Holmes rose to Silicon Valley fame after founding Theranos, a blood-testing startup, in 2003.
Prosecutors say she swindled investors over the next decade, including media mogul Rupert Murdoch, on claims that the company's small machines could run a range of tests with just a few drops of blood.
Investigations by the Wall Street Journal later debunked these claims, and Holmes was indicted in 2018 alongside former Theranos COO Ramesh Balwani.
On Monday she was acquitted on three counts of defrauding patients who paid for tests from Theranos and a related conspiracy charge, while the jury could not reach a decision on three other counts related to individual investors.
Testifying in her own defense at trial, Holmes had said she never meant to deceive anyone and that Theranos' lab directors were in charge of test quality.
She was also charged with misleading patients about the tests' accuracy but was acquitted of those charges.
Holmes, who is likely to appeal, faces up to 80 years in prison, but will likely get a much lower sentence.
