Shares of Adani Group companies fell Monday, after a new report from U.S. short seller Hindenburg accused the chair of India's capital markets regulator of having conflicts of interest that prevented an in-depth probe of fraud allegations.

Adani Group companies lost roughly $2.4 billion in market value Monday, recovering by the end of the session from an earlier reported fall of as much as $13.4 billion.

The Indian group's flagship firm Adani Enterprises slipped as much as 5% in early morning deals, before paring losses. Shares of Adani Total Gas, Adani Power, Adani Wilmar and Adani Energy Solutions also fell sharply on the news.

Hindenburg published a report Saturday which alleged that both Madhabi Puri Buch, the chair of the Securities and Exchange Board of India (SEBI), and her husband, Dhaval Buch, previously held investments in offshore funds also used by the Adani Group.

Hindenburg said it does not think SEBI "can be trusted as an objective arbiter in the Adani matter."

Madhabi Puri Buch and Dhaval Buch both denied wrongdoing and said the report's claims were baseless.

Adani on Sunday rejected the latest allegations from Hindenburg, describing the report as a "red herring." The company said its overseas holding structure was fully transparent.

Led by billionaire Gautam Adani, the multinational conglomerate operates across a wide range of sectors, including commodities trading, airports, utilities and renewable energy.

Hindenburg's latest report comes roughly 18 months after it first accused the Adani Group of stock manipulation and corporate fraud. The findings, published in January 2023, led to a stock rout in excess of $100 billion.

Adani has denied all the allegations and shares have partially recovered.

— CNBC's Ganesh Rao contributed to this report.

Correction: This story has been updated to correct that the market value of Adani Group companies fell as much as $13.4 billion earlier in the day.