ACH Forms

C01 ACH NOC code: Incorrect DFI Account Number

What C01 means

The account number you used is wrong or formatted wrongly. The receiving bank posted the payment and is sending you the correct account number.

Checked against 5 sources. Last reviewed .

C01 key facts

Official title Incorrect DFI Account Number
Status In use
What the notice gives you The correct account number.
Used with All payment types.
Sent by Receiving bank (RDFI), within 2 banking days of the payment settling
Your deadline Within six banking days of receiving the notice, or before you send another payment to that account, whichever is later. For a one-time payment you may choose whether to act on it.
Was the payment returned? No. A Notification of Change means the payment was posted.

Update your records

  1. Replace the account number you hold for this person or business with the one in the notice.
  2. Use the new number on every future payment. The receiving bank stands behind the corrected number it sends you.
  3. Change the details everywhere they are stored: payroll, accounts payable, and saved templates at your bank.

Questions and answers

Is C01 an ACH return code?

No. C01 is a change code on a Notification of Change (NOC). The payment was not returned. It went through, and the bank is telling you to fix the account number before the next one. Return codes start with R.

What happens if I ignore a C01 notice?

You would be breaking the Nacha rules, which ask you to make the change within six banking days or before the next payment, whichever is later. Banks warn that ignoring these notices can lead to fines or fees that are passed on to you.

How long do I have to act on a C01 notice?

Within six banking days of receiving the notice, or before you send another payment to that account, whichever is later. For a one-time payment you may choose whether to act on it. The receiving bank sends the notice within two banking days of the payment settling, and your bank passes it to you within two banking days after that.

Sources

  1. Minor Rules Topics, effective June 21, 2024 (Originator action on Notification of Change), Nacha
  2. Green Book, chapter 6: Notification of Change, US Treasury, Bureau of the Fiscal Service
  3. FedACH Notification of Change exception form, Federal Reserve Financial Services
  4. 2026 Corporate User ACH Quick Reference Cards, EPCOR
  5. ACH Return, NOC and Transaction Codes, Commerce Bank

Last reviewed . How we check our information. Report a mistake on this page.

General information, not legal or financial advice. Rules change and banks set their own requirements. Check with your bank before you act. ACH Forms is not affiliated with Nacha.