Shares of IT companies fell in the morning trade today with the sectoral index plunging almost 3 per cent after software services firm Cognizant lowered its full-year forecast on weak demand.

Country's biggest IT firm TCS was the worst performer among the BSE Sensex blue-chips, shedding 4.96 per cent to touch an early low of Rs 1,210.60 on the BSE.

Similarly, Infosys lost 4.12 per cent to Rs 2,330.30, while Wipro was down 3.89 per cent to Rs 395.90.

In the broader market, HCL Tech was trading lower by 2.62 per cent, while Hexaware Tech slipped 3.04 per cent.

Following the losses in these stocks, the BSE IT index was quoting at 5,538.69, down 2.99 per cent and was the worst performer among the 13 sectoral indices.

Cognizant yesterday posted 17 per cent rise in net profit at $ 243.7 million for January-March, 2012, but lowered its full-year forecast on low demand.

The company lowered its full-year revenue outlook to at least $ 7.34 billion, from $ 7.53 billion forecast earlier.

"Due to a slower than anticipated acceleration in demand, as we entered the second quarter, we are adopting a more conservative stance for the remainder of the year and revising our guidance to at least 20 per cent revenue growth for 2012," Cognizant Chief Executive Officer Francisco D'Souza had said.

The broader stock market has been weak since morning and at 11.51, the BSE index Sensex was down 55.41 points at 16,857.30. At one point it was down over 140 points.