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M131 Remark Code: Physician Financial Relationship Form

M131 means the payer required a physician financial relationship form and did not receive it. The form discloses financial ties between the referring physician and the entity furnishing the service.

Quick facts

Code
M131 (RARC M131)
Status
Active In use since January 1, 1997; last modified February 28, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The service was not paid pending the required form. The provider supplies it; the patient is not billed.
Official description
Missing physician financial relationship form.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M131 means

Certain services may be paid only when the payer knows whether the referring physician has a financial relationship with the entity that furnished them. Payers collect this information using a physician financial relationship form. M131 tells you the form was required and missing.

This is documentation-driven. The service may be payable once the form is received and reviewed.

Common causes

  • A payer program or review that requires financial relationship disclosure for specific services.
  • A request for the form sent to an outdated address or contact.
  • Staff unaware that the form was part of the payer’s requirements.
  • The form submitted separately without claim identifiers.

How to fix it

  1. Obtain the payer’s form and instructions.
  2. Complete it accurately with your compliance or legal team, based on current arrangements.
  3. Submit it with the claim number and patient identifiers by the payer’s accepted method.
  4. Ask the payer to reprocess the claim, or resubmit if it requires a new claim.

How to prevent it

  • Keep a current, reviewed disclosure of physician financial relationships available for payer requests.
  • Track which payers or services require the form.
  • Route requests to both billing and compliance so they are answered on time.

Enrollment and ownership records also affect claims; see provider enrollment denials.

Codes that may appear with M131

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim lacks information, identified by M131 as the financial relationship form.
  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): Documentation is required before the service can be adjudicated.
  • N239 (Incomplete/invalid physician financial relationship form.): The form was received but was incomplete or invalid.
  • M134 (Performed by a facility/supplier in which the provider has a financial interest.): The service was performed by a facility or supplier in which the provider has a financial interest.

M131 FAQ

Why do payers ask about financial relationships?

Federal self-referral rules restrict certain referrals when a physician has a financial relationship with the entity providing the service. Payers may need disclosure to confirm the claim complies.

What does the form include?

Typically information about ownership, investment, or compensation arrangements between the physician and the entity. The payer's own form sets the exact content.

Does M131 mean I violated a rule?

No. It only means a required form was missing. Whether any arrangement raises compliance issues is a separate question for your compliance advisers.