The US Supreme Court has rejected an appeal from former WorldCom CEO Bernie Ebbers on his 25 year sentence for one of the world's biggest accounting frauds.

According to The Register, Ebbers argued that the trial judge in his case erred by refusing to grant immunity to several prospective defence witnesses who would have presented evidence clearing him of wrongdoing. His attorneys also said the judge wrongly instructed the jury that Ebbers could be convicted based on "conscious avoidance".   
In 2005, a federal jury convicted Ebbers of nine counts of conspiracy, securities fraud and other crimes that led to WorldCom's bankruptcy three years earlier. An appeals court upheld that ruling and rejected arguments similar to those made by Ebbers to the Supreme Court.
The WorldCom case ranks alongside Enron and Tyco as one of the most high-profile corporate fraud prosecutions in US history.
The 65-year-old Ebbers will be due for release from prison in 2028.
WorldCom emerged from bankruptcy as MCI, which was later acquired by Verizon.