Theranos founder Elizabeth Holmes and former company president Ramesh "Sunny" Balwani were accused Friday by federal prosecutors of criminally defrauding investors, patients and doctors. Holmes stepped down as the blood-testing company's CEO shortly before the charges were announced, but will remain board chair.

The big picture: The SEC filed civil fraud charges in March, so the criminal complaint isn't terribly surprising. Holmes settled those charges, while Balwani opted to fight them. Per Axios' Dan Primack, this is the "largest alleged fraud ever perpetrated in Silicon Valley."