CBI had registered a preliminary enquiry on the complaint of STC that some private companies made payments to its officials and started a probe last October.
Agency sources said Singh's statement has been recorded in connection with the probe into allegations that he as Steel Minister had also received payoffs of Rs 2.8 crore from a Mumbai-based steel company.
STC had given a complaint on which Aam Admi Party leader Prashant Bhushan also wrote to the CBI Director and approached Delhi High Court seeking a probe into the matter.
The complaint filed by STC and Bhushan has been clubbed, the sources said. The sources refused to give details of the mode of questioning but said his statement has been taken on record in the probe.
In the representation given by Bhushan, it was alleged that Income Tax returns and affidavits filed during Singh's nomination show dubious transactions which needed to be probed by the agency.
The issue was also raised by Leader of Opposition in Rajya Sabha Arun Jaitley who wrote to Prime Minister Manmohan Singh alleging that Virbhadra Singh recieved kickbacks from a private steel firm during his tenure as Union steel minister.
Virbhadra Singh, who was steel minister between May 2009 and January 2011, has denied the charges.