Reporting & compliance
Backup Withholding & the W-9 at Closing
A slow-to-return W-9 is a purely administrative reason funds get withheld at closing.
What it is
As part of closing, a buyer, platform, or escrow agent typically requests a signed Form W-9 from a US seller to confirm their taxpayer ID. Without a valid one on file, backup withholding — a flat percentage withheld from proceeds — can apply.
Why it matters for a secondary
A seller slow to return a signed W-9 can end up with funds withheld rather than paid out in full at closing — an entirely avoidable delay if handled early rather than at the last minute.
Quick facts
- Form required from a US seller
- W-9
- Form required from a non-US seller
- W-8BEN instead — see cross-border wire & tax reporting
- Backup withholding if W-9 missing or invalid
- A flat statutory percentage — confirm the current rate
Common mistake: Leaving the W-9 request until the day of closing, adding an avoidable delay to receiving full proceeds.
Frequently asked questions
When should I submit my W-9?
As early as possible once a deal is agreed — well before the ROFR window even closes — so it's not the item holding up the escrow release.
Is backup withholding the same as normal tax withholding?
No — it's a separate, punitive-rate withholding specifically triggered by a missing or invalid taxpayer ID, not the standard tax treatment of the gain itself.
Is this tax or legal advice?
No. This is independent educational content, not investment, tax, or legal advice. Tax law and thresholds change; confirm your specific situation with a qualified advisor before acting on it.