Construction Industry Scheme (CIS): 2026 Practical Guide

The Construction Industry Scheme is a UK tax regime requiring contractors to check, deduct and report tax on certain payments to subcontractors carrying out construction work. For 2026, contractors and subcontractors should carefully review their CIS position, particularly in light of HMRC’s updated CIS 340 guidance and the new rules from 6 April 2026 on nil returns and payments to subcontractors that are local authorities or public bodies.

Key Aspects of Construction Industry Scheme

The Construction Industry Scheme applies to contractors and subcontractors involved in construction operations in the UK. Its purpose is to ensure that tax is accounted for at source where subcontractors are paid for construction work.

Under CIS, a contractor must decide whether a payment falls within the scheme, verify the subcontractor where required, apply the correct deduction rate and report the payment to HMRC. The subcontractor then receives a payment and deduction statement, which supports their claim for tax already deducted.

The standard CIS deduction rates are:

Subcontractor CIS status	CIS deduction rate	Practical impact
Registered subcontractor paid under deduction	20%	Contractor deducts tax from the labour element before payment
Unregistered or unmatched subcontractor	30%	Higher deduction applies, often creating a cash-flow disadvantage
Gross payment status approved by HMRC	0%	Subcontractor is paid without CIS deductions

WellTax can assist contractors and subcontractors in reviewing whether their current CIS process applies the correct rates, especially where payments include labour, materials, VAT and project expenses.

Construction Industry Scheme registration requirements

Contractors are required to register under the Construction Industry Scheme if they pay subcontractors for construction work. Companies that operate as both contractors and subcontractors may need to register in both capacities.

Unlike contractors, subcontractors are not legally required to register under CIS. However, a subcontractor that chooses not to register, or whose details cannot be verified by HMRC, may suffer the higher deduction rate of 30%. For this reason, CIS registration is usually commercially important for subcontractors.

Contractors not primarily involved in construction may still need to register as deemed contractors if their construction expenditure exceeds £3 million in the previous 12-month period. HMRC’s guidance confirms that businesses must monitor construction spend regularly, and once the £3 million threshold is exceeded, relevant payments within CIS must be reported.

Once HMRC accepts a contractor’s registration, HMRC provides reference details, including the PAYE Employer Reference and Accounts Office Reference. For subcontractors, the Unique Taxpayer Reference, or UTR, is a key reference used for registration and verification.

Where an overseas business carries out construction work in the UK, CIS may still apply. For wider UK project considerations, see WellTax’s article on tax considerations for foreign entities operating a building site in the UK.

Subcontractor verification under CIS

Before making a payment to a subcontractor for work within CIS, a contractor must check whether the subcontractor needs to be verified with HMRC. Verification is the process through which HMRC confirms the deduction rate that should apply.

A contractor may not need to verify a subcontractor again if that subcontractor has already been included on a CIS return in the current tax year or the previous two tax years. If the subcontractor is new, or has not been included within that period, the contractor should verify the subcontractor before making payment.

Information needed for verification

Before processing payment, the contractor should make sure it holds the correct information needed to verify the subcontractor with HMRC. The details required will depend on the contractor’s own registration position and the subcontractor’s legal structure.

For a sole trader subcontractor, HMRC may require:

• Name.
• UK Taxpayer Reference number (UTR).
• National Insurance number.

For a company subcontractor, HMRC may require:

• Business name.
• Business UK Taxpayer Reference number (UTR).
• Business registration number.

For a partnership, HMRC may require details of the firm and partner, including UTR or company registration details depending on the partner’s status.

Verification result

Once the verification is completed, HMRC will confirm whether the subcontractor should be paid:

• Gross, with no CIS deduction.
• Net of the standard deduction rate.
• Net of the higher deduction rate because HMRC cannot verify the subcontractor or has no registration record.

HMRC will also provide a verification reference number. This is particularly important where the higher deduction rate applies, as it must be recorded and shown on relevant payment and deduction statements.

Contractor responsibilities under CIS

Contractors have continuing monthly obligations under the Construction Industry Scheme. These obligations apply after registration and continue for each relevant CIS reporting period.

The CIS reporting period runs from the 6th of one month to the 5th of the next. The contractor must submit the monthly return to HMRC by the 19th of the following month. For example, the return for the period 6 May to 5 June is due by 19 June.

The monthly return must report payments made to subcontractors and deductions made from those payments. As a result of these obligations, contractors make two separate payments: one to the subcontractor, who uses it to partially settle their invoice, and another payment to HMRC, also due by the 19th of the following month. Contractors must also provide payment and deduction statements to subcontractors where deductions have been made.

Failure to comply with CIS can lead to penalties, interest and contractor exposure for under-deducted tax. A practical CIS process should therefore be built into supplier onboarding, invoice approval and payment release, rather than left until the return deadline.

New 2026 Construction Industry Scheme guidelines

HMRC’s 2026 CIS 340 guidance confirms two important new guidelines from 6 April 2026. Contractors should update their CIS reporting and payment processes where they work with public bodies or where no subcontractor payments are made during a reporting period.

Payments to public bodies

From 6 April 2026, payments to subcontractors that are local authorities or public bodies fall outside the scope of CIS. Although these bodies may still be subcontractors in principle when carrying out construction operations for someone else, contractors should not verify them under CIS, apply CIS deductions to their payments or include those payments on CIS monthly returns.

This change is important in practice because it affects how public body subcontractors are set up and processed in contractor payment systems.

Nil returns for mainstream contractors

From 6 April 2026, mainstream contractors that make no payments to subcontractors during a CIS reporting period must either submit a nil return to HMRC or notify HMRC of a period of inactivity. If they do neither, a penalty may apply.

Work covered by the Construction Industry Scheme

The Construction Industry Scheme applies to a broad range of construction operations. The scope is wider than many businesses expect, particularly where a contract includes both construction and non-construction elements.

Work commonly covered by CIS includes:

• Construction of permanent or temporary buildings and structures.
• Civil engineering works, including roads, bridges, railways and power lines.
• Site preparation, including laying foundations and access works.
• Demolition and dismantling.
• Traditional building tasks.

• Alterations, repairs and decorative work.
• Installation of systems for heating, lighting, power, water and ventilation.

Certain activities are generally outside CIS when supplied independently, including:

• Architecture and surveying services.
• Scaffolding hire without labour.
• Carpet fitting.
• Manufacture of building materials, plant or machinery.
• Delivery of materials.
• Non-construction site services, such as operating a canteen.

Mixed contracts require careful review. Where a single contract includes both construction operations and non-construction services, the full payment may fall within CIS, even if the construction element is minor or shown separately on the invoice.

For construction businesses, this is one of the most important parts of CIS compliance. Incorrectly treating covered work as outside CIS can create under-deduction risk for the contractor.

Gross payment status

A subcontractor may apply to HMRC for gross payment status. If approved, contractors can pay the subcontractor without CIS deductions. This can improve cash flow for subcontractors, but it also places importance on maintaining a strong compliance record.

Gross payment status is not automatic. HMRC will consider whether the subcontractor meets the relevant business, turnover and compliance tests. If the subcontractor’s tax compliance position changes, HMRC may withdraw gross payment status after giving notice.

Construction Industry Scheme registration for foreign companies

Where an overseas business carries out construction work in the UK, Construction Industry Scheme may still apply. Foreign companies should assess their CIS registration position before starting work in the UK. The registration process can take up to six weeks, so businesses should allow enough time before making or receiving CIS payments.

Registration forms

The form required depends on whether the overseas company is registering as a contractor, a subcontractor or both. Contractor registration is completed through Section 1 of the CIS registration form. Subcontractor registration requires Section 2 of the CIS registration form, together with form CIS305.

Supporting information

• Provide the original certificate of pending charges issued by the tax authority in the company’s home country.
• Complete form 64-8 if an agent will act on behalf of the company.

CIS deductions and refunds

Where a foreign company does not hold gross payment status and CIS deductions are applied, it may be able to claim a refund after the end of the tax year. The refund claim is made online and should include the total CIS deductions suffered during that tax year.

UK land and Corporation Tax registration

A foreign company that deals in or develops UK land may also be subject to UK tax on its profits. It must notify HMRC and register for tax as a company or individual, as applicable. To register for Corporation Tax, the company should write to HMRC with the relevant registration details.

• The address of the company’s registered office.
• The date to which the annual accounts are made up.
• The date the company started dealing in or developing UK land, which will usually mark the start of its first accounting period.
• The company’s country of tax residence.
• The company’s country and date of incorporation.

Benefits of the Construction Industry Scheme

Although CIS is often viewed as an administrative burden, it can provide practical benefits when managed correctly. The scheme gives contractors and subcontractors a clearer framework for tax deductions and reporting in an industry where payment chains can be complex.

The main benefits include:

• Reduced tax leakage, because deductions are made at source before subcontractor payments are released.
• Clearer payment records, because contractors must issue deduction statements where CIS tax is withheld.
• Advance tax credit for subcontractors, as deductions can be set against their tax liabilities.
• Improved transparency between contractors, subcontractors and HMRC.
• Online management of registration, verification and returns.
• Better discipline around subcontractor onboarding and payment controls.

For subcontractors, CIS deductions can help spread tax payments during the year, although they may also create short-term cash-flow pressure. For contractors, the benefit is mainly procedural: a well-managed CIS process reduces the risk of unexpected liabilities, missed returns and supplier disputes.

Construction Industry Scheme Compliance checklist for 2026

Contractors and subcontractors should review CIS compliance regularly, especially where business models, project types or subcontractor relationships change.

Area	Contractor action	Subcontractor action
Registration	Register before paying subcontractors where CIS applies	Register to avoid higher deductions where relevant
Verification	Verify new or inactive subcontractors before payment	Provide accurate legal name, UTR and registration details
Deduction rate	Apply HMRC-confirmed rate	Check deduction statements against invoices and bank receipts
Monthly returns	File by the 19th after each tax month	Keep CIS statements for tax return or company records
Materials and VAT	Calculate deductions on the correct amount	Show labour, materials and VAT clearly on invoices
2026 update	Exclude qualifying local authority and public body subcontractor payments from CIS	Confirm status where relevant before payments are processed

A practical review should ask:

1. Is the contractor correctly registered for CIS?
2. Has the subcontractor been verified where required?
3. Is the work within the CIS definition of construction operations?
4. Has the contractor correctly identified labour, materials and VAT?
5. Is the CIS return aligned with payment records?
6. Have any 2026 public body changes been applied correctly?
7. Has a nil return been submitted, or has HMRC been notified of inactivity, where no subcontractor payments were made during the CIS reporting period?
8. Has the CIS monthly return been filed by the 19th of the following month?
9. Are CIS deductions reconciled with subcontractor statements, accounting records and HMRC payments?

Where CIS overlaps with payroll or employment status, contractors should also consider whether PAYE obligations may arise.

Final thoughts

The Construction Industry Scheme remains a key compliance area for contractors and subcontractors in 2026. The main risks are practical ones: missed registration, incomplete subcontractor verification, incorrect deduction rates, poor materials records, late monthly returns and uncertainty over whether specific work falls within CIS.

A well-managed CIS process supports clearer reporting, stronger payment controls and better tax compliance. It also helps contractors and subcontractors reduce avoidable errors, improve transparency and maintain more reliable financial records.

For contractors, subcontractors and overseas businesses working on UK construction projects, WellTax can assist with CIS registration, deduction reviews, monthly reporting and wider UK tax compliance.

Written by Michele Ammirati, Managing Partner at WellTax and UK Chartered Accountant