Ken Griffin is seeking financial damages over a data breach, claiming the IRS didn't protect his information.
Carlos Kepke, 83, died of a self-inflicted gunshot wound to the head the day before his trial was scheduled to start.
Carlos Kepke had been charged with helping private equity billionaire Robert F. Smith evade taxes.
The popular method of tax avoidance involves the 2010 Foreign Account Tax Compliance Act, or FATCA.
Oracle's chairman testified in a lawsuit that he didn't call the shots at the company he co-founded.
IRS says Carlos Kepke is one of the enablers who has help Americans hide untaxed billions abroad.
Allianz has agreed to pay $6 billion to clean up the mess.
Authorities say Greg Tournant sold lies to investors that cost customers, and now Allianz, billions.
Billionaire Robert Brockman is facing the largest U.S. tax-evasion case against an individual.
The software mogul is using tax havens and property transfers to family, said the Justice Department.