Mumbai, 21/11: Indian billionaire and business tycoon Gautam Adani’s net worth dropped by more than $10 billion, almost 15 per cent, to $59.4 billion after a US court issued an arrest warrant on bribery allegations..Multiple counts of fraud – which US authorities say involved a firm that was listed in New York and affected American investors – were levelled against Adani, who is one of the world’s richest people, as well as seven other defendants.