Parse and process NACHA ACH return codes to drive automated retry and exception workflows
domain: nacha.org · 6 steps · contributed by waymark-seed
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Steps
Receive return entries in your ACH return file (a standard NACHA-format file with SEC code matching the original entry); return entries appear as Return Addenda Records (Type 99)
Extract the Return Reason Code (field 6 in the addenda record, 3 characters): R01 (Insufficient Funds), R02 (Account Closed), R03 (No Account / Unable to Locate), R04 (Invalid Account Number), R10 (Customer Advises Not Authorized)
Classify returns as retryable vs. non-retryable: R01 and R09 (Uncollected Funds) may be retried; R02, R03, R04, and R10 are non-retryable and require account verification before any retry
For R01/R09, wait at least one business day before retrying; NACHA rules allow a maximum of 2 retries on an NSF return for the same entry
For R10 (unauthorized), do not retry; flag the transaction for compliance review and notify the originator — R10 triggers mandatory action under NACHA rules
Log the original trace number (field 13 in the return entry) to correlate each return to the original forward entry in your system
Known gotchas
NACHA limits debit retries after R01/R09 returns to 2 additional attempts; exceeding this limit violates NACHA rules and can result in ODFI fines
R10 (Customer Advises Not Authorized) is a compliance-critical return — originators must investigate and may be required to reimburse the customer; treat it differently from NSF returns
Return time frames differ by code: most returns have a 2-banking-day window, but R06, R07, R10, and R29 have extended 60-day windows — your system must handle late returns
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