What does CO-299 mean?

CO-299 is a Contractual Obligation (CO) denial: "The billing provider is not eligible to receive payment for the service billed." The billing provider's enrollment, contract, or credentialing doesn't allow payment for this specific service — a provider-eligibility problem, not a clinical one.

CO · Contractual ObligationCARC 299

Denial Code CO-299

Q: Is CO-299 the patient's responsibility or a provider write-off?

CO-299 carries the CO group code (Contractual Obligation): Provider/contractual responsibility — not billable to the patient while denied. A CO adjustment is the provider's responsibility, not the patient's: balance-billing the patient for a CO amount is a contract (and often compliance) violation. But CO does not automatically mean “write it off.” When the cause is fixable — missing information (CO-16), a modifier problem (CO-4), or NCCI bundling (CO-97) — you correct and resubmit, or appeal with documentation. You only truly write the amount off when it is a final contractual adjustment, such as the fee-schedule difference on CO-45.

The billing provider is not eligible to receive payment for the service billed.

Source: X12 Claim Adjustment Reason Codes (CARC) & Group Codes. Maintained by the D3rx Clinical Billing Team.

What CO-299 means

The billing provider's enrollment, contract, or credentialing doesn't allow payment for this specific service — a provider-eligibility problem, not a clinical one.

Why CO-299 happens

The billing provider isn't enrolled or contracted with the payer for this service type
A group NPI was used where the practice isn't contracted for the service
The provider's taxonomy code doesn't match the service billed
An enrollment gap or termination on the date of service

What to do when you get CO-299

1Verify the billing NPI and taxonomy code on the claim are correct for the service
2Confirm the billing provider's enrollment/contract status with the payer for this service type
3Resolve any enrollment or credentialing gap through provider relations/enrollment
4Resubmit the claim once the eligibility issue is corrected

Got this denial right now?

Fix & resubmit: see the CO-299 correction steps

See CO-299 correction steps Ask D3 about CO-299

CO-299 clears with a corrected claim, not an appeal. Ask D3 walks you through the exact fix — free, no signup.

CO group code: who absorbs the charge

Contractual Obligation — Provider/contractual responsibility — not billable to the patient while denied.

A CO adjustment is the provider's responsibility, not the patient's: balance-billing the patient for a CO amount is a contract (and often compliance) violation. But CO does not automatically mean “write it off.” When the cause is fixable — missing information (CO-16), a modifier problem (CO-4), or NCCI bundling (CO-97) — you correct and resubmit, or appeal with documentation. You only truly write the amount off when it is a final contractual adjustment, such as the fee-schedule difference on CO-45.

Appeal, correct, or write off CO-299?

CO-299 is a corrected-claim or enrollment fix — make sure the right billing NPI/taxonomy is on the claim and that the provider is enrolled for the service, then resubmit. Appeal with proof of enrollment only if the provider WAS eligible and contracted on the date of service and the payer's record is wrong.

Timing & deadlines

Resubmit within the timely-filing limit (Medicare 12 months from date of service; commercial ~90-180 days). Enrollment corrections can be slow, so begin them immediately to protect the filing window.

Example

A newly hired provider's claims are billed under the group before their payer enrollment links to the group. The payer returns CO-299 (billing provider not eligible). Completing the enrollment linkage and resubmitting resolves it.

Prevent CO-299 going forward

Confirm provider enrollment/credentialing is active before billing under them
Match billing NPI and taxonomy to the service and contract
Track enrollment effective dates for new and locum providers
Hold claims for not-yet-enrolled providers rather than letting them deny

Code families most affected

Claims for newly enrolling or credentialing providers
Group billing where the service isn't contracted
Service-type-restricted provider contracts

Related codes

Denial codes you'll often see alongside CO-299

CO-16 CO-109 CO-242

Payer notes

CO-299 targets the BILLING provider's eligibility to be paid (distinct from CO-183's referring-provider eligibility). It is typically an enrollment/contract/credentialing fix, not a coding change.

Fix this CO-299 denial the right way

CO-299 is resolved with a corrected claim, not an appeal. Ask D3 gives you the exact correction steps — free, backed by CMS, Medicare, and major-payer data.

See CO-299 correction steps Ask D3 about CO-299 All denial codes

Medical billing disclaimer

CARC/RARC definitions are the standardized X12 set; group-code semantics follow the X12 Claim Adjustment Group Code standard. Filing and appeal windows vary by payer — the standard anchors shown (Medicare redetermination 120 days from the remittance; Medicare timely filing 12 months from date of service; most commercial payers ~90-180 days) are general references, not a guarantee for any specific plan. Always confirm the rule in the payer's provider manual before acting. D3rx is not responsible for claim outcomes.