The Securities and Exchange Board of India (SEBI) on Thursday dismissed allegations of stock manipulation against billionaire Gautam Adani and his group of companies made by US short-seller Hindenburg Research.

SEBI began investigating Adani Group companies, including Adani Ports, Adani Power and Adani Enterprises, in 2023 after Hindenburg accused them of using tax havens and failing to disclose transactions between related parties.

While the conglomerate denied wrongdoing, the accusations led to a $150-billion sell-off of the group’s stock. The shares have since recovered.

“SEBI has reaffirmed what we have always maintained, that the Hindenburg claims were baseless. Transparency and integrity have always defined the Adani Group,” Gautam Adani, chairman of Adani Group, said on X.

In January, Hindenburg Research founder Nathan Anderson announced he would disband the firm, citing the immense workload. Reuters has reached out to the firm and its founder’s last known email addresses.

Short-sellers like Anderson bet against companies they believe have accounting issues, mismanagement or fraud, which they find usually after a long period of investigation.

The regulator had investigated the Adani conglomerate, its founders, offshore funds that invested in the company on 24 separate sets of violations, including insider trading, stock price manipulation and non-disclosure of related-party transactions.

SEBI said that the transactions between Adani group companies and companies flagged by Hindenburg could not be called related-party transactions and therefore did not violate regulatory norms on disclosures or constitute market manipulation.

In its report in January 2023, Hindenburg had alleged that Adani Ports and Special Economic Zone Ltd, Adani Power Ltd and Adani Enterprises Ltd had structured transactions with three other unrelated companies in a manner to conceal that they were actually between connected parties and ought to have been disclosed to investors.

The regulator dismissed these allegations and said that, according to SEBI rules, these transactions did not happen between connected entities and hence did not require disclosures or the consent of minority investors.

The transactions happened in between April 2012 and March 2021 and SEBI had widened the ambit of disclosures of transactions between connected entities in 2022 and cannot apply its rules retroactively, the regulator noted.

Indian authorities charge Anil Ambani with loan fraud

India’s federal investigating agency said on Thursday it filed charge sheets in cases connected to “fraudulent” transactions between tycoon Anil Ambani’s companies, Yes Bank and firms owned by the lender’s former top boss.

The Central Bureau of Investigation (CBI) said that Yes Bank invested over 50 billion Indian rupees ($567.21 million) in two Ambani-controlled companies in 2017, with approval from the bank’s former CEO Rana Kapoor, despite rating agencies flagging financial risks.

The agency alleged that the funds were later siphoned off, demonstrating a systematic diversion of public money.

CBI said that Kapoor “abused” his position to channel Yes Bank’s funds into financially troubled Ambani group firms, which in return extended concessional loans to companies linked to Kapoor’s family.

The arrangement resulted in a loss of 27.97 billion Indian rupees ($317.29m) to Yes Bank and led to unlawful gains for Ambani’s firms and the companies linked to Kapoor’s family, CBI said.

Anil Ambani’s spokesperson and Rana Kapoor did not immediately respond to Reuters’ requests for comment.