ACH Standard Entry Class code

ARC SEC code: Accounts Receivable Entry

Check received by mail or at a drop box, converted to a one-time debit.

What ARC is for

A check received by mail or in a drop box is converted into a one-time ACH debit; the paper check is not presented.
Common for billers that receive mailed checks in volume, such as utilities and lenders.

The account the paper check is drawn on.

Authorization

The Originator gives clear notice, before receiving the check, that it may be converted to an electronic payment; sending the check after that notice authorizes the debit. Only checks the Rules define as eligible items may be converted; check the eligibility list before converting.

A summary in general terms: the Nacha Operating Rules set the exact requirements, and Regulation E adds its own for consumer accounts.

Debits, credits and addenda

Debits only. A credit sent as ARC is returned R36.

Addenda on a forward entry: none on the forward entry. Returns (addenda type 99) and Notifications of Change (type 98) follow their own layouts whatever the SEC code.

Returns

Besides the general codes, check-conversion debits have their own: R37 when the check was also presented (60 days, Written Statement of Unauthorized Debit), R38 for a stop payment on the check (60 days) and R39 for an ineligible or already-paid check (2 banking days).

Common mix-ups

ARC, BOC and POP all turn a paper check into a one-time ACH debit. The difference is where the check was received: by mail or in a drop box (ARC), in person but converted later in the back office (BOC), or at the point of purchase, where the check is voided and handed back (POP).

Where ARC sits in a NACHA file

The SEC code is a batch-level field: positions 51–53 of the Company/Batch Header record (type 5), so every entry in the batch shares it, and a file that mixes SEC codes puts them in separate batches. The batch header also carries the Company Name, Company Identification and Company Entry Description that Receivers see on their statements.

To read a ARC batch record by record, open the file in NACHA Navigator, a free sister site that parses NACHA files in your browser without uploading them.

Look up ARC from code or an AI agent

REST · GET · no key

curl -s 'https://payopskit.com/api/v1/codes/ARC?set=ach-sec'

MCP · tools/call · lookup_payment_code

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "lookup_payment_code",
    "arguments": {
      "code": "ARC",
      "set": "ach-sec"
    }
  }
}

Response (JSON)

{
  "code": "ARC",
  "set": "ach-sec",
  "found": true,
  "matches": [
    {
      "set": "ach-sec",
      "code": "ARC",
      "name": "Accounts Receivable Entry",
      "description": "Check received by mail or at a drop box, converted to a one-time debit.",
      "details": {
        "direction": "debit",
        "addendaTypes": null,
        "minAddenda": 0,
        "maxAddenda": 0
      }
    }
  ]
}

The MCP server is at /mcp (Streamable HTTP, no key); the API and MCP docs show how to connect Claude, Cursor or VS Code.

Source: Nacha Operating Rules, Appendix Three (Standard Entry Class codes). The code’s name is the Rules’ own; the rest is this site’s plain-language summary, informational and not a substitute for the Rules or your ODFI agreement.