They said Karti Chidambaram deposed before the investigating officer (IO) of the case as per the scheduled summons for today.
This was the second time he appeared before the ED in this case after he was first grilled by the agency on January 18.
The central probe agency had earlier summoned Karti Chidambaram on February 2 after which he informed them that he would be unable to depose as he had an interlocutory application pending in the Supreme Court in this case.
The ED then summoned him for today.
It is understood that he today told the IO that he was appearing before the agency "under protest".
Talking to reporters on January 18, Karti Chidambaram had said that he told the investigators what he had earlier "clearly stated in his petitions in the court" (in the case).
The former Union minister's son was referring to his moving of various courts, including the Madras High Court and the Supreme Court, in response to the ED's action against him.
The central probe agency had registered the case against him and others in May last year.
It had registered an Enforcement Case Information Report (ECIR), the ED's equivalent of a police FIR, against the accused named in a CBI complaint, including Karti Chidambaram, INX Media and its directors -- Peter and Indrani Mukerjea.
The ECIR was lodged under the provisions of the Prevention of Money Laundering Act (PMLA).
The sources said the ED was probing the alleged "proceeds of crime" generated in this case.
The CBI had also carried out searches at the houses and offices of Karti Chidambaram across four cities for allegedly receiving money from the media firm owned by the Mukerjeas to scuttle a tax probe.
The Chidambarams, however, have denied all the charges made against them.
The CBI had filed the FIR against Karti Chidambaram and the Mukerjeas on charges of criminal conspiracy, cheating, receiving illegal gratification, influencing public servants and criminal misconduct.
The agency has alleged that Karti Chidamabaram received money from INX Media for using his influence to manipulate a tax probe against it in a case of violation of Foreign Investment Promotion Board (FIPB) conditions to receive investment from Mauritius.
The CBI has said that it also seized vouchers of Rs 10 lakh which were allegedly paid for the services.
The vouchers were issued in favour of the Advantage Strategic Consulting (P) Limited, a firm "indirectly" owned by Mr Chidambaram's son.
The former finance minister, after the CBI searches on May 16 last year, had issued a strong statement against the raids, saying the government was using the CBI and other agencies to target his son.
"The FIPB approval was granted in hundreds of cases," the senior Congress leader had said.
The CBI FIR was made out against Karti Chidambaram, his company Chess Management Services, the Mukerjeas (currently in jail on charges of murder of their daughter Sheena Bora), INX Media, Advantage Strategic Consulting Services and its director Padma Vishwanathan.