HMRC is urging contractors to regularly verify the CIS status of their subcontractors due to errors in tax deductions, reports the Institute of Chartered Accountants in England and Wales. Contractors must verify new subcontractors before payment, using HMRC’s free online service or commercial software (required for verifying over 50 subcontractors). Subcontractors not included in CIS returns for the current or previous two tax years must also be re-verified to ensure correct deductions.