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If that scene feels familiar, you are not alone. Most firms do not struggle because they cannot find clients. You struggle when delivery breaks during peaks, when reviews pile up, and when a single missing TCC stalls an entire run of 1094‑C and 1095‑C files. This guide clears up what Form 4423 is in 2026, how AIR works now, and what you actually need to file on time without burning weekends.
Key Takeaways
- Most filers do not submit a PDF Form 4423 today. If you have an EIN, you apply online through the ACA Application for TCC in IRS e‑Services with ID.me. The e‑file requirement applies when you have 10 or more information returns in aggregate.
- Form 4423 still exists for limited cases. The IRS IRM says Form 4423 can be used by foreign entities without an EIN, or to update an application for an organization without an EIN. Everyone else uses the online ACA application.
- Publication 5165, Publication 5164, Publication 5258, and Publication 5308 are your technical playbooks for testing, schemas, and enrollment. The IRS lists current 2024–2025 revisions on its AIR pages.
- Plan your timeline. The 45-day window is a minimum lead time before your electronic return due date, not a soft target – and mandatory Pub 5164 testing must finish before you file. Build buffer for AATS testing and any communications test your role requires.
- Use the right channel. You will transmit ACA returns through AIR UI or A2A, then retrieve acknowledgements using the correct environment and Receipt ID pattern.
What Form 4423 is in 2026
The plain‑English definition
Form 4423 is the IRS “Application for Filing Affordable Care Act Information Returns.” In 2026, most filers do not mail or upload this form. You complete the ACA Application for TCC online inside IRS e‑Services, which uses ID.me sign‑in. That is how software developers, transmitters, and issuers get their ACA TCCs for AIR.
When Form 4423 still appears
If you are a foreign entity with no EIN that must file ACA returns or you are updating an application without an EIN, the IRM states Form 4423 can be used (here, "foreign" tracks U.S.-person status under tax law – a nonresident alien, foreign corporation, partnership, trust, or estate – not simply physical location outside the U.S.). The IRM also instructs IRS staff to move applicants with EINs to the online application and issue an “Incomplete Form 4423” letter if needed. This is a narrow edge case, but it matters if you support global groups.
Do not confuse IRS Form 4423 with FAA paperwork
The FAA has internal documents with similar numbers that are unrelated. When you search, stay on IRS.gov and other .gov domains, then confirm you are on an ACA AIR page.
Quick wins you can apply today
- Check if your ACA workload hits the electronic filing threshold. If your firm or your client has 10 or more information returns, you must e‑file, which includes AIR filings for 1094‑B/1095‑B and 1094‑C/1095‑C.
- Confirm your ACA Application for TCC is complete in e‑Services and that your responsible official can view the TCC online.
- Pull your current-year Pub 5165 section on acknowledgements and error handling, then line it up with your software’s schema version and test plan.
Pro tip: finish your ACA communications test well before peak. You only need to pass it once as a transmitter or issuer using approved software, but leaving it to the week you plan to file is how late nights start.
Do ALEs need Form 4423 to file with the IRS?
Short answer, no, not in the old “download a PDF and upload it” sense. Applicable Large Employers report coverage using 1094‑C and 1095‑C, and if the aggregate return count across information returns is 10 or more, the IRS requires e‑filing. For ACA forms, that means AIR, which you access with an ACA TCC obtained through the online ACA Application for TCC in e‑Services.
The special paper Form 4423 use case still exists for foreign entities without an EIN. If your ALE has an EIN, go straight to e‑Services, complete Secure Access with ID.me, and submit the online ACA application.
How AIR works now
Roles and TCCs
You can request different roles inside the ACA application, and each role receives its own TCC. TCCs for AIR start with B, C, or T. Use the software developer TCC for testing software, and the transmitter or issuer TCC for actual filings.
| Role in ACA application | When you use it | TCC pattern |
| Software developer | Build and test ACA files, pass AATS | Starts with B, C, or T |
| Transmitter | Send files on behalf of yourself or clients | Starts with B, C, or T |
| Issuer | File for your own entity | Starts with B, C, or T |
Source, IRS AIR guidance and e‑file overview.
Two channels to transmit
- UI, browser based. Upload ACA files, then check acknowledgements.
- A2A, system to system. Enroll first using Automated Enrollment, then manage certificates and endpoints.
Acknowledgements follow specific Receipt ID patterns that differ by environment. Match AATS with IDs that start with AATS109, and production with IDs that start with 109. This single check prevents hours of chasing phantom “missing” feedback.
The e‑file threshold you cannot ignore
Beginning with tax year 2023 filings and forward, the IRS requires electronic filing when you have 10 or more information returns in aggregate. That rule affects AIR, FIRE, and IRIS. It is not just a 1099 rule anymore. If your aggregate count hits 10, plan on electronic.
OMB control number and “is this form still valid”
You will see references to OMB No. 1545‑2251 for Form 4423. OMB’s collection for this control number was extended “without change” on August 27, 2024, which confirms the collection is still approved. The practical filing path in 2026 remains the online ACA Application for TCC for entities with EINs. (omb.report)
If you pull an old PDF from a third‑party mirror, confirm the OMB number on the header, then verify current procedures on IRS.gov. Do not assume an older PDF reflects today’s process.
How to apply for an ACA TCC today
Step 1, set up access
- Create or sign in to your IRS e‑Services account with ID.me.
- Complete Secure Access for the responsible official and contacts listed on the application.
Step 2, complete the ACA Application for TCC
- Choose your roles, software developer, transmitter, issuer.
- Enter responsible official and contact details.
- Identify the forms you will file and your software package.
- Sign the terms with your e‑Services PIN. When your application status is complete, the TCC shows online and is also mailed – the IRS will not issue a TCC over the phone or by email, so do not call expecting verbal disclosure.
Step 3, handle required testing
- Software developers must pass the Affordable Care Act Assurance Testing System, AATS.
- Transmitters and issuers complete a one‑time communications test using approved software.
- Keep Pub 5164 and Pub 5165 close. They map scenarios, validations, and acknowledgements for the year. Do not transmit any production files until your TCC has been issued and the required testing is complete.
Timelines that keep you out of trouble
IRS systems say TCC processing may take up to 45 days. Add your own buffer for AATS or communications testing, plus vendor readiness. If 45 days pass with no reply, call the AIR help line – do not refile a duplicate application. If you handle both FIRE and AIR in peak season, coordinate resources so your team does not idle during ACA acknowledgements.
What you enter in the ACA Application
The online application mirrors the familiar fields you expect.
- Business legal name and EIN
- Responsible official and contacts, with SSN or ITIN as required by IRS systems
- Roles requested and forms supported
- Software information and your contact preferences
Helpful internal checklist
- Confirm your EIN and legal name exactly as shown on IRS records.
- Decide who will own the responsible official role before you start.
- Capture the exact email accounts that will monitor acknowledgements.
- Document your UI versus A2A decision and certificate owners.
AIR resources you should bookmark
- Apply for the Affordable Care Act TCC page, with steps, testing, and help desk numbers, last reviewed December 9, 2025.
- ACA services hub, with the login entry point and tutorial.
- AIR overview page, with UI and A2A links, acknowledgements guidance, and environment notes.
- Technical pubs, Pub 5164, Pub 5165, Pub 5258, Pub 5308, current 2024–2025 revisions.
Save the AIR help desk numbers in your runbook. During peak, a five minute call can beat twenty emails.
Common AIR roadblocks and how to clear them
TCC and identity mismatches
The top cause of rejections is simple, your TCC or EIN on the transmission does not match IRS records, or you mapped the filer and transmitter fields incorrectly. Before you transmit, validate the 5‑character TCC, confirm it is linked to the right EIN and responsible official in e‑Services, and check your schema mapping. If you catch it late, submit a corrected transmission using the original Filing Identifier.
Acknowledgement confusion
Teams often check the wrong environment for status. Match AATS IDs that start with AATS109 to AATS, and production IDs that start with 109 to production. Wait at least ten minutes after you receive a Receipt ID before you request the acknowledgement.
Schema and packaging issues
Use the current year’s Pub 5165 and Pub 5258 to align schema versions, validations, and submission composition. If your software vendor ships a late patch, retest a small file in AATS or a low‑risk production batch, then scale.
Roles and TCC usage mix‑ups
Use the software developer TCC only for software testing, not for production filings. Use the transmitter or issuer TCC for live submissions. The IRS explicitly distinguishes these roles and TCCs.
What about OMB control numbers and old PDFs
You might encounter a 2016‑dated Form 4423 PDF in third‑party repositories that shows OMB No. 1545‑2251. The collection remains approved under that control number, extended in 2024. The existence of an old PDF does not change your 2026 process, finish the ACA Application for TCC online if you have an EIN. If you truly have a non‑EIN foreign filer scenario, the IRM explains when Form 4423 may be used. (omb.report)
Who this helps
If you are a partner or controller juggling ACA alongside year‑end close, your bottleneck is rarely sales. It is delivery, review time, and the lack of a clean, accountable pipeline into AIR. When you standardize your ACA intake, fix TCC ownership, and script your acknowledgement checks, you cut review time and keep promises to clients without all‑hands weekends.
If your internal team is at capacity, consider disciplined help, not a pile of resumes. We have seen firms succeed when offshore capacity is paired with SOPs, documented review steps, and strict control over who owns transmissions and who monitors acknowledgements. That is the difference between extra hands and reliable delivery.
Security, compliance, and work integrity
- Work only on IRS.gov and .gov domains for ACA application and AIR entry points, then sign in with ID.me.
- Keep role‑based access to e‑Services, limit who holds responsible official authority, and rotate certificates on a schedule.
- Document your acknowledgement retrieval process in a checklist so coverage does not depend on one person.
Where Accountably fits, briefly
When CPA and EA firms ask us to help with ACA cycles, we embed trained offshore teams into your workflow, inside your software, and under your SOPs. The point is not more people. It is controlled delivery that protects reviews, deadlines, and data. If you already run a smooth AIR process, great, keep going. If you want production stability during peaks, pair capacity with structure so you can file cleanly and get back to advisory.
Final word
You do not need heroics in February. You need a clean TCC path, roles assigned to the right people, one‑time communications testing done before the rush, and a checklist for acknowledgements. That is how you keep 1094‑C and 1095‑C on schedule and protect client trust. If you want help building the discipline and capacity to do this every year, we can plug in, work inside your systems, and keep your delivery predictable.
Common Mistakes We See Every Season
Most 4423 problems we see are not exotic. They are the same handful of misreadings of the instructions, repeated by filers who treat the form as a one-time paperwork task instead of a controlled SOP. Catching these on a checklist before you mail or fax saves a 45-day re-submission cycle.
Reusable Checklists
These checklists are copy-paste ready for a firm SOP or a foreign-filer onboarding packet. The Block 1 to Block 9 sequence follows the form layout per IRS Form 4423 instructions (Rev. 3-2016).
Pre-submission packet for foreign filers
- Confirm the applicant has no U.S. EIN; if an EIN exists, switch to the online ACA Application in IRS e-Services and stop here.
- Identify at least two Responsible Officials, each 18 or older, with authority to sign on behalf of the organization.
- Collect Responsible Official details: full legal name, title, U.S. citizenship status (Yes, No, or Legal resident alien), date of birth in MMDDYYYY, 10-digit telephone with country code, and email.
- Collect two to ten Contacts with the same data fields as the Responsible Officials.
- Decide which ACA returns the organization will file: 1094-B, 1095-B, 1094-C, 1095-C, or any combination.
- Decide the filer Role (Transmitter, Software Developer, Issuer, or any combination) and Transmission method (ISS-A2A, ISS-UI, or both).
- If Software Developer is checked, gather Package Type (Online, COTS, or In-house), Tax Year, Package Name, Website (if Online), Forms and Transmission Method, Software Contact, email, and telephone.
- Confirm the business address; if the mailing address differs from the physical address, capture both for Block 3.
Block-by-block completion review
- Block 1: mark New application or Revised application; do not leave both blank.
- Block 2: mark Yes for Foreign Filer status.
- Block 3: organization name, DBA only if used for IRS filing, both addresses if they differ, business type from the 12 listed options.
- Block 4: at least two Responsible Officials, each with citizenship status and date of birth in MMDDYYYY.
- Block 5: at least two and no more than ten Contacts; ignore the "at least one" surface cue and follow the instruction text.
- Block 6: select the ACA information return forms the applicant will file.
- Block 7: select Role (Transmitter, Software Developer, Issuer); complete software-package fields only if Software Developer is selected.
- Block 8: select Transmission method (ISS-A2A, ISS-UI, or both).
- Block 9: every Responsible Official signs by hand, prints name and title, and dates the form.
Post-submission tracking
- Submit at least 45 days before the electronic return due date by mail to 230 Murall Drive, Mail Stop 4360, Kearneysville, WV 25430, or by fax to (877) 477-0572 (domestic) or (304) 579-4105 (international).
- Log the submission date, channel, and tracking or fax confirmation number in the engagement file.
- Begin Publication 5164 testing for the chosen transmission method while the TCC application is pending; do not wait for the TCC to arrive before starting test scenarios.
- If no IRS response after 45 days, call the ACA AIR help line at (866) 937-4130 (U.S.) or (470) 769-5100 (international), Monday through Friday. Do not file a duplicate paper 4423.
- On TCC receipt, record the code, role, and forms in a secure register; use the correct TCC for the role and forms when filing.
- Do not transmit any 1094-B, 1095-B, 1094-C, or 1095-C electronic files until the TCC is in hand and Pub 5164 testing has cleared.
- Retain books and records relating to Form 4423 as long as their contents may be material to any IRS administration.
Keep 4423 Season From Stalling
ACA AIR season is a quiet trap for foreign organizations without a U.S. EIN. The 1094-B, 1095-B, 1094-C, and 1095-C electronic deadlines are non-negotiable, but the only path to file them runs through a paper application that the IRS asks you to submit at least 45 days ahead of the electronic return due date (per IRS Form 4423 instructions, Rev. 3-2016). Miss that lead time and the whole season slips, regardless of how clean the underlying coverage data is.
The fix is not more urgency in February. It is upstream discipline on the application and Publication 5164 testing so the TCC is already in hand when the data files are ready.
- Build the 45-day clock backwards from the earliest 1095-B or 1095-C deadline on the engagement calendar and treat that as the hard submission date for Form 4423, not a target.
- Stand up a single source of truth for the two-plus Responsible Officials and the two-to-ten Contacts, with date of birth in MMDDYYYY format and country codes already appended to every international telephone number.
- Run Publication 5164 test scenarios for ISS-A2A or ISS-UI in parallel with the paper application; the TCC is useless if the transmission has not cleared testing.
- Lock in the wet-ink signature step: every Responsible Official signs Block 9 by hand on the same submitted form, every time, before the package leaves the office.
- Track the 45-day IRS response window in the workflow tool and queue a (866) 937-4130 follow-up call on day 46; never re-submit a duplicate 4423 on assumption.
If the paper application bottleneck, Pub 5164 testing, and AIR transmission are pulling senior reviewers off higher-value work each January, that is the part we can carry. Our trained, U.S.-led offshore team plugs into your tax and compliance workflow with documented SOPs and turnaround SLAs, so the 4423 clock is managed before it becomes a deadline conversation.
FAQs
Do I still need a TCC if my software vendor submits for me
Yes. If your vendor is the transmitter of record, they will use their own TCC. If you plan to transmit yourself, you need your ACA TCC. Confirm who is listed as the transmitter on your filings before busy season.
How long does it take to get an ACA TCC
Across IRS systems, TCC processing can take up to 45 days. Start early and build time for AATS or communications testing.
What is the 2026 e‑file threshold for ACA forms
If your aggregate information returns count is 10 or more, you must e‑file. That rule applies to AIR and other IRS e‑file systems.
Do I ever use a paper Form 4423
Only in limited cases. The IRM allows Form 4423 use by foreign entities without an EIN, or to update an application for an organization without an EIN. If you have an EIN, use the online ACA Application for TCC in e‑Services.
Which publications do I need for technical details
Use Pub 5165 for filing guidance and acknowledgements, Pub 5164 for test scenarios, Pub 5258 for submission composition, and Pub 5308 for automated enrollment. Check the IRS AIR page for the latest revision months.