But a day before that, US-based investment firm Hindenburg Research published a report accusing the Adani group of decades of "brazen" stock manipulation and accounting fraud.Hindenburg specialises in "short-selling" - betting against a company's share price in the expectation that it will fall.The Adani Group responded by calling the report "a malicious combination of selective misinformation and stale, baseless and discredited allegations", but that wasn't enough to stem investor fears.