U.S. · ACH payments
ACH notification of change codes, C01 to C07.
Pick a code to see what it corrects and when a bank uses it. The six codes below are the ones federal agencies process.
A Notification of Change (NOC, Nacha SEC code COR) is how a bank tells the sender to fix account information in an ACH entry. The federal government processes six change codes: C01 incorrect account number, C02 incorrect RTN, C03 incorrect RTN and account number, C05 incorrect transaction code, C06 incorrect account number and transaction code, and C07 incorrect RTN, account number and transaction code. Federal agencies will not process other codes.
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The six codes
| Code | Meaning | When to use |
|---|---|---|
| C01 | Incorrect account number | Correct data entry errors in the account information. Issue a new number to an existing account. Modify the account numbering system (for example to drop a branch code). |
| C02 | Incorrect RTN | Accommodate a merger or system consolidation. Change the RTN to the preferred RTN for the financial institution. |
| C03 | Incorrect RTN and incorrect account number | Accommodate a merger or system consolidation. |
| C05 | Incorrect transaction code | Change from checking to savings or savings to checking. |
| C06 | Incorrect account number and incorrect transaction code | Correct a data entry error in the account information and change from checking to savings or savings to checking. Issue a new account number and transaction code. |
| C07 | Incorrect RTN, incorrect account number and incorrect transaction code | Accommodate a merger or system consolidation. |
Descriptions follow the Treasury Fiscal Service Green Book chapter on Notification of Change, which states these are the only codes the federal disbursing systems can process.
Transaction codes allowed in a change
The Green Book says the only transaction codes the federal government recognizes for these entries are 22 (credit) and 27 (debit) for checking (demand) accounts, 32 (credit) and 37 (debit) for savings, and 42 (credit) for general ledger. For C05 and C06, the corrected transaction code is one of those.
How a federal NOC is handled
- NOC is the name for the Nacha SEC code COR, used by a financial institution to tell a federal agency to correct account information in an entry the agency sent through the ACH.
- It applies to recurring federal payments such as Social Security, Supplemental Security Income, Veterans Affairs benefits, Civil service retirement, Railroad Retirement, federal salary, TreasuryDirect and vendor payments.
- Changes are generally processed for the next ACH transaction, and may take two payment cycles. If the agency does not respond in two cycles, check the formatting (including the correct original RDFI routing number) and contact Fiscal Service.
- The claim number (individual ID) must be reproduced exactly, with all spaces, hyphens, prefixes, suffixes and leading or trailing zeros.
Worked example
A recipient moves their Social Security deposit from checking to savings at the same bank. The bank sends a COR with change code C05 and the new transaction code 32 (savings credit). If the account number also changed, the code is C06. If the bank merged and its routing number changed, the code is C02.
What this page does not cover
Nacha defines additional change codes in its Operating Rules, which were not read for this page. Private-sector senders should use the current Nacha Operating Rules and their bank's guidance. Name and address changes for federal payments are made by contacting the paying agency, not by NOC.
Sources
Primary sources opened and checked on November 2, 2026. This page has no affiliation with any agency; confirm with the agency before you rely on an amount or date.
Frequently asked questions
What is an ACH Notification of Change?
A message, with Nacha SEC code COR, from a financial institution telling the sender to correct account information in an ACH entry.
Which NOC codes do federal agencies accept?
C01, C02, C03, C05, C06 and C07. Federal agencies will not process any others.
What does C01 mean?
Incorrect account number: used to correct data entry errors, issue a new number to an existing account, or modify the account numbering system.
What does C05 mean?
Incorrect transaction code: used to change from checking to savings or savings to checking.
How long does a federal NOC take?
Generally the next ACH transaction, though some can take two payment cycles.
Reference only
This page reproduces the federal code descriptions as published by Treasury and does not replace the Nacha Operating Rules. Everything runs in your browser; nothing you enter is sent anywhere.