TIN matching and 1099-K: the 2026 IRS matching program explained

The 1099-K rules changed three times in three years. Operators are confused; processors are inconsistent; the IRS is matching everything. This is the operator's clear walkthrough of where the 2026 1099-K + TIN matching program actually stands, what triggers a B notice, and how to remediate before backup withholding hits your payouts.

What the 1099-K is, in 90 seconds

Form 1099-K is the information return processors and third-party settlement organizations (Stripe, Square, PayPal, Venmo, etc.) file with the IRS to report total payments processed for each merchant. It's how the IRS knows what your gross processing volume was, independent of what you reported on your business return.

Two key boxes on the 1099-K:

• Box 1a: gross amount of payment card / third-party transactions for the year.
• Box 1b: card-not-present transactions (subset of 1a).

The form goes to the IRS, to the merchant (you), and increasingly to states with 1099-K filing requirements (currently MA, VT, MD, IL, VA, NJ, AR, MT, MO, CT, RI, DC).

The 2026 thresholds

The 1099-K threshold history matters because operators carry around the wrong number:

• Pre-2022: $20,000 + 200 transactions (high bar — most small operators didn't get 1099-K).
• 2022 ARPA proposal: $600 (delayed twice).
• 2024 transition: $5,000 single-threshold.
• 2025 transition: $2,500.
• 2026 (current): $2,500 single-threshold.
• 2027+ planned: $600 single-threshold.

For operators running 5–20 brands, every brand processing $2,500+/year now gets a 1099-K. There are no transaction-count thresholds anymore. A brand doing 30 transactions at $100 average ticket triggers a 1099-K.

The IRS matching program: what changed in 2024-2026

Pre-2024 the IRS received 1099-Ks but didn't systematically match them against business returns. That ended with the AUR (Automated Underreporter) program expansion. Now:

• Every 1099-K filed by a processor is matched against the gross receipts box on the matched EIN/SSN's return.
• If 1099-K total > reported gross receipts by > $1,500, a CP2000 notice is generated.
• CP2000 lands 12–18 months after filing. The notice proposes additional tax + interest + accuracy penalty.
• Operators have 30 days to respond with corrected return or explanation (refunds, voided transactions, intercompany transfers, etc.).

For multi-brand operators this matters because each brand's 1099-K reports gross processing — including refunds, chargebacks, voided sales — while your business return reports net revenue. Reconciling the difference is straightforward but requires you to keep the documentation. See marketplace 1099-K reporting for the multi-channel case.

TIN matching: the silent disqualifier

When you onboarded with each processor, you provided a TIN (EIN for entities, SSN for sole proprietors) and a legal name. The processor files the 1099-K under that exact TIN/name pair. The IRS validates the pair against the IRS Master File. If they don't match exactly, the 1099-K is flagged.

Common mismatch causes:

• EIN registered to "Jane Smith Holdings LLC" but processor onboarded as "Jane Smith LLC" (missing word).
• EIN registered to "Acme Brands Inc" but processor entered "Acme Brands Inc." (extra period — IRS Master File is whitespace/punctuation sensitive).
• EIN was reissued / updated but processor never updated their record.
• DBA name used instead of legal entity name.
• Sole prop using SSN with business name attached (IRS expects individual name on SSN-keyed 1099-K).

The B notice cascade

When a TIN mismatch is detected the IRS sends the processor a B notice (CP2100 or CP2100A). The processor is required to forward it to you. You then have 30 days to certify a corrected W-9 to the processor.

If you fix it: nothing further happens.

If you don't fix it: backup withholding kicks in at 24%. The processor must withhold 24% of every payout and remit to the IRS. They will continue withholding until either (a) you certify a corrected W-9, or (b) the IRS issues notice that the TIN is now correct.

If a second B notice arrives within 3 calendar years on the same TIN/name pair without remediation: account lockout. Most processors will pause your account until the issue is resolved with the IRS, not just with them.

Remediation steps

Step 1: pull every 1099-K you've received

Across every processor, every brand. Verify the TIN and legal name match your IRS Master File entry exactly. The IRS Master File is what shows on your most recent IRS letter (CP575 for new EINs, or any letter the IRS has sent the entity).

Step 2: file a corrected W-9 with each processor where the data is wrong

W-9 is the form processors use to capture TIN + name. Submit through their compliance portal — most have a self-service flow. Stripe: Settings > Tax. Square: Settings > Tax forms. Authorize.net: via your ISO. Pay.com: compliance portal.

Step 3: if you've received a B notice, respond within 30 days

The B notice is time-sensitive. Past 30 days the processor must initiate backup withholding regardless of whether you've started the correction.

Step 4: enroll in IRS TIN Matching

The IRS offers an online TIN Matching service free for registered users (irs.gov/tax-professionals/taxpayer-identification-number-tin-matching). You can pre-validate every TIN/name pair across your portfolio in 5 minutes. Strongly recommended before opening any new processor accounts — catches mismatches before they become B notices.

Step 5: clean up state-level filings

Some state thresholds are lower than federal. Massachusetts and Vermont have $600 thresholds, Maryland $600 (with caveats). If your processor doesn't file with the state, you may need to. Check your state's requirements; the penalty for missed state 1099-K filings averages $50–$250 per missed form.

The multi-brand operator complication

Operators running 10–20 brands often have one of three structural mismatches that trigger B notices:

1. Single EIN across multiple processor accounts

Same EIN on Stripe Account 1, Stripe Account 2, Square, and Authorize.net for 4 different DBAs. Each processor files a separate 1099-K under the same EIN. The IRS sees one EIN with 4 separate gross receipts totals — they sum them and match against one return. Usually fine, but reconciliation is harder.

2. Different EIN per brand, common parent

Each brand its own LLC with its own EIN. Each LLC files its own return. 1099-Ks land under the right EINs. Cleanest setup. Common in multi-brand portfolios that did the legal work upfront.

3. Mixed: some brands under EIN A, some under EIN B, some under SSN

The mess. Common in operators who grew organically without entity planning. B notices proliferate; reconciliation is painful; CP2000 notices are likely. Worth the legal cleanup project.

The cleanest setup for portfolio operators: a parent holding entity owns each brand sub-entity, each sub-entity has its own EIN and processor account. Reconciliation is per-brand; consolidation happens at the parent K-1 / 1120 level. This pairs naturally with the parent-merchant-account architecture — same legal logic, different layer of the stack.

What multiflow does about this

For operators consolidating brands behind a parent merchant account architecture, the 1099-K reporting consolidates too — one 1099-K from one acquirer instead of 15 from 15 processors. The TIN/name matching happens once during onboarding, not per brand. Reconciliation against the business return is one number, not 15. See multi-brand reconciliation for the full picture or parent merchant account for the architecture.

One-page operator checklist

• Verify TIN + legal name match IRS Master File for every entity.
• Update W-9 with every processor where data drifted.
• Enroll in IRS TIN Matching service to catch issues pre-emptively.
• Track refunds + chargebacks + voids by brand to reconcile against gross 1099-K totals.
• Respond to any B notice within 30 days — never let backup withholding start.
• Check state 1099-K filing requirements for every state your customers ship to.

The 1099-K + TIN matching program is one of the few compliance areas where the fix is genuinely fast — once you know what the IRS sees and how the matching works. Operators who clean it up once typically don't see another B notice for years.