IRS Pub. 1220: Record Layout, FIRE Upload, and Deadlines

IRS Publication 1220 is the technical specification for transmitting information returns — the 1099 series, 1098 series, Forms 1097-BTC, 3921, 3922, the 5498 series, Form 8027, Form 8955-SSA, and Form W-2G — electronically through the FIRE system.¹ It defines the fixed-length, 750-character record layout the IRS expects, and if your file deviates from that spec, the transmission is rejected. One thing to know before you invest heavily in Pub 1220 tooling: the IRS plans to retire FIRE after the 2026 filing season and move all electronic information-return filing to the newer IRIS platform beginning with returns filed in 2027.²

Who Has to File Electronically

Starting with tax year 2023, the electronic filing threshold dropped from 250 returns to 10. The count aggregates across nearly all information return types, so six Forms 1099-NEC plus four Forms 1099-INT puts you over the line and requires electronic transmission.¹ The underlying statute, 26 U.S.C. § 6011(e), set the applicable number to 10 for calendar years after 2021.³

Below 10 returns across all covered types combined, paper filing is still allowed. At or above 10, electronic is mandatory, and the IRS treats a paper return filed by someone who was required to e-file as a failure to file for penalty purposes.

Get a Transmitter Control Code First

You cannot upload anything to FIRE without a Transmitter Control Code — a five-character alphanumeric identifier that begins with a number.⁴ The paper Form 4419 was phased out on August 1, 2022; the current path is the online IR Application for TCC.⁵

The application runs through ID.me. You’ll create a five-digit PIN to sign it and supply your business’s legal name, EIN, physical and mailing addresses, business structure, and the specific forms you plan to transmit. Every responsible official on the application signs with their own PIN. The IRS asks that you submit the request by November 1 of the year before returns are due and allow up to 45 days for processing.⁶

The application distinguishes an issuer, which files only for its own company across any number of locations, from a transmitter, a third party that files on behalf of other businesses.⁴ Two boundaries worth flagging. First, a FIRE TCC and an IRIS TCC are not interchangeable. If you intend to use both systems during the transition, apply for both codes separately.⁷ Second, the IR Application for TCC is not the same as an EFIN or PTIN application; those cover different IRS programs.

The Pub 1220 Record Layout

Every file is a sequence of fixed-length records, each exactly 750 characters. Wrong length, wrong order, or a missing record type, and the transmission is rejected wholesale.⁸

The hierarchy runs like this:

Transmitter “T” Record. The first record in the file, identifying the sender by TCC.
Payer/Issuer “A” Record. Follows the T record. Carries the payer’s TIN, name, and address, plus a Form Indicator Code that tells the IRS which return type the following payee records represent.
Payee “B” Records. One per recipient. Contain the payee’s TIN, name, address, and dollar amounts, with field positions that map directly to the numbered boxes on the paper form.
End of Payer “C” Record. An optional summary after the last B record for a payer, totaling record counts and payment amounts.
State Totals “K” Record. Used when participating in the Combined Federal/State Filing Program.
End of Transmission “F” Record. Always the final record, closing the file.

Dollar Fields

Money fields are where first-time filers stumble most often. Every amount is right-justified, padded with leading zeros to fill the field width, and contains no decimal point. A payment of $1,250.00 goes into the file as 000000125000. Left-justify it, or leave the period in, and the IRS either rejects the file or, worse, credits the payee with the wrong number.

The B Record Changes Shape by Form

The B record is the trickiest piece of Pub 1220 because its field positions depend on the Form Indicator Code in the preceding A record. A B record built for Form 1099-NEC uses different amount fields than one built for Form 1099-INT. The B record also carries indicator flags for special situations, including foreign addresses and the Second TIN Notice indicator (which you set when the IRS has previously notified you of a TIN mismatch for that payee). Misaligned B-record fields are among the most common causes of an Accepted with Errors result.

Uploading Through FIRE and Reading the Response

With a validated file, you log into fire.irs.gov using your TCC and password. The system asks whether you’re uploading a Test file or a Production file.⁹ If it’s your first filing or you’ve made significant software changes, run a Test first. The test uses the same mechanics as production but does not enter IRS records, so it catches structural problems before they count against a deadline. Once the test passes, upload the same file as Production.

FIRE assigns a Submission ID and you come back later to Check File Status. You’ll see one of three results:

Accepted. The file passed every technical check and is in the processing pipeline. Nothing else to do unless you later find a data error.
Accepted with Errors. The file was processed but individual records failed validation. An error report lists which ones and why. The submission counts as filed; you fix the flagged records with a correction file.
Rejected. A structural problem — record length, invalid TCC, broken sequence — stopped processing. The IRS treats a rejected file as never filed, so you fix the problem and resubmit the entire file as a replacement.

Corrections vs. Replacements

Confusing these two doubles your work.

A replacement file applies only after FIRE rejected the original outright. Because nothing entered IRS records, you upload the whole corrected file again, designated as a Replacement.

A correction file applies when the original was accepted (with or without errors) but individual payee records held wrong data. You do not resubmit the whole original. You build a new file containing only the B records that need fixing, wrapped in the required T, A, and F records, and each corrected B record carries a Correction Indicator so the IRS overwrites the original data instead of treating your correction as a duplicate.

File corrections as soon as you find the error. Stale bad data generates payee mismatch notices, and the longer the delay, the higher the penalty tier if the IRS scrutinizes the timing.

Deadlines for the 2026 Filing Season

For returns covering tax year 2025:

Form 1099-NEC: January 31, 2026. Because that date is a Saturday, the deadline shifts to Monday, February 2, 2026.
Most other 1099 forms, the 1098 series, Forms 3921 and 3922, and Form W-2G: March 31, 2026, for electronic filers. Paper filers face the earlier March 2, 2026, deadline.¹⁰

The 1099-NEC deadline is the tightest because the IRS matches nonemployee compensation against individual returns filed the same season.

Extensions and Waivers

Form 8809 gives you an automatic 30-day extension for most information return types — the 1099 series other than 1099-NEC, W-2G, 1042-S, and the 5498 series. Filed electronically through FIRE by the original due date, the extension is granted automatically.¹¹

Form 1099-NEC and Form W-2 do not qualify for the automatic extension. To get extra time for those, you file a paper Form 8809, select one of the applicable reasons on line 7, and sign it. A second 30-day extension is available only in hardship situations and must be filed on paper with a written explanation before the first extension expires.

Form 8508 is the separate route for waiving the electronic filing requirement itself. A first-time request is granted automatically. For subsequent requests based on undue financial hardship, you attach two third-party cost estimates comparing electronic and paper filing costs. If your waiver for original returns is approved, it automatically covers corrections.¹²

Penalties

Penalties are assessed per return, so costs scale fast on high-volume files. For returns due in 2026:

Filed up to 30 days late: $60 per return.
Filed 31 days late through August 1: $130 per return.
Filed after August 1 or not filed at all: $340 per return.
Intentional disregard: $690 per return or a percentage of the reportable amount, whichever is greater, with no annual cap.

Annual caps depend on size. Filers with average annual gross receipts above $5 million are capped at $4,191,500 for the highest tier; smaller filers (at or below $5 million) are capped at $1,397,000.¹³ Separate penalties apply for failing to furnish correct payee statements on time, and paper-filing when you were required to e-file counts as a failure to file rather than a procedural slip. For a filer submitting 500 forms a month late, the difference between the 30-day tier and the after-August tier is $140,000.

Planning for the FIRE-to-IRIS Transition

Both FIRE and IRIS are available for the 2026 filing season. After that, IRIS is the only channel.² For Pub 1220 filers, the relevant IRIS channel is Application-to-Application (A2A), which accepts transmissions in XML rather than the fixed-length ASCII layout Pub 1220 defines.¹⁴

Two practical implications. First, moving from a 750-character flat-file to XML is a real development effort, not a configuration change; software vendors and in-house teams should already be building toward IRIS A2A for the 2027 filing season. Second, because the FIRE and IRIS TCCs are separate credentials, existing FIRE users should complete the IRIS Application for TCC well before FIRE goes dark to avoid a scramble when the sunset date arrives.⁷

1
Internal Revenue Service. Topic No. 801, Who Must File Information Returns Electronically
2
Internal Revenue Service. Filing Information Returns Electronically (FIRE)
3
Office of the Law Revision Counsel. 26 USC 6011 – Return Requirements
4
Internal Revenue Service. About Information Returns (IR) Application for Transmitter Control Code (TCC) for Filing Information Returns Electronically (FIRE)
5
Internal Revenue Service. Update – Form 4419 Phased Out Effective August 1, 2022
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Internal Revenue Service. Topic No. 802, Applying To File Information Returns Electronically
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Internal Revenue Service. Information Returns Intake System (IRIS) – IRIS 101
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Internal Revenue Service. Publication 1220 – Specifications for Electronic Filing of Forms 1097, 1098, 1099, 3921, 3922, 5498, and W-2G
9
Internal Revenue Service. Filing Information Returns Electronically (FIRE)
10
Internal Revenue Service. General Instructions for Certain Information Returns (2025)
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Internal Revenue Service. About Form 8809, Application for Extension of Time To File Information Returns
12
Internal Revenue Service. Application for a Waiver From Electronic Filing of Information Returns (Form 8508)
13
Internal Revenue Service. Information Return Penalties
14
Internal Revenue Service. E-file Information Returns With IRIS