IRS Publication 5164-A – IRS Forms, Instructions, Pubs 2026 – If you’re a software developer, transmitter, issuer, or applicable large employer (ALE) preparing to file Affordable Care Act (ACA) information returns electronically, IRS Publication 5164-A is a foundational resource. Officially titled “Test Package for Electronic Filers of Affordable Care Act (ACA) Information Returns (AIR) (Tax Year 2015 – Phase I)”, this October 2015 document (Catalog Number 68465N) outlines the testing requirements for the ACA Assurance Testing System (AATS).
Download the official PDF here: https://www.irs.gov/pub/irs-pdf/p5164a.pdf
Although superseded by newer editions (current version is Publication 5164, Rev. December 2025, for Processing Year 2026/Tax Year 2025), Publication 5164-A remains available on IRS.gov and provides essential historical context on the AATS process that continues to govern electronic ACA filing today.
What Is IRS Publication 5164-A?
Publication 5164-A serves as the official test package and user guide for entities required to file Forms 1094-B, 1095-B, 1094-C, and 1095-C electronically through the IRS’s Affordable Care Act Information Returns (AIR) system.
It details how to:
- Apply for and use a Transmitter Control Code (TCC)
- Prepare and submit test transmissions
- Pass the ACA Assurance Testing System (AATS)
- Achieve production-ready status for electronic filing
The publication was released for the initial rollout of mandatory electronic ACA reporting under the Patient Protection and Affordable Care Act (PPACA) and Health Care and Education Reconciliation Act of 2010 (HCERA).
Who Must Use Publication 5164-A (and the AATS Process It Describes)?
Target audience includes:
- Software Developers — Creating origination or transmission software for ACA forms (must pass AATS scenarios annually)
- Transmitters — Third-party filers or issuers sending returns on behalf of others (one-time communication test required in their first year)
- Issuers — Health insurance companies, self-insured employers, government agencies, and other entities filing under IRC Sections 6055 and 6056
- Applicable Large Employers (ALEs) — Businesses with 50+ full-time employees filing Forms 1094-C/1095-C
Key requirement: Filers submitting 250+ returns of the same type must file electronically. Testing via AATS verifies that your software and transmissions meet IRS XML schema, business rules, and communication standards.
Forms Covered in Publication 5164-A
The test package specifically addresses these core ACA information returns (Tax Year 2015):
- Form 1094-B — Transmittal of Health Coverage Information Returns
- Form 1095-B — Health Coverage
- Form 1094-C — Transmittal of Employer-Provided Health Insurance Offer and Coverage Information Returns (standalone only for authoritative transmittal corrections)
- Form 1095-C — Employer-Provided Health Insurance Offer and Coverage
Note: Non-ACA information returns use the FIRE system (see Publication 1220 instead).
AATS Testing Process: Step-by-Step Overview from Publication 5164-A
- Obtain a Transmitter Control Code (TCC)
Submit the ACA Application for TCC via IRS e-Services. Designate roles (Software Developer, Transmitter, Issuer) and contacts. - Prepare Test Submissions
- Use only XML format (no ASCII or PDF).
- Set Test File Indicator to “T”.
- Follow exact test scenarios provided (original and correction submissions).
- Use provided mock data — never live taxpayer information.
- Transmission Methods
- ISS-UI (web browser interface)
- ISS-A2A (Application-to-Application with SOAP/MTOM)
- Validation and Acknowledgment
- Receive a Receipt ID upon acceptance.
- Retrieve acknowledgment files (statuses: Processing, Accepted, Accepted with Errors, Rejected, etc.).
- Early AATS (November 2015) used character-by-character comparison; enhanced environment (January 2016) added full business rule validation.
- Who Must Test and How Often?
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- Software Developers: Pass all applicable scenarios annually for supported forms.
- Transmitters & Issuers: One-time successful communication test (first year only) using approved software.
Correction scenarios must be submitted separately from originals. No extensions, waivers, or stress testing were available in the initial 2015 AATS.
Important Notes from the 2015 Test Package
- Live data is prohibited in testing.
- Software ID must be verifiable.
- A more robust AATS environment launched in January 2016 with improved error messaging.
- Refer to companion publications: Publication 5165 (filing guide), Automated Enrollment External Guide, and AIR Submission Composition and Reference Guide.
Current Version: Publication 5164 (Processing Year 2026)
For 2025 tax year filings (due March 31, 2026, for electronic filers), use the latest Publication 5164 (Rev. 12-2025):
https://www.irs.gov/pub/irs-pdf/p5164.pdf
It retains the same core structure but reflects updated scenarios, mock TIN ranges, and current business rules. AATS testing for TY 2025/PY 2026 is open (check IRS.gov for exact start dates and known issues).
Related current resources:
- Publication 5165: Guide for Electronically Filing ACA Information Returns
- Publication 5258: AIR Submission Composition and Reference Guide
- Publication 5308: Automated Enrollment for ACA Providers
- AATS Information page: irs.gov/e-file-providers/air/affordable-care-act-assurance-testing-system-aats-information-returns
Frequently Asked Questions (FAQs)
- Is Publication 5164-A still relevant in 2026?
It provides excellent background on the origins of AATS testing, but always use the current Publication 5164 for active filings. - Where can I find test scenarios?
Current scenarios are posted on the IRS AATS Information page (updated per tax year). - Do I need to re-test every year?
Software developers generally do (for new forms or years). Transmitters need only a one-time communication test. - What if my test submission is rejected?
Correct errors and resubmit as a new original transmission in AATS. Contact the AIR Help Desk (1-866-937-4130) with your Receipt ID for status changes to Production.
Why Proper AATS Testing Matters?
Successful completion of the process described in Publication 5164-A (and its successors) ensures your software or transmissions are production-ready, prevents costly rejections, and helps you meet ACA reporting deadlines without issues.
For the most up-to-date guidance, always visit the official IRS Affordable Care Act Information Returns (AIR) page and download the latest Publication 5164.
Stay compliant — Test early, use approved software, and reference IRS.gov for schemas, business rules, and AATS updates. Questions about your specific situation should be directed to the IRS AIR Help Desk or a qualified tax professional.
All information sourced directly from official IRS publications and webpages as of February 2026. Always verify the latest revisions on IRS.gov.