CIS deductions and subcontractor statements

CIS deduction statements should explain the payment and deduction made to the correct subcontractor. Retain the calculation and supporting invoice details, including the treatment of materials and other components under the applicable CIS rules.

Reconcile statements with monthly returns and bank payments. A net payment alone does not explain the gross amount or establish the subcontractor’s tax position.

Start with the payment being made

Identify the subcontractor, invoice or invoices covered and the amount actually being settled. Separate the commercial invoice total from the components used in the CIS deduction calculation. A partial payment, retention release or combined settlement needs an explanation of how the figures relate to the underlying work. Keep that calculation with the payment record so the statement can be reproduced without reconstructing the whole project ledger.

HMRC instructs contractors to use the verification outcome for the deduction rate and explains the components taken out before applying it, including relevant materials and VAT. Where deductions are made, the payment and deduction statement must be provided within the required period after the tax month. Follow the current calculation and statement rules for the actual transaction rather than applying a percentage to the net bank amount. ^[1]

Support materials and other components

Ask for a clear invoice breakdown and the evidence needed to assess the materials element under the applicable rules. Distinguish materials bought by the subcontractor from items supplied directly by the contractor. A line labelled 'materials' is a starting point for review, not conclusive evidence of the amount that can be excluded. Preserve the explanation where the figure differs from the invoice description or requires a supported estimate.

Check other components individually instead of treating every non-labour description as outside the deduction calculation. Equipment hire, fuel and other costs have specific treatment that should be reviewed against the facts. Record the calculation in a way another person can follow: original amount, relevant exclusions, deduction base, rate and deduction. This is more dependable than a spreadsheet containing an unexplained net total and a manually entered tax figure.

Connect the statement to the verified entity

Use the correct subcontractor identity and required references, matching the record used for verification and reporting. If the subcontractor has changed legal form, resolve that change before issuing a statement under an old record. The same trading name may describe a different taxpayer after incorporation. A statement attributed to the wrong entity can create problems even where the deduction amount itself was calculated accurately.

Send the statement through a controlled route and retain a copy with the contractor's records. Confirm the delivery details with the subcontractor and avoid sharing personal identifiers in a general project email. If statements are issued through software, check that the recipient can access their own document without seeing another subcontractor's information. The delivery process is part of completing the task, not an optional step after the calculation.

Reconcile three views of the transaction

Compare the statement with the bank payment and the monthly CIS return. The gross payment, deduction and net settlement should have a clear relationship, allowing for the specific transaction components. Investigate differences before they accumulate across several months. A subcontractor's query may reveal a statement error, a payment allocation problem or an incorrect return; establish which record is wrong before changing all three.

Keep commercial deductions, such as an agreed set-off, distinct from the CIS amount. Their effect on the payment and tax calculation needs proper assessment, and the statement should not imply that every reduction in the bank transfer was paid to HMRC. Where the contractual position is disputed, obtain the appropriate advice and preserve the correspondence. Finance should not resolve a construction payment dispute merely by changing the tax-deduction line.

Correct errors with an audit trail

If an error is confirmed, prepare the revised calculation and identify the affected statement, return and payment. Follow the appropriate correction process and tell the subcontractor what changed. Retain the original and replacement documents with clear labels. Do not silently delete an earlier statement that the subcontractor may already have used in their records or passed to their accountant.

Use Preparing a monthly CIS return for the monthly return workflow and CIS return support to discuss CIS deduction calculations and statement reconciliation. Bring one complete example showing the invoice, verification outcome, calculation, statement and bank settlement. That sequence helps locate the discrepancy without requiring an initial transfer of every subcontractor record or unrelated project document.

At the end of the tax year, ensure statement copies remain available for the required period and that unresolved queries have an owner. A deduction is an advance payment towards the subcontractor's liabilities; the statement does not establish their final tax bill or guarantee that the amount will be refunded. Keep the explanation factual when responding to requests for tax-outcome assurances.

Illustrative scenario

A subcontractor queries a deduction on an invoice containing labour and materials. The contractor reviews the supporting figures, explains the calculation and corrects any error through the proper records.

Preparation checklist

• Identify the subcontractor
• Support deduction calculations
• Issue required statements
• Reconcile returns and payments