Black, 63, is serving a 6 1/2-year prison sentence in Florida after being convicted last summer and the three-judge panel of 7th U.S. Circuit Court of Appeals unanimously upheld the conviction, the Chicago Sun-Times reported.

In a 16-page ruling, the judges rejected all claims by Black and three other Hollinger International executives convicted of defrauding the company, now known as the Sun-Times Media Group, the Chicago Sun-Times reported.

Defense attorney Andrew Frey told a Canwest New Service correspondent a U.S. Supreme Court appeal wasn't out of the question.

"We're very disappointed and we're looking at what next steps make sense," Frey said.

Before charges were laid, Black renounced his Canadian citizenship so he could assume a peerage in Britain's House of Lords, which was revoked on his conviction.