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Form W-9

Form W-9 is the IRS form a vendor gives a county to provide its legal name and taxpayer identification number (EIN or SSN), so the county can pay and report payments.

Almost every county asks for a W-9 before it can set you up as a vendor or pay you. The name must match the IRS records for the tax ID you give.

Use an EIN, not your Social Security number

Sole proprietors can legally use their Social Security number, but a free Employer Identification Number (EIN) from the IRS is safer: W-9s are shared with many offices and may be kept for years. FactWise's Vault stores your EIN encrypted and only shows the last 4 digits.

Keep it current

Send a new W-9 if your business name, structure or address changes. A mismatch can delay payments.

Sources

Last reviewed Oct 30, 2026. This is general information, not legal advice. Laws and thresholds change; check the current statute and the bid documents.

What Is Form W-9? | FactWise