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Spotlight PEPPOL BIS Billing 3.0 The EU e-invoicing mandate is here — France Sept 2026, Belgium Jan 2026, Germany 2025.

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Standards

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Tools

X12 826 — Tax Notice

The 826 transmits a tax notice — assessment, refund, adjustment, levy — from a tax administration to a taxpayer or its representative.

Purpose

The 826 documents a formal tax notice: assessment of additional tax owed, refund granted, prior period adjustment, levy notification, lien filing. It carries enforcement weight and a mandatory response deadline.

It is the main output of tax administrations to taxpayers. Acknowledged by 997. Followed by a 813 (Tax Return) if the taxpayer needs to refile.

Envelope structure

The 826 travels within the three X12 envelope levels (ISA/IEA, GS/GE with functional group TN, and ST/SE). Didactic example in release 004010:

x12 example-826.x12 
ISA*00*          *00*          *ZZ*USIRS         *ZZ*TAXPAYER      *260515*1100*U*00401*000000826*0*P*>~
GS*TN*USIRS*TAXPAYER*20260515*1100*1*X*004010~
ST*826*0001~
BGN*00*CP-2026-9911*20260515~
N1*TR*US INTERNAL REVENUE SERVICE*24*EIN-IRS~
NM1*IL*1*WILLIAMS*SARAH*L***34*SSN-PARTIAL~
REF*ZZ*NOTICE-TYPE-CP2000~
REF*ZZ*TAX-YEAR-2024~
AMT*ZZ*4750.00~
DTM*036*20260601~
SE*9*0001~
GE*1*1~
IEA*1*000000826~

Common segments

  • Header — ST, BGN.
  • Tax authority / taxpayer — N1*TR, NM1*IL.
  • Notice type / year — REF*ZZ (CP2000, CP504, etc.).
  • Amount — AMT*ZZ.
  • Response deadline — DTM*036.
  • Summary — SE.

Common pitfalls

  • Notice type catalog: IRS publishes a notice type catalog (CP2000, CP504, LT11); a 826 without typed code is uninterpretable on the receiver side.
  • Statute of limitations: an 826 assessment tied to a prior period may exceed the SoL (3 years usually, 6 if under-reported > 25%); verify before accepting.
  • Levy vs lien: a levy seizes assets; a lien stubs property claims — confusing both has disastrous consequences.

Documentation

The code 826 and the name Tax Notice are public and listed on x12.org/products/transaction-sets. The complete structure of loops, qualifiers and code lists is distributed by DISA via the proprietary Implementation Guides (TR3). ediverse.io covers only public concepts, the envelope and didactic examples.