The Sensex is now down 730 points at 16,735.The NSE Nifty is down 233 points at 4,887.Reliance Energy has slumped 12% to Rs 1,726. HDFC and Reliance have tumbled around 6.5% each to Rs 2,615 and Rs 2,270, respectively.Mahindra & Mahindra, Reliance Communications and ONGC have plunged 6% each to Rs 606, Rs 607 and Rs 938, respectively.ICICI Bank has dropped nearly 6% to Rs 1,005, and SBI has shed 5.4% at Rs 2,073.NTPC and Larsen & Toubro have slipped 5% each to Rs 193 and Rs 3,350, respectively.Bajaj Auto, Bharti Airtel and HDFC Bank have declined 4.3% each to Rs 2,120, Rs 845 and Rs 1,385, respectively.Satyam has surged 3.5% to Rs 424. Infosys has advanced 2% to Rs 1,582, and TCS has gained 1.5% at Rs 914.The market breadth is extremely negative - out of 2,584 stocks traded so far, 2,325 have declined, 223 have advanced and 36 are unchanged.