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N664 Remark Code: Adjusted Under a Legal Settlement

N664 means the payer adjusted the claim based on a legal settlement. The amount paid, or the fact that nothing more will be paid, was determined by a settlement agreement, typically in a workers' compensation, auto, or liability case.

Quick facts

Code
N664 (RARC N664)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The carrier considers the amount beyond what the settlement provides as not payable by it. Whether the patient or another party can be billed depends on the settlement terms and applicable law.
  • PR (Patient Responsibility): Some carriers indicate the claimant is responsible, for example when the settlement gave medical funds to the claimant. Confirm the terms first.
Official description
Adjusted based on a legal settlement.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N664 means

In injury cases, the parties sometimes settle: a workers’ compensation claim closed by a compromise, an auto claim resolved between the injured person and an insurer, or a liability lawsuit that ends in an agreement. Settlements often decide what happens to medical bills, whether they get paid in full, paid at a reduced amount, or become the claimant’s responsibility from settlement funds.

N664 tells you the carrier applied such a settlement to your claim. It is used mainly by workers’ compensation, auto, and liability carriers, and the specifics depend heavily on the settlement terms and the state.

Situations where you might see it

  • A workers’ compensation case settled and future medical benefits were closed or given to the worker as a lump sum.
  • A liability claim settled with a set amount allocated to outstanding medical bills.
  • A carrier paid a negotiated amount on outstanding bills as part of the settlement.
  • A service was billed after the settlement date for care the carrier says it no longer covers.

What to do

  1. Contact the adjuster and ask for the settlement date and the terms that affect medical bills.
  2. Check whether your bills were included and whether you agreed to any reduction.
  3. Identify the next source of payment: a set-aside account, the claimant, the patient’s health plan, or a lien against the settlement, depending on the case and state law.
  4. Dispute the adjustment if your services predate the settlement and weren’t addressed in it.
  5. Involve the patient’s attorney where one represents the patient, since settlement funds often pass through them.

How to prevent it

For open injury cases, keep in touch with the adjuster and any attorney, and submit outstanding bills promptly so they’re known before the case settles. Where state law allows, some providers file notices or liens to protect their balances.

Codes that may appear with N664

  • CO-215 (Based on subrogation of a third party settlement): Adjustment based on subrogation of a third-party settlement.
  • PR-201 (Patient is responsible for amount of this claim/service through 'set aside arrangement' or other agreement. (Use only with Group Code PR)): The patient is responsible through a set-aside arrangement or other agreement.
  • N585 (Benefits are no longer available based on a final injury settlement.): Benefits are no longer available because of a final injury settlement.
  • N663 (Adjusted based on an agreed amount.): An agreed amount between provider and payer, not a legal settlement.
  • N722 (Patient must use Workers' Compensation Set-Aside (WCSA) funds to pay for the medical service or item.): The patient must use workers' compensation set-aside funds for the service.
  • N611 (Claim in litigation.): The claim is in litigation.

N664 FAQ

Who was party to the settlement?

Usually the injured person and the carrier or liable party, sometimes with the provider included. Ask the adjuster whether your bills were part of it.

Can I bill the patient after a settlement?

It depends on the settlement terms and state law. Some settlements set aside money for medical bills; others close future medical benefits. Get the relevant terms before billing.

Can a provider challenge N664?

If the provider wasn't part of the settlement and the services aren't covered by its terms, the provider may be able to dispute the adjustment. The process varies by jurisdiction.