Guide
How to Prepare for 1099 Filing Season
By Keelstar Team · Updated July 11, 2026
The short answer
Start 1099 filing season preparation in September, not January. Reconcile reportable payments against validated W-9s, run IRS TIN matching on your full payee file, resolve mismatches and missing forms before the filing deadline, and confirm name/TIN combinations match W-9 certifications exactly. Export a gap report weekly: vendors paid over threshold without a validated W-9, failed TIN matches, and unsigned forms. Coordinate with tax leadership on B-notice candidates and backup withholding status. A structured pre-season workflow turns January filing from a crisis into a confirmation exercise.
September–October: W-9 completeness audit
Pull a report of all vendors who received reportable payments year-to-date. Flag anyone without a validated W-9, with a stale form, or with failed TIN validation. Launch a bulk W-9 collection campaign for gaps. Set a November 15 target for 95% completeness on tier-one payees.
November: TIN matching run
Submit your payee file to IRS TIN matching — online for smaller lists, bulk matching for larger filers. Review every failure immediately. Send corrected W-9 requests and B-notices as required. Do not proceed to filing with known bad combinations.
- Match legal name from W-9 to TIN
- Resolve failures before December payment cutoff
- Document B-notice sends for non-responders
- Update vendor master with corrections
December: Payment reconciliation
Reconcile ERP payment totals to 1099 reportable amounts. Confirm entity classifications on W-9s still match reality — vendors may have converted entities mid-year. Process final W-9 corrections before year-end if possible. Hold December payments to vendors with unresolved TIN issues when policy allows.
January: Filing execution
Generate 1099-NEC and 1099-MISC forms using W-9 name and TIN data. Furnish Copy B to payees and file Copy A with the IRS by January 31. Use IRS FIRE system or authorized e-file provider. Retain filing confirmations and vendor delivery proof.
Roles and handoffs
AP owns payment data and W-9 completeness. Tax owns filing execution and B-notice procedures. Define who runs TIN matching, who contacts vendors, and who signs off on the final filing file. Ambiguous ownership is why 1099 season fails in many organizations.
Post-filing: CP2100 response readiness
Even with good prep, CP2100 notices arrive for prior-year mismatches. Maintain your W-9 audit trail, outreach logs, and B-notice records so you can respond within IRS timeframes. Schedule a post-season retrospective: how many gaps remained, what caused them, and what process change prevents recurrence.
Frequently asked questions
- When should AP start 1099 season prep?
- Begin in September or October. This gives time for bulk W-9 requests, TIN matching, vendor follow-up, and B-notice procedures before the January 31 filing deadline for 1099-NEC.
- What payments require a 1099-NEC?
- Generally, payments of $600 or more for services to non-corporate payees — sole proprietors, partnerships, LLCs taxed as partnerships or S-corps, and attorneys. Corporations are typically exempt except for attorneys and certain other payments.
- Can we file 1099s without TIN matching?
- You can file, but unmatched combinations generate CP2100 notices and may require corrected filings and B-notices. Run matching before filing — proactive correction is far cheaper than reactive cleanup.
- What is the 1099-NEC filing deadline?
- Copy A must be filed with the IRS and Copy B furnished to payees by January 31 for the prior calendar year. State deadlines may differ. Missing the deadline triggers IRS penalties that scale with lateness.
Related guides
Put this into a monitored workflow
W-9 Collector handles this continuously — with reminders and an audit trail.