Adani Group Chairman and founder Gautam Adani addresses a gathering during the concluding ceremony of the Vibrant Gujarat Summit in Gandhinagar in the western Indian state of Gujarat January 12, 2015.
New Delhi CNN  — 

Gautam Adani looks set to cede his position as Asia’s richest man to another Indian billionaire as shares in his business empire continue to plunge following fraud allegations leveled by an American short seller.

In an investigation published last Tuesday, Hindenburg Research accused Adani’s ports-to-power group of “brazen stock manipulation and accounting fraud scheme over the course of decades.”

Adani Group denounced the report as “baseless” and “malicious,” and has said it is considering legal action, but the market reaction has been brutal and relentless.

The conglomerate, which has seven listed companies, has lost more than $90 billion in market value in the week since Hindenburg published its report.

That market rout has wiped nearly $40 billion off Adani’s personal fortune. A week ago he was the fourth-richest person in the world. Now he ranks 10th on the Bloomberg Billionaires Index and looks set to be overtaken by Mukesh Ambani, India’s energy-to-telecom entrepreneur, as Asia’s richest man. Bloomberg’s index is updated at the close of every trading day in New York.

Forbes’ real-time ranking of billionaires already has Ambani, who controls Reliance Industries, above Adani. Ambani’s net worth stands at $83 billion, making him the world’s ninth-richest person, while Adani’s wealth is estimated at about $75 billion, according to Forbes.

The turmoil comes despite a brief respite Tuesday for Adani when his flagship firm, Adani Enterprises, managed to issue new shares worth $2.5 billion. The capital-raising exercise was touted as India’s biggest ever public offering by a listed company. After a tepid start, the offer was fully subscribed shortly before the close of trading in Mumbai.

But interest from retail investors was muted, and the market crash resumed Wednesday. Shares in Adani Enterprises closed down nearly 30% on Wednesday, while Adani Ports plunged almost 20%.

Indian market regulators have not yet commented on the dramatic events of the past week. But the Securities and Exchange Board of India (SEBI) is examining the stock price falls and is also looking into any possible irregularities in Tuesday’s share sale, Reuters reported Wednesday, citing a source with direct knowledge of the matter.

At the peak of his wealth last year, Adani was the world’s second-richest person, ahead of Jeff Bezos. That was the first time a person from Asia had ranked so highly on the Bloomberg list, long dominated by white tech entrepreneurs.