Shares of India's Adani Group companies plunged to 7% as the markets opened on August 12 following US-based short seller Hindenburg's allegations against the chairperson of the Indian market regulator. 

Investors have lost nearly Rs 530 billion ($6.3 billion), with the combined market capitalization of 10 Adani stocks falling to $198.9 billion, Economic Times reported. After opening, Adani Green Energy shares went down 7% to Rs 1,656 on the Bombay Stock Exchange (BSE). 

Adani Total Gas shed around 5%, while Adani Power fell 4%. Other firms, such as Adani Wilmar, Adani Energy Solutions and Adani Enterprises, were down almost 3% in early trading.

In its latest report, Hindenburg alleged that SEBI chairperson Madhabi Puri Buch may not have conducted a proper investigation into Adani Group firms due to a potential conflict of interest. 

It claimed that the SEBI chief and her husband had investments in Bermuda and Mauritius-based offshore funds that Gautam Adani's brother Vinod Adani used to build large positions in Adani Group' shares.

In a post on its X account, the short-seller said that the markets regulator chairperson's response includes "several important admissions and raises numerous new critical questions". 

(Editing by Seban Scaria seban.scaria@lseg.com)