First Horizon NACHA file requirements

First Horizon accepts NACHA-format ACH files through TreasuryConnect. The bank calls the feature "File Import with Custom Import Maps". Here is what its published documentation requires.

Independent documentation. Not affiliated with or endorsed by First Horizon.

Before you upload, run the file through the free ACH file validator. It checks the structural rules and First Horizon's documented quirks in your browser; the file never leaves your computer.

How First Horizon ACH file upload works

The import feature defaults its Clearing Method to NACHA.
Import failures can be handled per record ("Fail Record") or per file ("Fail File"), chosen on the import map.
A test-import workflow is built into the portal.
Dates in custom-mapped files use forward slashes.

Source: Transcribed from the bank's published service guide; field layouts follow the Nacha standard: First Horizon ACH Custom File Map Import User Guide (October 2025), firsthorizon.com (checked July 2026). Reference. Banks change their requirements; your bank agreement and portal are the authoritative reference.

What to confirm with your First Horizon treasury contact

Four values are assigned per customer and only the bank can tell you them: your Company ID (often not just your EIN), the exact immediate origin value they expect in the file header, whether your agreement is set up for balanced or unbalanced files, and your cutoff times and settlement option. Get them in writing before the first upload.

Building the file

Most accounting software, including QuickBooks and Sage 50, cannot export a NACHA file directly. If your system exports one and First Horizon still rejects it, the validator will usually name the exact line and field. If the reason will not yield, the format setup service works it out with you. This software formats and checks files only. It moves no money; funds move solely through your own bank under your agreement with them.