The Swan Telecom is alleged to be a front company for the Anil Ambani Group and was ineligible to get 2G licence and spectrum in 2008.
This was also pointed out by the government auditor CAG in its report in November last year.
Sources privy to the investigation in the CBI said the agency would be approaching the Company Law Board soon to go into the equity pattern of the Swan telecom which may direct the Registrar of Companies functioning under Ministry of Corporate Affairs to verify the details.
Reliance Group Chairman Anil Ambani was questioned for over three hours by the CBI yesterday in this regard and was also brought face to face with jailed former Telecom Minister A Raja for over an hour. The duo remained "non-cooperative" when both of them met.
The investigators repeatedly questioned the duo last evening over the equity issues of Swan telecom for nearly an hour but both remained "non-cooperative" and stuck to their stand, sources privy to the investigations said today.
The questions pertained to whether Reliance Communication directly or through its subsidiary held more than 10 per cent equity, a threshold for cross-holding in two services providers in the same circle, the sources said.
Swan Telecom, in which Tiger Traders Private Limited have 90.13 and Reliance Telecom Limited 9.87 per cent equity share capital, has been under the scanner over alleged diversion of funds to DMK-owned Kalaignar television.
Ambani, 51, was called to the CBI headquarters yesterday for questioning by the agency in connection with the 2G Spectrum scam.
DB Realty group Managing Director Shahid Usman Balwa, promoter of Swan telecom, is already in the CBI custody.
ADAG had yesterday sought to downplay the calling of Ambani to the CBI saying that "during the course of his weekly visit to New Delhi, Ambani met CBI officials to clarify ongoing issues, relating to telecom matters for the years 2001 to 2010".
The ADAG statement said, "neither Reliance Telecom nor RCOM nor any Reliance ADAG individual, company or affiliate held even a single share in Swan Telecom Ltd at the time of grant of the 2G licence to them in January, 2008, or at any time thereafter".