[ejstronge]

The grandparent is describing a separate issue - note that not all hospitals will serve Medicare-receiving patients beyond their federal requirements.

Insurers negotiate reimbursement rates with hospitals, with both parties being able to leverage their size/social cachet to extract favorable terms. This contributes to the availability of certain hospital chains in the preferred networks vs. the non-preferred networks of particular insurers.

[chimeracoder]

It's actually the same issue - the way the contracts are structured, insurers agree to pay X% of what Medicare charges, where X is typically something like 200% or 300%.