ACH Return

What is an ACH return?

An ACH return is an entry that the receiving bank (the RDFI) sends back instead of posting it, along with a reason code that starts with R. The RDFI sends the return to the originating bank (the ODFI), which passes it to the originator that started the payment. It applies to ACH payments, most often debits.

What are the common ACH return reason codes?

Each return carries one code. Nacha's return code table defines them. The ones operations teams see most:

• R01, Insufficient funds: the available balance does not cover the debit.
• R02, Account closed: a previously active account was closed by the customer or the bank.
• R03, No account or unable to locate account: the account number does not match the person named in the entry, or the account does not exist.
• R04, Invalid account number structure: the account number is not valid.
• R05, Unauthorized debit to consumer account using corporate SEC code: a CCD or CTX debit hit a consumer account without the receiver's authorization.
• R07, Authorization revoked by customer: the receiver withdrew the authorization given to the originator.
• R10, Customer advises originator is not known to receiver and/or originator is not authorized to debit the account.
• R29, Corporate customer advises not authorized: a business receiver says a specific entry was not authorized.

Nacha explains the unauthorized return reasons in more detail.

How long does an RDFI have to return an entry?

For unauthorized debits to non-consumer accounts, the return must reach the ODFI by the opening of business on the second banking day after the entry's settlement date. For unauthorized debits to consumer accounts, the window runs to the opening of business on the banking day after the 60th calendar day, and the RDFI needs a Written Statement of Unauthorized Debit from the consumer. Both are on Nacha's page on warranty claims.

What are the ACH return rate thresholds?

Nacha sets three levels for debit returns, described in its risk and enforcement topics:

• Unauthorized return rate: a 0.5% threshold covering R05, R07, R10, R29 and R51.
• Administrative return rate: a 3.0% level covering R02, R03 and R04.
• Overall return rate: a 15.0% level covering all debit returns for any reason, except RCK entries.

Going over a level starts a preliminary inquiry. It is not an automatic rules violation.

Can a returned entry be sent again?

Sometimes. Nacha limits reinitiation to two times, per its rules topics. A debit returned as unauthorized cannot be fixed by sending it again. The originator needs a new authorization first.

How is a return different from a Notification of Change or a reversal?

A return means the RDFI did not post the entry. A Notification of Change (NOC, with codes starting with C) tells the originator that some data in an entry needs correcting, so future entries use the right details. A reversal goes the other way: the originator or ODFI sends it to correct an erroneous entry, and an RDFI can in turn return a reversal that was improperly originated, as Nacha explains. See also ACH returns and NOC handling automation.

Where do AI agents help with ACH returns?

AI agents can classify each return by code, match it to the original entry, track return rates for each originator against the thresholds above, and prepare the checks before a retry and the notice to the originator. Consumer disputes behind unauthorized returns overlap with Regulation E work (see Reg E dispute investigation automation), and matching returns to the ledger is part of bank reconciliation.

A person decides what happens to the originator, such as a hold, a new authorization request or an exit. Keeping the preparer and the approver separate follows segregation of duties, and four-eyes approval is one way to apply it.

Zamp builds AI employees that run back-office work end to end, with approval gates, a Needs Attention queue for items that need a decision and a full audit trail.

Frequently asked questions

What does R01 mean on an ACH return?

R01 means insufficient funds: the available balance did not cover the debit.

What is the difference between R02, R03 and R04?

R02 means the account was closed. R03 means no account or the RDFI cannot locate it. R04 means the account number structure is invalid. All three count toward the 3.0% administrative return rate level.

Which ACH return codes count as unauthorized?

Nacha's 0.5% unauthorized return rate threshold covers R05, R07, R10, R29 and R51. The overall level of 15.0% counts all debit returns except RCK entries.

Can AI agents handle ACH returns on their own?

They can classify returns, match them to original entries, track rates and draft notices. A person decides on action against an originator, and the audit trail should show who approved it.