A small Ahmedabad-based chartered accountancy firm, whose appointment was questioned by a US short seller in its scathing report against the conglomerate run by billionaire Gautam Adani, has resigned due to “pre-occupation”, Adani Total Gas Ltd said. Hindenburg Research in its January 24 report that levelled allegations of fraud, stock manipulation and money laundering against the Adani group, had also raised the issue of the size and capability of the firms auditing the conglomerate. Adani group has repeatedly denied all allegations.