Form W-9 for government contractors
A federal contract does not usually begin with a Form W-9. It begins with a SAM.gov registration, which collects the same legal name and the same taxpayer identification number for the same underlying reason. The W-9 shows up later, from primes, from subcontractors, and from state purchasing offices.
SAM.gov, FAR 52.204-3, and where the W-9 fits
- Federal prime contract
- Register the entity in SAM.gov. Registration collects the TIN
- Solicitation without the SAM clause
- FAR provision 52.204-3 collects the TIN in the offer instead
- A prime or a sub paying you
- An ordinary Form W-9 request
- State, county or school district
- A W-9, often on the buyer’s own substitute form
- Reporting
- A federal executive agency reports payments for services in box 1a of Form 1099-NEC even to a corporation
- A return you never see
- Form 8596, filed quarterly by the agency under IRC 6050M for contracts over $25,000
Why the agency may never send you a W-9
The obligation runs the other way in federal contracting. Under 31 U.S.C. 7701(c) each contractor doing business with a government agency has to furnish its TIN to that agency, and FAR subpart 4.9 implements that requirement in the acquisition system alongside the reporting rules in IRC sections 6041, 6041A and 6050M. The agency therefore already knows it needs your number before you have thought about it, and it has two established channels for getting one. The first is your entity registration in SAM.gov, which is a condition of award under FAR 4.1102 and FAR 52.204-7. The second is FAR provision 52.204-3, prescribed for solicitations that do not carry the SAM clause, which asks the offeror for its TIN, its type of organization, and whether it is owned or controlled by a common parent.
Look at what 52.204-3 collects and the resemblance is obvious. A legal name, a classification, a nine-digit number, an option to say the number has been applied for. That is Line 1, Line 3a and Part I of a Form W-9 wearing a different hat, plus a common-parent question the W-9 has never asked. So a contractor working directly for an agency can go years without filling in a W-9 and still have handed over everything a W-9 would have carried.
The provision warns that failing to furnish the information may produce a 31 percent reduction in payments otherwise due. Backup withholding has not run at 31 percent since 2001. The operative rate under IRC 3406 is 24%, and it is the one an agency payment office will actually apply. How the mechanism works
SAM registration and a Form W-9 do different jobs
| SAM.gov registration | Form W-9 | |
|---|---|---|
| What it establishes | Eligibility to receive a federal award, plus banking details and a long set of representations | That a name and a TIN belong together, and that you are a U.S. person |
| Legal hook | FAR 4.1102 and FAR 52.204-7 | IRC 6109, with the reporting and withholding rules under 6041 and 3406 |
| Where it ends up | A government system at sam.gov | The requester’s vendor file. It is never filed with the IRS |
| Asks for bank account details | Yes, for electronic funds transfer | No. Anything calling itself a W-9 and asking for your account number is not one |
| Identifier assigned | A 12-character Unique Entity ID, which replaced the DUNS number in April 2022 | — |
| Expiration | Registration lapses and must be renewed annually | None. Detail |
| Cost | Free | Free |
| Signed under penalty | Annual representations and certifications | Part II, once. What you certify |
Registration and the Unique Entity ID are free and are obtained in one place. Third parties sell "registration assistance" at prices that sometimes run into four figures, and a parallel industry sends urgent renewal emails from lookalike domains. The same pattern reaches W-9 requests, because a form bearing an EIN and a signature is worth stealing. Handling the form safely
The corporate exception has a federal-agency hole in it
Most incorporated vendors go their whole lives without receiving a Form 1099, because payments to a corporation are generally outside information reporting. Federal contracting is one of the places that stops being true. The instructions for Forms 1099-MISC and 1099-NEC list payments by a federal executive agency for services among the reportable payments to corporations, and they say plainly that such agencies must report those payments in box 1a of the 1099-NEC. An engineering firm incorporated in Virginia that has never had a 1099 in the mail will start getting them the year it wins its first federal contract.
The term has a definition worth knowing, because it draws the boundary. Form 8596 sets it out: a federal executive agency is any executive agency as defined in 5 U.S.C. 105 other than the Government Accountability Office, any military department under 5 U.S.C. 102, and the United States Postal Service and the Postal Rate Commission.
Exempt payee code 5 on Line 4 remains available to you as a corporation, and it remains worth entering, but do not expect it to stop the 1099. The code addresses backup withholding. Whether a payment gets reported at all is a separate question decided by the payment type and the identity of the payer. Three exemptions, often confused
What the agency files about you
Two returns, and you file neither.
Form 8596 carries exceptions, and the useful one is size. A contract or contract action for $25,000 or less needs no filing, and neither does one whose terms have every federal payment made on or before the 120th day after the date of the contract action. An increase of more than $25,000 obligated in a single contract action gets treated as a new contract and reported for the quarter it happens in. None of this is your paperwork. It is worth knowing about because it explains why a contracting officer treats a transposed digit in your TIN as a real problem rather than a clerical one.
Subcontracts: the carve-out stops at the agency
A prime contractor is a company. It is not a federal executive agency, and the reporting rules key off the identity of the payer. So the same dollars can produce two different answers as they move down the chain. When the agency pays the prime for services, the payment is reportable even if the prime is incorporated. When the prime pays an incorporated subcontractor out of that money, the ordinary corporate payee exception applies and no 1099-NEC is due. The exception does not flow down, and neither does its absence.
Primes collect W-9s from every subcontractor anyway. They have to, because the exception only becomes available once you know the sub is a corporation, and only the W-9 establishes that. Add audit exposure, flow-down clauses and a contracting officer who may ask, and holding the form costs less than explaining why you do not have it.
- Collect the W-9 at subcontract award, before the first invoice clears. Wording and timing
- Run TIN matching on the whole vendor file before filing season rather than after a CP2100 arrives.
- A sub who will not send one gets 24% withheld and a documented paper trail. The procedure
- Keep the forms. Federal work tends to attract records requests years after the money moved. Retention
- Do not assume a sub’s SAM registration substitutes for your W-9. Your file has to stand on its own.
State, county and local purchasing
State and local buying is more familiar territory and slightly more annoying. A state agency, a county, a school district or a transit authority is not a federal executive agency, so its payments to a corporation fall under the corporate payee exception in the ordinary way. What these buyers do have is vendor portals, and forms of their own. Many states issue a document titled Substitute Form W-9 that reproduces the federal lines and adds a state vendor number, a remittance address, or a certification about outstanding state tax liabilities. That is permitted, within limits: a substitute has to carry the certifications and the substance of the federal form. What a substitute must contain
Two things catch vendors here. Several states operate their own withholding regimes on payments to out-of-state contractors, which have nothing to do with IRC 3406 and are not switched off by anything you write on a W-9; the state revenue department or your own advisor is the place to settle that. And a government entity is often the payee rather than the payer, the case exempt payee codes 2 and 3 cover. A city asked for a W-9 by one of its own vendors enters code 3. All thirteen codes
Frequently asked questions
Do I need a W-9 if my company is registered in SAM.gov?
For the contracting agency, usually not. Your registration already carries the legal name and the taxpayer identification number, and where a solicitation does not include the SAM clause the agency collects the same data on FAR provision 52.204-3 instead. Primes, subcontractors and state purchasing offices are a separate matter, and they will ask.
Is my Unique Entity ID the same as my TIN?
They are different numbers. The Unique Entity ID is a 12-character identifier assigned inside SAM.gov, and it replaced the DUNS number in April 2022. Your TIN is an IRS number, either an EIN or an SSN. SAM holds both. Only the TIN belongs in Part I of a Form W-9.
We are a corporation. Why did a federal agency send us a 1099-NEC?
Because payments by a federal executive agency for services sit on the short list of payments reportable to a corporation. The corporate payee exception that keeps 1099s away from most incorporated vendors does not reach them, and the amount arrives in box 1a.
What is Form 8596, and do I have to file it?
You do not. The head of a federal executive agency files it, quarterly, to report contracts under IRC 6050M. Your name, address and TIN appear on it, which gives the agency a reason to care that the number in your registration is correct.
Can a federal agency apply backup withholding to contract payments?
It can, on reportable payments where it holds no valid certification, at 24% under IRC 3406. Worth knowing: the text of FAR provision 52.204-3 still warns about a 31 percent reduction in payments. That figure has not been the backup withholding rate for decades.
A state agency sent a Substitute W-9 with extra boxes. Do I have to use it?
Generally yes, if you want to be set up as a vendor. A requester may design its own form so long as it meets the substitute requirements, and state purchasing offices routinely add a vendor number field or a certification about state tax delinquency.
General information, not tax advice. This page explains a federal tax form in plain English. It is not legal, tax, or accounting advice, and W9Form.org is not affiliated with the IRS. Verify everything against the official Form W-9 page on IRS.gov and speak to a licensed professional about your own situation. How we source and review these pages.