The markets tumbled from higher levels in late morning deals and remained weak thereafter.
While selling pressure continued in the afternoon trades; steep slide in tech, heavyweight, cement and other select old economy stocks towards the closing bell saw the index slump below the crucial 6,400-mark to touch an intra-day low of 6,396.
The Sensex finally ended lower above the psychological mark at 6,414 - down 37 points from the yesterday's close. The Nifty lost 10 points to 2,035.
Infosys declined 1.55% (Rs 33) to Rs 2,083. While Satyam lost 2.36% (Rs 10) to Rs 407, Wipro was down 1.76% (Rs 14) at Rs 756.
SBI declined 1.48% (Rs 9) to Rs 594. While ICICI Bank was down 1.45% (Rs 5) at Rs 360, HDFC Bank ended with a small loss of Rs 2 at Rs 493.
ITC ended Rs 6 lower at Rs 1,303, and HLL was down a rupee at Rs 143. Reliance attracted considerable buying support and advanced nearly 2% (Rs 9) to Rs 495.
Grasim declined 2.55% (Rs 33) to Rs 1,277. While Gujarat Ambuja slipped 2.24% (Rs 9) to Rs 386, ACC was down a per cent (Rs 3) at Rs 316.
Dr. Reddy's was down 1.27% (Rs 11) at Rs 850 and Cipla lost 2% (Rs 6) to Rs 304. Ranbaxy, however, closed up a per cent (Rs 8) at Rs 1,257.
Bajaj moved up 1.81% (Rs 20) to Rs 1,119, and Maruti added 2.11% (Rs 10) to Rs 469. Tata Motors, however, was down Rs 2 at Rs 502.
Zee dropped 3.41% (Rs 6) to Rs 173. Bharti, however, added 2.16% (Rs 4) to Rs 204.