The ED is also probing a separate money-laundering case in the Aircel-Maxis matter and a chargesheet was filed against Karti Chidambaram by the agency on July 13.
The CBI is probing how P Chidambaram, who was the finance minister in 2006, granted a Foreign Investment Promotion Board (FIPB) approval to a foreign firm when only the Cabinet Committee on Economic Affairs (CCEA) was empowered to do it.
The senior Congress leader's role has come under the scanner of investigating agencies in the Rs 35 billion Aircel-Maxis deal and the INX Media case involving Rs 3.05 billion.
Taking a cue from the CBI FIR, the ED is probing money laundering in the matter.
P Chidambaram and Karti Chidambaram have been questioned by the ED on various occasions, even though the politician has not been arrayed as an accused.
Both Chidambaram and Karti Chidambaram have denied the allegations levelled against them by the CBI and the ED.