EOB denial code · CO group
CO-29: Timely Filing Denied — Meaning & How to Appeal
CO-29 means the provider submitted the claim after the insurer's filing deadline (typically 90–365 days from the date of service). For in-network care this is a provider-side timing issue — the patient is rarely at fault, but the insurer may still ask why the claim was late. A single reconsideration letter correcting the record often gets a CO-29 reprocessed.
What “CO-29” means on your EOB
The time limit for filing has expired.
Who pays? CO — Contractual Obligation
CO (contractual) — though consequences can leak to the patient: if the provider can't collect, some states allow billing the patient after a timely-filing denial. Act quickly.
What to do next: A CO-29 appeal succeeds most often when the delay wasn't the patient's fault and the provider documents it: "billing system error," "reprocessed X-ray records," or "waiting on another payer." Many payers grant one courtesy reconsideration. If you're denied after that, file a complaint with your state's insurance department.
Why this denial happens
- Provider billing department submitted late (the most common cause).
- Claim was rejected for a minor error, then resubmitted after the deadline.
- Paper claims stuck in processing for months.
- Patient didn't give the provider their insurance card until after the deadline.
What to do now
- Ask your provider for the exact claim submission date — if they submitted on time, the payer's date is wrong.
- If the provider was late, ask their billing manager to write a brief reconsideration letter citing the reason and resubmit.
- If you (or a data-entry delay) caused the lateness, appeal anyway and explain — payers routinely grant one courtesy reconsideration.
- If appeals fail and the provider bills you, compare against your state's rules: many states cap patient liability when the provider's own untimely filing caused the denial.
📄 Denied a claim? Generate a free appeal letter
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Generate an appeal letter →How long do insurers allow for filing?
Most commercial plans allow 90–180 days; Medicare allows 12 months (365 days) for most services, and some states extend commercial deadlines. Check your plan's timely-filing policy.
Can a late claim be appealed?
Yes. Write to the payer explaining the reason for the lateness and request reconsideration. First-time courtesy reconsiderations are common, especially when the provider — not you — caused the delay.
If the provider filed late, can they bill me?
Not automatically. Your bill is governed by your policy's payment rules and state law. Many states prohibit billing a patient when the provider's own untimely filing caused the denial — check with your state insurance department.