Shares of the six Adani group companies, which are in the business of operating airports and ports, generating and distributing electricity, and coal and gas trading, closed between 1.1%-4.8% lower on Monday.
"The Securities and Exchange Board of India (SEBI) is investigating some Adani Group companies with regard to compliance with SEBI Regulations," Chaudhary said, without disclosing the companies involved.
"The Directorate of Revenue Intelligence (DRI) is investigating certain entities belonging to the Adani Group," he said.
A spokesman for the Adani group said the company had not received any enquiries from the Securities and Exchange Board of India (SEBI) "recently."
"We have made full disclosure to SEBI on specific information requests from them in the past. However, we have not received any communication or information requests recently," he said.
A matter pertaining to a show cause notice sent by the Directorate of Revenue Intelligence (DRI) five years ago was sub-judice, the spokesman said.
Stocks of companies controlled by Indian billionaire Gautam Adani recorded their biggest-ever decline in the week ended June 18, after Indian newspaper Economic Times reported that the accounts of three Mauritius-based foreign investors in Adani companies had been frozen.
Shares in the six Adani companies have fallen between 12.9%-44.9% in the five weeks after the Economic Times report. The stocks have cumulatively lost over $37.6 billion in just over a month following the report, even after Adani rejected the article as "blatantly erroneous."
($1 = 74.6060 Indian rupees)
(Reporting by Sudarshan Varadhan; Editing by Raju Gopalakrishnan and Bernadette Baum)
By Sudarshan Varadhan