Theranos founder Elizabeth Holmes has been found guilty of defrauding investors after a months-long landmark trial in California.
Prosecutors said Holmes knowingly lied about technology that she says could detect disease with a few drops of blood.
Jurors found Holmes guilty of four counts, including conspiracy to commit fraud against investors and three counts of wire fraud.
She denied the charges, which carry a maximum prison sentence of 20 years each.
Holmes was not detained, a sentencing date has not yet been confirmed and an additional hearing has been scheduled next week.
She faced 11 charges in total and was found not guilty of four charges related to defrauding the public.
The split verdict came after the judge said the jury, after deliberating for seven days, could render a partial verdict after failing to reach consensus on three other charges.
Theranos, at one time valued at $ 9bn (£ 6.5bn), was once a Silicon Valley darling.
The firm promised it would revolutionize the healthcare industry, but its claims began to unravel in 2015 after a Wall Street Journal investigation reported that its core blood test technology was down.
During nearly four months at trial, the jury of eight men and four women was presented with two completely different accounts of the former self-made billionaire whose downfall rocked Silicon Valley.
After calling about 30 witnesses, the prosecution tried to show that Ms. Holmes knew that the product she was selling to investors was a sham, but she remained committed to the success of the company.
At trial, several laboratory directors testified that they told Holmes about the flaws in Theranos’ technology, but were instructed to downplay her concerns. At the same time, they said, Holmes told investors that the technology was working as planned.
Holmes “chose fraud over business failure. She chose to be dishonest with investors and patients,” prosecutor Jeff Schenk said in closing arguments. “That choice was not only insensitive, it was criminal.”
The defense fought back with descriptions of a dedicated and determined businesswoman, making waves in a male-dominated industry.
Testifying in her own defense, Holmes acknowledged the mistakes in Theranos’ operation, but maintained that she never knowingly defrauded patients or investors.
The defense also blamed Ramesh “Sunny” Balwani, Holmes’ former business partner and longtime boyfriend.
Holmes has accused Balwani, 19 years her senior, of emotional and sexual abuse, allegations he denies. Their decade-long relationship came to an end around the same time that he stepped down as CEO in May 2016. He faces a separate trial next month.
Holmes founded Theranos when she was a teenager, shortly after dropping out of chemical engineering at Stanford University.
He was able to raise more than $ 900 million from billionaires like media mogul Rupert Murdoch and tech mogul Larry Ellison.
The firm officially ceased operations in 2018 following the scandal.