Judges heard Elizabeth Holmes' fraud appeal.
Judges heard an appeal from Theranos founder Elizabeth Holmes against her conviction for cheating investors in her blood-testing company.
An appeal was also filed in San Francisco federal court on Tuesday for the startup's president, Ramesh "Sunny" Balwani, who is also Holmes' former partner.
The two were tried separately in 2022, and both earned prison sentences for their roles in the Silicon Valley swindle.
Holmes' lawyer told judges that her client thought she was telling the truth when she promoted blood-testing equipment to attract investment.
Theranos was formed after Holmes dropped out of Stanford University and is now valued at $9 billion (£7 billion).
The entrepreneur was believed to be the world's youngest self-made billionaire, having received financing from high-profile players such as Rupert Murdoch.
Things unraveled in 2018 when, investigations found that the technology did not function. Holmes and Balwani were accused of concealing poor results from Theranos devices, which were advertised as capable of testing for hundreds of ailments with only a few drops of blood.
The company's demise was recorded in a television series, an HBO documentary, and a podcast.
Holmes was imprisoned for more than 11 years over the incident and is currently spending time in a Texas prison. Balwani received a sentence of more than twelve years.
Neither of them attended Tuesday's hearing, during which Holmes' attorney questioned a former Theranos employee's testimony and argued that Holmes should have had a better chance to call into question another key prosecution witness.
The lawyer described the case, which ended in a split verdict, as being close. The prosecution contested this, describing the evidence against Holmes as overwhelming.
Meanwhile, Balwani's lawyer said that prosecutors included information that went outside the scope of his client's 2018 indictment.
According to US media, the trio of judges considering the case provided few clues as to when or how they may rule, other than to say that the non-contested evidence was substantial.
