaj Auto are up over 1% each at Rs 418 and Rs 2,350, respectively.