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When you need a new W‑9, even if you already have one
A signed W‑9 does not expire. But it goes stale: vendors change names, entities and addresses, and sometimes the IRS tells you the form you have on file is wrong. Here are six situations where an existing W‑9 needs a check or a replacement, and which of them come with a real deadline.
1. The IRS flags a mismatch Required, on a deadline
If the name and TIN you file on a 1099 do not match IRS records, the IRS sends you a CP2100 or CP2100A notice. First compare the notice against your own records; if yours turn out to be wrong, you usually just correct them. If they match, you send the vendor a first "B" notice together with a fresh Form W‑9. Under IRS Publication 1281, that notice goes out within 15 business days of the date of the CP2100 or the date you received it, whichever is later.
If the vendor does not return a signed W‑9, you must begin backup withholding - holding back 24% of each payment and remitting it to the IRS - no later than 30 business days after that same date. When the vendor sends their signed W‑9, you stop withholding no later than 30 calendar days after receiving it.
A vendor listed on a CP2100 a second time within three calendar years gets a second "B" notice, and a new W‑9 is no longer enough. The validation the vendor owes you depends on their TIN type: a copy of their Social Security card for an SSN, or an IRS Letter 147C for an EIN.
If you file 1099s, the IRS also offers a TIN matching e-service that checks a name and TIN pair against its records before filing season. It is optional, but it catches mismatches early, before they become CP2100 notices.
2. The vendor's entity changes
A sole proprietor becomes an LLC or an S-corp. A company is acquired or merges. Changes like these can alter the legal name, TIN or tax classification, and the classification decides whether the vendor needs a 1099 at all, since payments to most corporations are exempt (with exceptions, such as attorney fees). The change itself does not automatically invalidate the form on file: review whether the vendor's tax identity or classification actually changed, and if it did, obtain an updated W‑9.
3. Name, address or ownership changes
Even small changes make the old W‑9 stale. The 1099 goes to the wrong address, or the name you report no longer matches what the vendor files.
4. Payment details change Good practice
A common vendor-fraud pattern is an email from a "vendor" asking to update bank details. Many AP teams re-verify the W‑9 as part of any change to payment details, so the legal name and TIN still match the entity they think they are paying.
Worth being clear about what this check does and does not do: a W‑9 confirms the vendor's identity for tax purposes, but it says nothing about who owns a bank account. Verify bank changes separately, for example by calling a known contact on a number already on file.
5. The IRS revises the form Good practice
The IRS updates Form W‑9 from time to time. The current revision (March 2024) added line 3b for certain flow-through entities with foreign partners, owners or beneficiaries. A signed W‑9 does not expire when the form is revised; older signed W‑9s generally remain valid. Re-collecting on a new revision is housekeeping, not a deadline, but some companies do it anyway. (A new revision is in the works - see what changed in 2026.)
6. Audit hygiene Good practice
Many teams re-collect every two to three years, or once a year before 1099 season, so the form on file is recent and signed. Again a practice, not a requirement - the old forms have not expired - but a cheap one compared to a CP2100.
When the new W‑9 comes back
Whatever triggered the re-collection, give the fresh form a quick check before you file it away:
- Legal name. It should match what the IRS has on file. For a sole proprietor, that is the owner’s name on line 1, with the business name on line 2.
- TIN type. The number should fit the entity: an SSN or the owner’s EIN for a sole proprietor or disregarded single-member LLC, the entity’s own EIN for a corporation or partnership.
- Classification. One federal tax classification box checked, with exemption codes only where they actually apply.
- Signature and date. Signed under penalties of perjury. Keep the superseded form too, so your records show when the details changed and why.
The short version
You do not need a new W‑9 every year. You need one fast when the IRS flags a mismatch, and you need one whenever the old form's details actually change: a new name, TIN, classification or address. The hard part was never knowing this; it is chasing the vendor until the signed form actually comes back.
Re-collecting W‑9s this season?
Paperhound chases every vendor, verifies each W‑9 and posts it to your books. Done for you, and you pay only for completed W‑9s.
Get in touchThis article is general information, not tax advice. For your situation, talk to your tax advisor.