The short answer
Form W-9 at closing is the settlement agent's request for the seller's correct taxpayer identification number, certified under penalties of perjury, so it can file Form 1099-S reporting the sale. The IRS instructions require the request no later than closing and the signed form kept for four years. If you hold title through a single-member LLC, the W-9 carries your name and number rather than the LLC's, and the same form can double as your FIRPTA non-foreign certification.
At a glance
| Who asks | The person responsible for closing, usually the settlement agent |
|---|---|
| Deadline | The TIN must be requested no later than the time of closing |
| Backup withholding | Real estate transactions are not subject to it |
| Disregarded entity | Owner's name and TIN on line 1, entity name on line 2 |
The request comes from the Form 1099-S reporting rules.
The Instructions for Form 1099-S make a sale or exchange reportable even if it is not currently taxable, so an exchange is reported. The filer must request the transferor's TIN no later than closing, may use Form W-9 for U.S. persons and Form W-8 for foreign persons, and must keep the form for four years. Multiple transferors each get a separate Form 1099-S, based on an allocation requested at or before closing; a partnership gets one form.
Form W-9 itself says real estate transactions are not subject to backup withholding, and for real estate you must sign the certification but may cross out item 2. For a disregarded entity with a U.S. owner, the owner's name goes on line 1 and the entity's name on line 2; a foreign owner uses Form W-8 instead. Under Reg. section 1.1445-2(b)(2)(v), a valid W-9 also serves as a certification of non-foreign status.
A hypothetical: one building, three sellers, three different W-9s.
Hypothetical figures: a $1,500,000 building is sold by three owners. You hold one-third through your single-member LLC, your sister holds one-third in her own name, and a two-member LLC taxed as a partnership holds the rest. The closer asks each for a W-9 and an allocation.
Your W-9 shows your name and Social Security number on line 1 and the LLC's name on line 2, so your Form 1099-S reports $500,000 to you. Your sister's form reports $500,000 to her. The partnership gives its own EIN and receives one form for its $500,000, not one per partner. Each owner's return must then explain its share: on Form 8824 if exchanged, on the sale forms if not. Run your own numbers with your CPA.
It bites when the number on the form is not the taxpayer doing the exchange.
The exchange is claimed by the taxpayer whose TIN the IRS matches to the 1099-S. If an LLC wrongly gives its own EIN, the form may land on a return that reports no sale, which prompts the IRS matching letters described in Form 1099-S and the 1031 exchange. Match the W-9 to the taxpayer who will take title to the replacement, as the same-taxpayer rule requires.
The instructions also allow a filer reporting a like-kind exchange with no reportable gross proceeds to enter zero in box 2a and check box 6. Ask the settlement agent how it will report your sale, and sign the FIRPTA affidavit in the same name.
Related questions
Can I refuse to give a W-9 at closing?
The instructions say the transferor is required to furnish a complete TIN and certify it, and the suggested request warns of civil or criminal penalties for not doing so. Refusing does not stop the reporting.
Which number goes on a W-9 for my single-member LLC?
The owner's. The W-9 instructions say a disregarded single-member LLC enters the owner's SSN, or the owner's EIN if the owner has one, and the IRS encourages individual owners to use the SSN. The LLC's name goes on line 2.
Does the W-9 make my exchange taxable?
No. It only identifies who sold. Whether gain is deferred is shown on your Form 8824; see whether you can do a 1031 through an LLC.
Sources
Checked against these publications on September 30, 2026. Rules and figures change; confirm the current version with your CPA or attorney before you act. This page is general information, not tax or legal advice.