Companies owned by one of the world’s richest men – multi-billionaire Gautam Adani – and planning some of India’s most ambitious renewable energy and hydrogen projects have seen their stock market values plunge after being caught up in allegations of “brazen fraud”.

Adani Group companies have over the last few days between them lost more than $70bn, according to financial wire reports, putting a massive dent in the wealth of Adani himself, last year valued at more than $100bn and labelled 'Asia's richest man'.

Adani Green Energy suffered a 20% fall on the Mumbai stock market on Monday, the most permitted under the exchanges rules, continuing a rout that began on Friday and swept across the listed companies of the Adani Group.

The fall was sparked by a report from a US research group called Hindenburg ahead of a $2.5bn share issue by its Adani Enterprises unit, with extraordinary claims that the Adani conglomerate had engaged in “brazen stock manipulation and accounting fraud”.

The group apparently rallied enough backers to subscribe the issue but on Wednesday Adani called it off “to protect the interest of its investing community” in the wake of the stock fluctuations.

Adani had on Sunday hit back aggressively, issuing a rebuttal claiming that the Hindenburg report is designed to create a “false market” to enable profits by short-selling and branding it “a calculated attack on India”.

Adani – who made a fortune in commodities trading in the late 1980s – has over the last two years set out Adani Group’s stall to be a leader of India’s energy transition, with plans to amass a 45GW renewable energy portfolio by 2030 and produce the world’s cheapest green H2.

Adani Green has huge ambitions in the solar sector in particular, and in December claimed to have become the world’s largest PV-wind hybrid developer after commissioning a total of 1.4GW.

Its Indian ambitions have included forging a partnership with French oil supermajor TotalEnergies that aims to create “the largest green hydrogen ecosystem in the world”.

Adani’s green expansion plans have run in parallel with those of fellow Indian billionaire Mukesh Ambani’s Reliance Industries, which has made its own series of multi-billion-dollar forays into the energy transition.

Note: Update adds cancellation of share issue despite subscription backing.