Chief executives and promoters of 10 companies are among 63 people under investigation in the 2G spectrum scam, the Central Bureau of Investigations on Tuesday told the Supreme Court, according to the Economic Times.

Meanwhile, the government said it was debating the merits of cancelling licenses of companies that had not rolled out services on schedule. 

The CBI did not name all 10 companies, but so far executives from Swan Telecom (now Etisalat), Unitech Wireless (Uninor), Reliance Communications, Tata Teleservices , Tata Realty, Loop Telecom, Datacom (Videocon), S Tel, Sistema Shyam and Essar have been called to CBI offices to answer questions, chiefly relating to tortuous shareholding structures that the CBI alleges reflect shell companies and payoffs.