Currently studying this. It depends on your payer mix. Medicare and Medicaid never negotiate. Insurers will negotiate reimbursement rate to docs/hospitals, depending on the situation. If one insurance company dominates the market, they won’t negotiate. Why would they? They insure 80% of a city, what can a hospital do? Refuse patients on that plan? Then they lose access to 80% of potential revenues

Edit: this is an oversimplification, but I’m not here to write an entire essay on reimbursement mechanisms. Fee for service is increasingly rare, but the same logic applies. There is another side to the argument of course. If you’re the best hospital in the area, you have leverage over the insurance company. It all depends on who you are and how popular you are, both for a hospital system and an insurer. Just like any company negotiating buying a wholesale good from another company.