FIR has been lodged against Jindal Steel and Power Ltd, Gagan Sponge and two others, said sources.
The agency is also carrying out searches at 15 places in Delhi and Hyderabad in connection with the coal scam.
Two firms Nalwa Sponge Iron Ltd and Gagan Sponge Iron Ltd allegedly associated with Jindal, have been under the CBI scanner. Nalwa Sponge and Gagan Sponge got one coal block each at Gare Palma IV, Chhattisgarh, in 2006, and at Amarkonda Murgadangal, Jharkhand, in 2008, respectively. The two coal blocks were being mined in joint venture with Jindal Steel and Power Ltd.
JSPL has five coal blocks allocated to it at Gare Palma IV (Chhattisgarh), Jitpur (Jharkhand), Amarkonda Murgadangal (Jharkhand), Ramchandi (Orissa), Urtan North (Madhya Pradesh). The agency's probe against the private companies revealed that another company, Sandeep Jajodia's Monet Ispat and Energy Ltd, is also linked to JSPL.