ACH Return Codes Explained

Understanding ACH return codes is essential for managing failed payments. Use our comprehensive guide to look up any ACH return code, understand what it means, and learn how to resolve the issue.

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ACH Return Codes: What They Can Tell You About a Failed Transaction

ACH transactions can fail for a variety of reasons. Sometimes it's a quick fix, other times you may find yourself on hold with your bank's customer support to figure out what went wrong. In some cases, retrying a transaction before identifying the underlying issue can result in subsequent returns, further delays, or even flags placed on your account.

The good news is that there's a built-in system that can help you figure out what's going wrong on your own. ACH return codes are standardized codes that start with the letter R followed by a number from 01 to 85. When a payment fails, one of these codes will appear in the transaction record and identify the specific reason for the return.

However, only knowing the code or its title is not always enough to resolve a payment issue. Identifying the return code is one thing, but knowing which actions to take next is another. That's why Slash put together this guide to help you navigate the ACH return code system. Below, you'll find everything you need to understand return codes, including key terms, what each code means, how they relate to different SEC codes and transaction types, and the steps you can take to resolve each code from 01 to 85.

Understanding the ACH system

The Automated Clearing House (ACH) is a batch-based payment network that moves money between U.S. bank accounts. It's commonly used for bill payments, direct deposits, payroll, and other bank-to-bank transfers. Instead of processing each transaction individually, ACH groups payments into batches that are processed in bulk multiple times per day. This structure makes ACH efficient and cost-effective, particularly for recurring or high-volume payments. However, because transactions are held by banks in certain batches, it can take between 1-3 business days for funds to fully settle.

Who administers the ACH network?

The ACH network is administered by Nacha (National Automated Clearing House Association), a nonprofit organization that establishes the rules and operating standards for ACH payments. Nacha works with two primary ACH operators: the Federal Reserve and The Clearing House's Electronic Payments Network (EPN), which handle the actual clearing and settlement of transactions. ACH transfers are also subject to risk and fraud controls set by financial institutions and network rules. While Nacha sets a per-transaction limit (currently $1 million for most standard ACH payments), individual banks may impose lower limits based on their own policies.

How ACH return codes are defined

Nacha is also responsible for defining and maintaining ACH return codes. These codes explain why a transaction was returned and provide standardized guidance to banks, payment processors, and payment originators. Although new codes may be introduced and definitions may evolve over time, the overall return code framework remains relatively consistent. Our guide is based primarily on the "Nacha ISO 20022 Guide to Matching U.S. ACH Return Code Items" (August 2023), along with cross-referenced industry sources.

Glossary

One of the first hurdles to understanding the ACH system is navigating the many acronyms it uses. While they can seem like dense financial jargon at first, most of the terms involved in the ACH return code system are relatively straightforward once defined. Below are the key words and acronyms you'll need to know to get the most out of this guide.

General banking & ACH network acronyms

Acronym	Term	Definition
DFI	Depository Financial Institution	A bank or credit union that participates in the ACH network and holds deposit accounts.
ODFI	Originating Depository Financial Institution	The financial institution that initiates an ACH transaction on behalf of the originator.
RDFI	Receiving Depository Financial Institution	The financial institution that receives the ACH entry and posts it to the receiver's account.
OFAC	Office of Foreign Assets Control	A U.S. Treasury department that enforces economic and trade sanctions. ACH transactions must comply with OFAC regulations.
SEC	Standard Entry Class	A three-letter code that identifies the type of ACH transaction and how it was authorized.
IAT	International ACH Transaction	An ACH entry involving a financial institution outside the United States, with additional compliance and screening requirements.

ACH credit acronyms

An ACH credit is a "push" payment, meaning you (the sender) initiate the transfer and authorize your bank to send money to someone else's account. The recipient doesn't request the funds; you're the one directing the payment. Sometimes that's a manual action, like logging into Slash to pay a vendor or move money between accounts. Other times it happens automatically, like using direct deposit for payroll or setting up recurring payments that go out on a set schedule.

Acronym	Term	Definition
CCD	Corporate Credit or Debit	An ACH format commonly used for business-to-business payments, including vendor payments and corporate transfers.
CTX	Corporate Trade Exchange	An ACH credit format used for corporate payments that includes detailed remittance information.
ENR	Automated Enrollment Entry	An ACH credit entry used by federal agencies to enroll recipients in direct deposit for government benefit payments.
XCK	Destroyed Check Entry	An ACH entry used when a physical check is lost or destroyed during processing but sufficient information exists to create an electronic entry.

ACH debit acronyms

An ACH debit is a "pull" payment, meaning the recipient initiates the transfer and pulls funds from the sender's bank account. Unlike an ACH credit, the money moves because the recipient has authorization to collect it, not because the sender actively pushes it out each time. These are commonly used for things like bills, subscription services, loan payments, and other recurring charges.

Acronym	Term	Definition
ARC	Accounts Receivable Entry	An ACH debit created when a consumer check received by mail or drop box is converted into an electronic payment.
BOC	Back Office Conversion	An ACH debit created when a consumer check is converted to an electronic entry in a merchant's back office after purchase.
POP	Point-of-Purchase Entry	An ACH debit created when a consumer check is converted to an electronic payment at the point of sale.
RCK	Re-presented Check Entry	An ACH debit used to electronically re-present a consumer check that was returned for insufficient funds.
TEL	Telephone-Initiated Entry	An ACH debit authorized by a consumer over the phone.
WEB	Internet-Initiated Entry	An ACH debit authorized by a consumer through the internet or a mobile application.

Where to find ACH return codes in your Slash dashboard

If one of your outbound ACH transfers is returned to your Slash account, you can quickly locate the associated return code by following these steps:

Filter for returned transactions

Go to the Transactions page in your dashboard. Click the "Status is" filter and select "Returned" from the dropdown menu. This will display all transactions that have been returned, with the most recent transactions at the top.

Open the transaction details

Click on the specific payment you want to review. A side panel will open on the right side of your dashboard with additional information about the transaction. Expand the section labeled "Advanced transaction details." The ACH return code will be listed there.

Click the return code for more information

If you click on the return code shown in the transaction details, you'll be directed to the corresponding entry in our online ACH return code index, where you can see what the code means and how to resolve it.

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