Adani Group has published a 413-page rebuttal of fraud allegations by Hindenburg Research, likening the US investment firm’s report to an attack on India amid mounting financial pressure on the coal conglomerate. The lengthy response was an attempt to soothe investor concerns and stir nationalist fervour as Adani attempts to complete a US$2.5bn share sale, one of India’s largest ever fundraising campaigns, designed to finance capital expenditure and reduce debt. However, most Adani Group shares fell sharply in India during Monday’s trading session as rebuttal failed to pacify investors, deepening a market rout that has now led to losses of $65bn in the group’s stock values. Adani Transmission, Adani Total Gas, Adani Green Energy, Adani Power and Adani Wilmar fell between 5% and 20% in Monday trade. Adani’s response (PDF) was published several hours before the Indian markets reopened on Monday, after a near US$50bn plunge in the overall value of the conglomerate’s entities in wild trading last week. “This is not merely an unwarranted attack on any specific company but a calculated attack on India, the independence, integrity and quality of Indian institutions, and the growth story and ambition of India,” the Adani response said. Sign up for Guardian Australia’s free morning and afternoon email newsletters for your daily news roundup “The allegations and insinuations, which were presented as fact, spread like fire, wiping off a large amount of investor wealth and netting a profit for Hindenburg. The net result is that public investors lose and Hindenburg makes a windfall gain.” Hindenburg’s report claimed that the Adani empire was the “biggest con in corporate history” engaged in a “brazen stock manipulation and accounting fraud scheme”. It also accused Adani of loading companies with debt that has put the entire group on a “precarious financial footing”. The US company cited a series of transactions tied to Adani’s Carmichael mine and rail operations in Queensland that it alleged may have allowed Adani to avoid disclosing to investors that some of the Australian assets had lost value – a charge the Indian conglomerate disputes. Adani said in its published response that the transactions were compliant and at arm’s length terms. The short seller’s allegations have wiped billions of dollars of value from the sprawling empire of Gautam Adani, who was the world’s third-richest man until more than US$22bn was erased from his personal net worth in the fallout from the report. The Indian industrialist is now the world’s seventh-richest, according to Forbes. The Adani companies and its billionaire chairman are seen as being close to Indian Prime Minister Narendra Modi. The report has weighed on the broader Indian market, denting otherwise strong recent returns for emerging markets. Hindenburg disclosed it took a short position in Adani companies before it published its report. Activist funds like Hindenburg use financial instruments to profit from falling share prices in the companies they target, which they believe are heavily overvalued and have poor or fraudulent business practices. Named after the 1937 airship disaster, Hindenburg looks for stocks that could crash. Adani’s lengthy statement contains responses to questions raised by Hindenburg, as well as supporting documents such as court rulings and extracts from company reports. The response also questions the motives, transparency and legality of the Nate Anderson-founded activist fund’s report. Hindenburg promptly responded to the Adani statement as trading got underway in Asia on Monday, denying any wrongdoing. It also claimed that the Indian conglomerate was using patriotic ties to avoid addressing serious issues. The US company said fraud cannot be “obfuscated by nationalism or a bloated response”. Part of the dispute centres on Hindenburg allegations that the Adani companies engage in widespread and undisclosed related-party transactions, where as the conglomerate says all such dealings are properly accounted for. Notably for investors, Adani said the amount of borrowed money its companies use are in line with industry benchmarks. Adani accused the US company of having contempt for Indian regulators and the judiciary by highlighting old allegations that Adani said had since been “judicially determined to be false”. This included allegations that Samir Vora, the executive director of Adani Australia, was a key figure in a diamond trading scam designed to defraud the Indian government. The matter was closed and dismissed, Adani said. The high stakes tit-for-tat came after Hindenburg dared Adani to take it to court given it would open the coal conglomerate to further scrutiny. The Greens’ federal industry spokesperson, Penny Allman-Payne, has said the Hindenburg report should prompt Queensland’s Labor government to question whether Adani should operate in Australia. Located in Queensland’s coal-rich Galilee Basin, the Adani project exported its first coal in late 2021, drawing widespread opposition due to the fossil fuel’s significant contribution to greenhouse gas emissions.