Year-End 1099 Compliance Checklist
for AP Teams

Why a Checklist Matters

Every January, AP teams across the country scramble to meet 1099 filing deadlines with incomplete vendor data, unverified TINs, and last-minute threshold calculations. The result: late filings, incorrect returns, and penalties that could have been avoided with a few months of structured preparation.

This checklist breaks the 1099 compliance process into manageable monthly tasks. Follow it from October through March, and you'll enter filing season with clean data, verified TINs, and the confidence that your returns are accurate.

October: Audit and Collect

October is your foundation month. The goal is to identify every vendor who may require a 1099 and ensure you have current taxpayer information on file.

Vendor Master File Audit

• Pull a complete vendor list from your accounting system or ERP. Include all vendors paid during the calendar year, regardless of amount.
• Flag vendors missing a W-9. Any vendor without a W-9 on file is a compliance gap. If they end up above the $2,000 threshold, you'll be filing a 1099 with unverified information.
• Identify entity types. Review the W-9s you have to confirm whether each vendor is an individual/sole proprietor, LLC, partnership, or corporation. Remember that payments to C-corps and S-corps are generally exempt (with exceptions for attorneys and medical payments).
• Check for duplicate vendors. Duplicate vendor records can lead to split payments that individually fall below the threshold but together exceed it. Clean your vendor master file now.

W-9 Collection Campaign

• Send W-9 requests to all vendors missing forms. Use a standard email template with a clear deadline (aim for November 15).
• Send reminder requests to vendors with W-9s older than 3 years. Business names, entity types, and TINs can change. A periodic refresh keeps your data current.
• Track responses. Maintain a log of who has responded, who hasn't, and follow-up dates. Consider withholding future payments until a W-9 is received for non-responsive vendors.

November: Verify and Resolve

November is your verification month. With W-9s collected (or in progress), run your TIN matching and begin resolving issues.

TIN Matching

• Run a full bulk TIN match on every vendor in your master file. Upload all name/TIN pairs—not just the ones you expect to be above threshold. Payment amounts can change between now and December 31.
• Review IRS result codes for each record. A "0" code means the TIN matched. Any other code means action is required.
• Categorize mismatches. Common reasons include typos on the W-9, name changes (marriage, DBA changes), and vendors who provided an SSN when they should have provided an EIN (or vice versa). See TIN matching for details on each scenario.

Mismatch Resolution

• Contact vendors with mismatched TINs. Send a solicitation letter requesting a corrected W-9. Include the specific issue if possible (e.g., "The name on your W-9 does not match IRS records for the TIN provided").
• Set a resolution deadline of December 15. This gives you two weeks of buffer before year-end.
• Document your efforts. If the IRS later questions a return, your solicitation records demonstrate reasonable cause—a defense against penalties under IRC Section 6724.

December: Finalize and Prepare

December is your preparation month. Payment totals are nearly final, and all TIN issues should be resolved or documented.

Payment Threshold Calculations

• Run a preliminary 1099 report from your accounting system. Identify all vendors at or above the applicable threshold ($2,000 for most categories, $10 for royalties).
• Check for late-year payments that could push a vendor over the threshold. Accounts payable runs in December can shift vendors from below to above $2,000.
• Determine which form each vendor needs. Use our 1099-NEC vs. 1099-MISC guide for payment type classification.

Final TIN Verification

• Re-run TIN matching on any vendors who submitted updated W-9s in November or December.
• Flag unresolved mismatches. For vendors who did not respond to your solicitation, note whether backup withholding at 24% should be applied to future payments.
• Document any vendor you cannot verify. Your file should show a clear audit trail: W-9 request sent, TIN match attempted, result code received, solicitation sent, response (or non-response) logged.

Filing Preparation

• Choose your filing method. Businesses filing 10 or more information returns of any type must e-file. BoomTax supports bulk e-filing for both NEC and MISC forms.
• Prepare recipient copies. These must be mailed or e-delivered to payees by January 31.
• Test your filing workflow. If you're using a new filing service, do a test run now rather than January 30.

January: File 1099-NEC (Deadline: January 31)

January is execution month. The 1099-NEC has the tightest deadline of all information returns, and there is no automatic extension available.

Early January (Jan 1–15)

• Finalize payment totals. All 2026 payments should be recorded and classified by now.
• Generate your 1099-NEC file. Export the data from your accounting system in IRS-compatible format.
• Run one final TIN match on your NEC filing population. This is your last chance to catch mismatches before filing. Any vendor with a mismatch code should be flagged for review.
• Review for backup withholding. If you withheld at 24% from any vendor, ensure Box 4 reflects the correct amount.

Mid-January (Jan 15–25)

• File 1099-NEC forms with the IRS. Use BoomTax for e-filing. Don't wait until January 31—submit early to allow time for rejection remediation.
• Mail or e-deliver recipient copies. Every payee on a 1099-NEC must receive their copy by January 31.
• Submit state filings. If your state is in the Combined Federal/State Filing (CF/SF) program, your federal filing may automatically satisfy the state requirement. If not, file separately with each applicable state.

Late January (Jan 25–31)

• Check for IRS rejections. If any filings were rejected (bad TIN format, invalid data), correct and resubmit immediately.
• Confirm recipient delivery. Verify that all payee copies were mailed or delivered.
• Document completion. Save filing confirmations, transmittal records, and any rejection/correction logs for your audit trail.

February: File 1099-MISC (Paper Deadline: February 28)

If you're paper-filing 1099-MISC forms (for businesses filing fewer than 10 returns), the deadline is February 28. Most businesses should be e-filing, which pushes the deadline to March 31.

• File 1099-MISC paper returns by February 28 if applicable.
• Begin processing corrections for any 1099-NEC forms that contained errors discovered after filing. The sooner you correct, the lower the penalty—corrections filed within 30 days of the deadline incur only a $60 per form penalty instead of $330+.
• Monitor for CP2100/CP2100A notices. The IRS typically begins sending these in the spring for the prior year's filings. If you receive one, start the B-Notice response process immediately.

March: E-File 1099-MISC and Wrap Up (Deadline: March 31)

March 31 is the e-filing deadline for 1099-MISC forms. It's also your opportunity to close out the compliance cycle for the year.

• E-file 1099-MISC forms by March 31. Again, submit early to allow time for rejection handling.
• File any remaining corrections. Both Type 1 and Type 2 corrections should be submitted as soon as errors are identified.
• Complete state filing obligations. Confirm that all state-specific filings have been submitted. Some states have their own deadlines that differ from federal dates.
• Conduct a post-mortem. Document what worked, what didn't, and what you'd change for next year. Common areas for improvement include:
  • W-9 collection response rates
  • TIN match timing (earlier is better)
  • Vendor classification accuracy
  • Filing workflow efficiency

The Consolidated Checklist

Here's the full checklist in one view. Print this or save it for reference:

How TINCorrect Fits Into the Checklist

TINCorrect appears at three critical points in the timeline: the November bulk match, the December re-verification, and the January final check. Here's how the process works:

For high-volume operations, the TINCorrect API can automate TIN verification as part of your vendor onboarding workflow, so you're matching TINs year-round rather than doing it all in November.

State Filing Requirements

Federal filing is only half the equation. Most states require their own copy of 1099 information returns. There are three ways states collect this data:

1. Combined Federal/State Filing (CF/SF) — Participating states receive 1099 data automatically when you e-file with the IRS. This is the easiest path and covers the majority of states.
2. Direct state filing — Some states require separate submissions to their department of revenue, often with different formats or deadlines.
3. No state requirement — A handful of states (including those with no income tax) do not require 1099 filings.

BoomTax handles state filing requirements automatically, including CF/SF participation and direct state submissions where required.

Frequently Asked Questions

Get Started Today

Don't wait until January to start your 1099 compliance process. Create a free TINCorrect account and run your first bulk TIN match today. When you're ready to file, BoomTax handles e-filing, state filing, and recipient copy delivery in one platform.

Author

Ken Ham

Founder at TINCorrect

Passionate about making tax identity verification simple so businesses can focus on what matters.