How to Request a W-9 From a Sub or Vendor

When to request a W-9

The IRS’s own word for it is the initial solicitation, and it belongs at the start: when you open the account or the first job is agreed, before any money moves. That timing isn’t a nicety. If a sub hasn’t given you a taxpayer identification number (TIN) when you first ask, you’re expected to start backup withholding on reportable payments to them, and for payments for services that applies straight away, even if they’ve written “Applied For” where the number goes.

Ask again, with a fresh W-9, when:

• The sub’s name, entity or TIN changes: a sole proprietor forms an LLC, an LLC elects S-corp tax treatment, a company is bought. A W-9 describes one taxpayer; a new one is a new form.
• The IRS tells you the name and TIN don’t match (a CP2100 or CP2100A notice). The first “B” notice you send the sub goes out with a blank W-9 for exactly this.
• The address changes. The W-9 says to write “NEW” above a changed address, and it’s where you’ll mail the 1099.
• The form on file is an old revision or is missing a line you need. The March 2024 revision added line 3b and clarified how a single-member LLC fills in line 3a, which is where older forms most often go wrong.

Asking at onboarding also changes the conversation. In March, the sub wants the job and sends the form the same day. In January, you’re asking for paperwork about money they’ve already been paid, and the 1099 deadline is January 31.

What a complete W-9 looks like

Check the form when it arrives, not when you file. The current revision is Form W-9 (Rev. March 2024); these are the lines that get sent back most often:

The classification on line 3a decides more than it looks: it’s how you know whether the sub gets a 1099 at all. Payments to a corporation, including an LLC taxed as one, generally don’t go on a 1099-NEC. The W-9 for an LLC guide walks through the cases.

A W-9 request email you can send

Short, specific about why, and clear about how to send it back. Replace the bracketed parts:

If you collect the certificate of insurance and license at the same time, ask for all three in one request: one message is far more likely to be answered than three. How to get subcontractors to send COIs covers the follow-up schedule.

Getting it back safely

A completed W-9 is a name, an address and a Social Security or employer identification number on one page. Treat it the way you’d treat a bank detail form:

• Don’t ask for it as an email attachment. It ends up in inboxes, sent folders and forwarding chains you don’t control. Use an upload page or a secure link.
• You can take it electronically, including by fax, under the IRS’s rules for electronic submission in the requester instructions. When the form doesn’t have to be signed, the system doesn’t have to provide an electronic signature either.
• Keep it; don’t send it anywhere. The W-9 stays with you. You use it to file the 1099; it never goes to the IRS.
• Limit who can see the TIN. Whoever prepares the 1099s needs it; the project team doesn’t.

When a sub won’t send one

You can’t make anyone fill in a form, but the IRS spells out what you do next, and it’s worth telling the sub, because it usually ends the delay:

• Backup withhold. With no TIN, you withhold 24% from reportable payments to them and send it to the IRS, reported on Form 945. If you’re required to withhold and don’t, you may become liable for the amount you didn’t collect. See backup withholding.
• Ask again in writing, on schedule. To avoid a penalty for filing a 1099 without a TIN, the IRS expects a first annual solicitation by December 31 of the year the account was opened (January 31 if it was opened in December), and a second by December 31 of the following year.
• Keep a record of every ask: the date, how it was sent and what was asked for. That record is what shows you did what was required.

Most subs send it the moment they understand that a quarter of each check is otherwise going to the IRS. Saying so in the second request is not a threat; it’s the rule.