1099ThresholdDesk / 2026 Form W-9 Solicitation, 24% Backup Withholding & CP2100 B-Notice Generator

2026 Form W-9 Solicitation, 24% Backup Withholding & CP2100 B-Notice Packet Generator

When a subcontractor or vendor refuses to provide a signed Form W-9 before payment, or when the IRS issues a CP2100 / CP2100A TIN Mismatch Notice, IRC § 3406 requires the payer to withhold 24% federal backup withholding and remit it on Form 945, or become personally liable for the unwithheld tax plus IRC § 6721/6722 penalties (up to $660 per return).

Vendor Payment Hold, Missing W-9 & IRS Penalty Exposure Inputs
Generates formal Vendor Payment Hold & IRC § 3406 Notice PDF

IRC § 3406 Check Release vs. Backup Withholding Math

Gross Pending Vendor Invoice$4,500
Mandatory 24% Backup Withholding (Form 945)-$1,080
Net Check Payable If Released Without Signed W-9$3,420

2026 IRS § 6721 (IRS Copy) + § 6722 (Payee Copy) Penalty Exposure

Combined IRS + Payee Penalty Per Return$660
Batch Penalty Across Missing-W-9 Vendors$3,300
Total Payer Audit Exposure (Withholding + Penalties)$4,380