The Sensex is trending lower on the back of heavy selling pressure in index heavyweights. The Sensex is now down 662 points at 10,147.

The NSE Nifty is down 203 points at 3,135.

Mahindra & Mahindra and Reliance [Get Quote] have slumped 9.7% each to Rs 437 and Rs 1,372, respectively.

Wipro [Get Quote], TCS [Get Quote] and Jaiprakash Associates [Get Quote] have crashed around 9% each to Rs 252, Rs 494 and Rs 66, respectively.

Tata Motors [Get Quote] has tumbled 8.7% to Rs 258. Hindalco [Get Quote], Infosys [Get Quote] and Sterlite have plunged around 8% each to Rs 73, Rs 1,225 and Rs 269, respectively.

Grasim [Get Quote] has dropped over 7% to Rs 1,383. Tata Power [Get Quote] has shed 6.5% at Rs 743.

BHEL, Bharti Airtel [Get Quote] and HDFC Bank [Get Quote] have slipped nearly 6% each to Rs 1,313, Rs 677 and Rs 1,069, respectively.

ACC, Larsen & Toubro and Satyam [Get Quote] are down around 5.5% each at Rs 514, Rs 843 and Rs 257, respectively.

Hindustan Unilever, however, has surged 2.5% to Rs 237.

Earlier Report

The Sensex opened with a negative gap of 524 points at 10,285, and soon tanked to a fresh calendar year low of 10,151.

The index is now down 450  points at 10,360. The NSE Nifty is down 139 points at 3199.

Reliance and TCS have slumped over 8.5% each to Rs 1,386 and Rs 496, respectively.

Jaiprakash Associates and Sterlite have plunged 8% each to Rs 67 and Rs 269, respectively.