Here's a bit more...
Documents filed in the case showed that in 1993 BCBSM implemented a scheme through which it would collect additional revenue by adding certain mark-ups to hospital claims paid by its self-insured customers. Most of the country’s largest employers self-insure, which means that they are on the hook for medical claims when employees and their dependents get sick or injured. Self-insured companies hire firms like BCBSM to do the paperwork. It is the employer’s money—not the insurance company’s—that is “at risk” in such arrangements.
After suing and getting documentation from BCBSM, attorneys for Hi-Lex were able to show the court that BCBSM marked up hospital claims by as much as 22 percent. BCBSM didn’t disclose the markups, however. As part of the scheme, regardless of the amount BCBSM was required to pay a hospital for a given service, it reported a higher amount to Hi-Lex and pocketed the difference.
https://www.publicintegrity.org/2015/05/11/17317/court-case-shows-how-health-insurers-rip-you-and-your-employer
I can go deeper, show more, or you could do more research down the rabbit hole