
Backup Withholding in 2026: When 24% Applies, How to Avoid It With Valid W-9s, and the CP2100 Notice Response
Backup withholding is 24% flat on reportable payments when the TIN is missing or the CP2100 says it is wrong — cured by a W-9 before payment and two B-notices within 15 business days, reported on Form 945.










