Mr Rich fled the US for Switzerland in 1983. He was then facing charges of racketeering, illegal trading and evading a tax bill of $48m.His ex-wife, Denise Rich, is a songwriter and New York socialite. It was the disclosure of her large donations to the Democratic Party that led Republicans to question Mr Clinton's decision to pardon Mr Rich.
Mr Rich made his money in oil, and was once a regular at OPEC oil conferences.
One of the charges brought against him before he fled the US, was trading oil with Iran - a country which at that time was considered an enemy state.