Rules vary depending on which insurance initially paid for medical treatment. The Personal Injury Protection portion of the insured’s auto insurance policy is typically the first insurance carrier that pays for medical treatment, but not always. If injured while working, workers’ compensation will pay for medical treatment. If not PIP or workers’ compensation, the insured’s medical insurance, Medicare, or Medicaid may pay for medical treatment. In most cases, a portion is repaid through subrogation. The amount that must be repaid through subrogation can be negotiated with the insurer that paid for the medical treatment. Depending on the insurer, the amount to be repaid may be negotiated during the settlement process.