CBI is likely to question all nine companies which were awarded 2G licences in 2007-08 before March 1.
The
agency has already interrogated Reliance ADAG chairman Anil Ambani, Unitech MD Sanjay Chandra and Videocon chairman Venugopal Dhoot.
Shahid Balwa, managing director of DB Realty, which is in a joint venture with UAE-based Etisalat group, was arrested earlier this month.