The 2nd U.S. Circuit Court of Appeals in Manhattan issued a written ruling upholding the 2004 convictions of Stewart and former stockbroker Peter Bacanovic for lying about why Stewart sold nearly 4,000 shares of ImClone Systems in 2001.
The appeals court said that none of the numerous grounds upon which Stewart and Bacanovic challenged their convictions provided a basis to disturb the jury's verdict.
Stewart served five months in prison and five months of home detention, finishing her sentence last summer. Bacanovic completed his five month prison sentence last year as well.
Friday's ruling "has almost no practical effect," says CBS News legal analyst Andrew Cohen.
"Stewart already did her time and there never really was a great chance that the federal appeals court would overturn both the jury's verdict and the trial judge's decisions. So this sews up this case on another losing note for Stewart," Cohen said.
Stewart had sold her shares in ImClone Systems just before it took a dive on a negative government report about the company.
In a 74-page ruling, the appeals court rejected arguments by lawyers for both defendants that they were prejudiced by language and evidence at their five-week trial concerning insider trading, with which neither of them was charged.
The appeals court said the trial judge properly described the law to the jurors so that they knew they could not convict the defendants for a crime that was never charged.
The court also rejected a defense argument that the judge should have permitted them to call a securities law expert to testify about the legality of Stewart's stock trades.
The appeals court said the expert's opinion that Stewart's conduct did not violate the securities laws would have increased the potential for confusion among jurors because facts concerning insider trading charges were not relevant to the actual charges.