A company owned by Asia's richest man has hit back at a report which accused the firm of "brazen" stock manipulation and accounting fraud.
The Adani Group, founded by Gautam Adani, called the report by a US investment firm "malicious" and "selective misinformation".
BBC reports the group lost almost $US11bn of its market value after the research was made public on Wednesday.
It was considering legal action against New York's Hindenburg Research.
Adani Group was one of India's biggest companies, with operations in a wide range of industries including commodities trading, airports, utilities and renewable energy. It was led by Indian billionaire Adani, who was the world's fourth richest man, according to Forbes magazine.
Hindenburg Research specialised in "short-selling", or betting against a company's share price in the expectation it would fall.
In its report, Hindenburg accused Adani of "pulling the largest con in corporate history". This came days ahead of a planned sale of Adani Group shares to the public.
The report questioned the Adani Group's ownership of companies in offshore tax havens such as Mauritius and the Caribbean. It also claimed Adani companies had "substantial debt" which put the entire group on a "precarious financial footing".
But on Thursday, Adani Group said it was evaluating "remedial and punitive action" against Hindenburg Research in the US and India.
Adani said it had always been "in compliance with all laws".
"The volatility in Indian stock markets created by the report was of great concern and had led to unwanted anguish for Indian citizens," said the group head of Adani's legal team, Jatin Jalundhwala.
"Clearly, the report and its unsubstantiated contents were designed to have a deleterious effect on the share values of Adani Group companies as Hindenburg Research, by their own admission, is positioned to benefit from a slide in Adani shares."
On Thursday, Hindenburg responded to Adani's comments, and said the firm had not addressed "a single substantive issue we had raised".
It also said it stood by its report and would "welcome" legal action, as any claim against it would be "meritless".
The group's flagship firm, Adani Enterprises, was scheduled to begin selling its shares to the public on Friday.
Political response
Opposition politicians who had long alleged Adani had benefited because of his proximity to Indian Prime Minister Narendra Modi were quick to react to the report.
"Considering that detailed research is out in the public domain, it is important that the government of India takes note of the charges made," tweeted Priyanka Chaturvedi, member of parliament and a Shiv Sena party leader.
Another popular South Indian politician, KT Ramarao, called on India's investigative agencies and market regulator to open a probe into the Adani Group's operations.
But regulators were unlikely to initiate any action independently, experts said.
"The Security and Exchange Board of India [which regulates listed companies in India] will act only if there is a specific complaint sent to it. And in this case there isn't," said Shriram Subramaniam, founder and managing director of InGovern Research, a consultancy that advises investors on governance issues.
"There are many allegations in the report that have been the subject of regulatory scrutiny in the past."
The BBC contacted the market regulator but received no response.
While it appeared the decks were clear for Adani Group to proceed with its $US2.4bn public share sale on Friday, the allegations in the report could put some investors off, said Ambareesh Baliga, a financial markets analyst.
But the report could have broader consequences that go beyond the Adani Group.
Andy Mukherjee, a columnist at the news service Bloomberg, said that beyond Adani, there were "many questions about the integrity of the broader Indian market, which is caught between the pressures of financial globalisation and political nationalism".
He added: "Is the Security and Exchange Board of India waiting for a public outcry to go in and clean up the market?"