Last reviewed: · Curated by Ohmyfin Organisation editorial.
AC01 (IncorrectAccountNumber) is an ISO 20022 ExternalReturnReason code used in pacs.002 / MT103 STP rejection messages on the SWIFT network. The beneficiary account number is incorrect or does not exist.
Details
Why it happens: A typo in the IBAN, an old account number that has been closed, or wrong country routing.
How to fix it: Confirm the IBAN/account number with the beneficiary, then re-issue the payment with the corrected details.
When a bank rejects a SWIFT payment with AC01, you usually receive the code along with an MT103-STP, MT n96, or pacs.002 message. Your bank may relay the code to you with a plain-English explanation. If they don't, paste your UETR into the Ohmyfin tracker — the rejection status will show in the SWIFT GPI feed.
AC01 is part of the global ExternalReturnReason1Code code set maintained by ISO 20022. The same code is used by SWIFT, SEPA, FedNow, TARGET2 and most modern payment rails worldwide.
Key facts
Code: AC01
Full name: IncorrectAccountNumber
Standard: ISO 20022 ExternalReturnReason1Code
Carried in: pacs.002, MT103 STP rejection, MT n96
Visible on Ohmyfin: yes — paste your UETR to see the full rejection trail
Frequently asked questions
What does SWIFT reject code AC01 mean?
The beneficiary account number is incorrect or does not exist.
How do I fix a AC01 rejection?
Confirm the IBAN/account number with the beneficiary, then re-issue the payment with the corrected details.
Will I get my money back after a AC01 rejection?
Yes. SWIFT rejections automatically return the funds to the originator's account, usually within 1–5 business days. Some banks credit immediately; others wait for the actual return wire.
Can I re-send the same payment after AC01?
Yes — once you fix the underlying issue, you can re-send with a new UETR. Do NOT re-send with the same UETR; that triggers AM05 (Duplication).
Related — more from swift reject reason codes and beyond
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