Tata Group Chairman Ratan Tata at press conference in Bombay

The share offering opened on 29 July, and was sold out by the second day.

"We knew that we had a good story going . The retail application could be crossing a million anytime now," said S Mahalingam, TCS's financial officer.

The debut share offering will rake in $1.2bn (�660m) for the software firm, which is being spun out from Tata group

It is one of India's biggest private business empires with interests which range from tea to trucks.

A 60% portion of the issue, which was set aside for institutional investors, was oversubscribed eight times.