The Sensex slumped to a low of 10,498 - down 243 points from the day's high. The index is now down 162 points at 10,563.The selling can be attributed to the huge selling by foreign institutional investors (FIIs) in the derivatives segment yesterday. The FIIs were net sellers of index futures to the tune of Rs 1,488 crore and net sellers of stock futures worth Rs 395 crore.Hindalco has slumped over 4% to Rs 160.HLL, HDFC and Bharti Tele have dropped 3% each to Rs 245, Rs 1,304 and Rs 391, respectively.Tata Steel, Maruti, Tata Motors and HDFC Bank have declined over 2% each to Rs 456, Rs 895, Rs 890 and Rs 744, respectively.Tata Power, Ranbaxy, ONGC, HDFC Bank, ACC, Reliance, Bajaj Auto, Wipro, ITC and ICICI Bank are reeling under heavy selling pressure.Cipla is the only prominent gainer among the Sensex stocks.The market breadth is fairly negative. Out of 2,525 stocks traded so far, 1,510 have declined, 935 have advanced and the rest are unchanged.