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N656 Remark Code: Late-Payment Interest Included

N656 means the payer is paying interest on the claim because it paid benefits later than the time allowed by law, such as a state prompt-pay statute. It is good news: extra money, not a reduction.

Quick facts

Code
N656 (RARC N656)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • OA (Other Adjustment): Some payers report interest in an other-adjustment context. The interest increases the payment and is not a patient balance.
  • CO (Contractual Obligation): Other payers report the interest alongside contractual adjustments. Either way, it is money owed to the provider, not the patient.
Official description
An interest payment is being made because benefits are being paid outside the statutory requirement.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N656 means

Many states have prompt-pay laws that require insurers to pay clean claims within a set time, and federal programs have their own timeliness rules. When a payer misses the deadline, the law often requires it to add interest. N656 identifies that interest on the remittance.

The remark doesn’t signal a problem with your claim. It signals a problem with how fast the payer processed it, and the payer is paying for the delay.

Where the interest shows up

Payers report interest in different ways. You may see it as a separate interest amount on the claim, as a negative adjustment that increases the payment, or as a line in the provider-level section of the remittance. The paid amount may therefore be higher than the allowed amount, or even higher than your billed charges.

What to do

  1. Post the interest separately from the claim payment so it doesn’t distort the claim balance or reduce what the patient owes.
  2. Check the amount against the statute or regulation that applies, using the date the payer received the clean claim and the date it paid.
  3. Keep the remittance, since interest income may need to be accounted for differently from service revenue.
  4. Follow up if you believe the interest was under-calculated, citing the rule and your dates.

Why it’s worth tracking

Payers that pay interest frequently are, by definition, paying late. Tracking N656 by payer gives you evidence of slow processing, which is useful in contract talks or when raising concerns with a regulator. An ERA Analyzer that trends payment timing and interest by payer makes that pattern easy to see.

Claims that miss prompt-pay deadlines are usually clean claims. If a payer delays by asking for more information, the deadline rules can change, depending on the state.

Codes that may appear with N656

  • CO-94 (Processed in Excess of charges.): Processed in excess of charges, which can happen when interest pushes the payment above the billed amount.
  • PR-85 (Patient Interest Adjustment (Use Only Group code PR)): Patient interest adjustment, used with group PR, which is a different kind of interest.
  • CO-225 (Penalty or Interest Payment by Payer (Only used for plan to plan encounter reporting within the 837)): Penalty or interest payment by a payer, limited to plan-to-plan encounter reporting.
  • N663 (Adjusted based on an agreed amount.): An adjustment based on an agreed amount, another non-fee-schedule explanation.

N656 FAQ

How do I post an interest payment?

Post it as interest income rather than as payment against the patient's charges, so the claim balance and patient responsibility stay accurate. Follow your accountant's guidance on the account used.

How is the interest calculated?

By the rules of the applicable statute or regulation, which set the deadline and the rate. These vary by state and by program, so compare the amount to the rule that governs the claim.

What if a late claim did not include interest?

If a prompt-pay law applies and the payer paid after the deadline without interest, you can ask the payer to calculate and pay it, and some states let you complain to the insurance regulator.