In 2003, Holmes founded and was the chief executive officer (CEO) of Theranos, a now-defunct health technology company that soared in valuation after the company claimed to have revolutionized blood testing by developing methods that could use surprisingly small volumes of blood, such as from a fingerprick.
By 2015, Forbes had named Holmes the youngest and wealthiest self-made female billionaire in America on the basis of a $9-billion valuation of her company.
In the following year, as revelations of potential fraud about Theranos's claims began to surface, Forbes revised its estimate of Holmes's net worth to zero, and Fortune named her in its feature article on "The World's 19 Most Disappointing Leaders".
The credibility of Theranos was attributed in part to Holmes's personal connections and ability to recruit the support of influential people, including Henry Kissinger, George Shultz, Jim Mattis, and Betsy DeVos, all of whom had served or would go on to serve as U.S. presidential cabinet officials
Holmes was in a clandestine romantic relationship with Balwani during most of Theranos's history. Following the collapse of Theranos, she started dating hotel heir Billy Evans, with whom she had a son in 2021.