Why has my contractor deducted 30% CIS?

Why has my contractor deducted 30% CIS? Because HMRC told your contractor to. In October 2026, 30% applies when you are not registered for CIS or the contractor's verification did not match your registration, often over a name or UTR difference. Usually because HMRC could not match the details your contractor gave when verifying you. GOV.UK says you get 20% only if you are registered and the contractor can verify you. The name, UTR and National Insurance number must exactly match your registration. Not on their own. They must re-verify you, or receive a notice from HMRC of your new status. Once HMRC confirms 20%, it applies to payments from then on. No. The contractor has paid it to HMRC. HMRC's manual says the form telling contractors about a changed status advises them not to refund deductions already made. You get the credit from HMRC. Read the full answer, with every source, at rightotax.co.uk.