TIN ComplianceA resource from TIN Comply

Guides

Start here

What TIN compliance actually means TIN matching: how it works W-9 solicitation rules Which name goes on the W-9 Vendor renamed, merged or new EIN Backup withholding at 24%Foreign vendors The year-round TIN compliance checklist

Notices and penalties

IRS CP2100 notice and the B-Notice IRS Notice 972CG How the IRS actually judges a 972CG response Why First Time Abate will not fix a 1099 penalty After the denial: 854-C, reconsideration, appeal Your 972CG penalty in IRS Appeals Intentional disregard Your 1099 caused a payee's CP2000

Inside the IRS

The 24% bill for 1099s with no TIN What the IRS does with your CP2100 What the IRS sees about you on PMFOL The TIN Matching program, as the IRS runs it Calling the IRS about a 1099 notice What happens to a paper 1099 inside the IRS Your Form 1096 can silently fail 1099s or W-2s filed under your EIN The IRPTR screen Your letter at the IRS

For payees

Received a B-Notice?TIN doesn't match (payment apps)Subject to backup withholding?How to fill out a W-9 Find a company's EIN All guides →

Tools

Notices

CP2100 B-Notice decision tree B-Notice deadline calculator Solicitation deadline calculator W-9 date checker for Letter 6112

Names, TINs and forms

TIN format checker IRS name control calculator Payer name-line checker Do I need to send a 1099?W-8 validity and late-cure calculator IRS posting-delay estimator IRIS CSV upload checker

Penalties

972CG penalty estimator 972CG penalty cascade calculator Penalty reference code decoder Reasonable-cause self-check Small filer test ($5 million)Missing-TIN exposure calculator CAWR penalty estimator Form 8300 penalty calculator

Deposits and withholding

Backup withholding calculator Form 945 deposit penalty calculator Form 1042 deposit penalty calculator Dishonored deposit penalty (IRC 6657)Form 945 vs 1099-R and W-2G checker

Downloads

Letter and statement templates Compliance calendar (.ics)All calculators →

Forms

Information returns

Form 1099-NEC Form 1099-MISC Form 1099-K Form 1099-INT Form 1099-DIV Form 1099-R Form W-2G Form 1042-S All 35 forms, on one table

Certification forms

Form W-9 Form W-9S Form W-8BEN Form W-8BEN-E Form W-8ECI Form W-8EXP Form W-8IMY

Filing

What's coming for 2027 2025 and 2026 figures FIRE to IRIS How to correct a 1099 Form 945 Form 1099-DA State filing requirements All federal forms →

States

State tax on the payment?

AL AK AZ AR CA CO CT DE DC FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY

Direct filingCF/SF is enoughNo state filingNo income tax

All state requirements →

Industries

By sector

Healthcare Property management Marketplaces and gig platforms Universities and government Financial institutions Legal Gaming and casinos Logistics and freight Crypto and fintech Nonprofits and foundations Insurance All industries →

Reference

Look it up

2025 and 2026 figures Compliance calendar IRS notice decoder Glossary IRS sources Inside the IRS

Filing and matching

FIRE to IRIS (Nov 2026)IRIS portal walkthrough How to correct a 1099 IRS name control rules Bulk TIN matching walkthrough

Letters and lookups

IRS Letter 147C What is a TIN?10DLC: EIN and legal name Form 945 Federal forms All reference pages →

Reference

Reference: figures, calendars, decoders and lookups

Everything on this site that is a table, a date, a definition or a lookup rather than a guide. Figures and deadlines are updated each season from the IRS instructions; the notice decoder and the Inside the IRS pages are built from the Internal Revenue Manual with the section and date cited.

Updated October 3, 2026Also see the guides, calculators and state requirements

In this guide

Look it up
Filing and matching
Letters and lookups

Look it up

Reference

2025 and 2026 figures

Penalty amounts, thresholds, rates and due dates for the current two filing seasons, each sourced to the IRS.

Reference

Compliance calendar

Every 1099, Form 945 and W-9 deadline for 2026 and 2027, with the IRS's own CP2100 run dates.

Reference

IRS notice decoder

Every notice and letter a payer receives about TINs, 1099s and backup withholding: who gets it, what it means, what to do.

Reference

Glossary

The terms the IRS uses around TINs, information returns and withholding, defined from the publications.

Reference

IRS sources

The publications, instructions, regulations and manual sections this site is built from.

Reference

Inside the IRS

How the Service handles 1099 penalties, Form 945 and backup withholding, read from the Internal Revenue Manual.

Filing and matching

Reference

FIRE to IRIS (Nov 2026)

What 1099 filers must do before FIRE closes.

Reference

IRIS portal walkthrough

Filing through the IRIS Taxpayer Portal, screen by screen.

Reference

How to correct a 1099

Type 1 and Type 2 corrections, wrong TINs and deadlines.

Reference

IRS name control rules

Why a correct name can still mismatch, and how the IRS derives the four characters it compares.

Reference

Bulk TIN matching walkthrough

The IRS TIN Matching program for payers, file format to results.

Letters and lookups

Reference

IRS Letter 147C

How to get an EIN verification letter, and the digital substitute now available in Business Tax Account.

Reference

What is a TIN?

SSN, ITIN, EIN, ATIN and PTIN explained, with the format rules for each.

Reference

10DLC: EIN and legal name

Why carrier registration fails on a name mismatch and how to fix it.

Reference

Form 945

Reporting and depositing backup withholding: the return, its deposit schedule and its penalties.

Reference

Federal forms

One page per information return, with thresholds, due dates and whether backup withholding applies.