104,000,000

Bradley Birkenfeld was found guilty of tax evasion, and spent 31 months in prison.  However, he provided the IRS with information on how people can evade taxes, helping the government catch other evaders, so Birkenfeld was awarded $104 million dollars for whistle blowing.

for more information:  Whistleblower imprisoned for tax fraud gets $104 million from IRS for helping expose cheating