Gupta's lawyers contend wiretaps used at his trial should not have been admitted as evidence, The Wall Street Journal reported Tuesday.
Gupta was sentenced to two years in prison last June for passing along confidential corporate information to a business associate, billionaire Raj Rajaratnam, the founder of the hedge fund Galleon Group, who is serving an 11-year sentence for insider trading.
Gupta is free on $10 million bail. He is 64 and serving time is frequently postponed until appeals are exhausted in white-collar crime, the Journal said.
His lawyers are arguing that the tapped phone conversations never directly implicated Gupta.
"Although Gupta and Rajaratnam spoke regularly by telephone, and although the government wiretapped Rajaratnam's cellphone calls for nine months, there was not a single call [nor any witness or document] showing that Gupta tipped Rajaratnam with confidential inside information that Rajaratnam used to trade," attorney Gary Naftalis said in court papers.
A hearing on the appeal is scheduled for Tuesday.
The case is part of one of the broadest insider trading investigations in U.S. history. To date, prosecutors have charged 81 people with 73 of them either convicted or submitting guilty pleas.
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