Keep the contractor’s CIS payment and deduction statements for each tax month in which deductions were taken. They show the gross payment, relevant materials and tax withheld. If one is missing, request it and tell the accountant which period needs reconciling.
When you should receive it
A CIS tax month runs from the 6th of one month to the 5th of the next. The contractor must give you the statement within 14 days after the end of that tax month — so typically by the 19th. They may issue one statement covering the whole month or one per payment, as long as you get at least the required monthly evidence where deductions were taken.
HMRC notes there is no obligation to issue a statement where payment was made gross (no deduction), though some contractors still do as good practice.
What it should show
Statements can look different, but CIS 340 expects details such as:
- contractor name and employer tax reference
- tax month end date (or payment date if single-payment statements)
- your name and Unique Taxpayer Reference (UTR)
- verification number if higher-rate (30%) deductions were made because you could not be verified
- gross amount of payments
- cost of materials that reduced the amount subject to deduction
- amount of the CIS deduction
Why it matters for your tax return
On Self Assessment you report income before CIS and claim the deductions as a credit. The monthly statements are how you build those year totals. They also help you spot a wrong 20% vs 30% rate early. For reclaim mechanics see CIS deductions on Self Assessment and CIS tax refunds.
If the statement never arrives
- Ask the contractor in writing for the missing tax month(s).
- Cross-check bank receipts and your own job records so you know what “should” appear.
- Keep chasing — HMRC’s guidance puts the duty on the contractor to provide the statement when deductions were made.
- Tell your accountant which months are missing before the return is filed; do not invent figures.
Practical filing habit
Save PDFs or photos in folders by tax month (6th–5th), not by calendar month alone. One missing January statement can wipe hundreds of pounds of CIS credit if nobody notices until January filing season. Pair this with the wider Self Assessment documents checklist.
Those statements also help you total gross CIS labour for the year. If that gross self-employment income (with any property income) may sit above Making Tax Digital thresholds, keep the same figures tidy for eligibility checks — check if MTD applies — without treating CIS paperwork as an MTD filing by itself.
TaxSimba’s Self Assessment accountants will ask for a complete set of statements before preparing a CIS-heavy return. We cannot issue statements for a contractor, and we do not guarantee HMRC will accept incomplete evidence. Start Self Assessment with TaxSimba when you want help turning the paperwork into a correct return.
If the contractor cannot supply duplicates
HMRC’s current route is to write to PT Operations, HM Revenue and Customs, BX9 1BX. Include your name, address and UTR; the contractor’s name and address; its tax reference if known; payment dates or tax months; and why statements or duplicates are unavailable.
Check the official missing-statement instructions before posting, and retain a copy. Requesting evidence does not itself confirm the deduction amount or extend a return deadline.
Request a named missing period
Illustrative preparation example.
Write to the contractor identifying the tax month, payment dates and statement required. Keep the request and response. If duplicates cannot be obtained, use HMRC’s published missing-statement route rather than inventing deductions by reversing the bank payment.
Check: Which statement is missing, what has been requested and what evidence is available instead?
| Check | Practical action |
|---|---|
| Which tax month and contractor are missing? | Build a month-by-contractor grid so gaps are visible. |
| Do statement totals match actual payments? | Reconcile gross amounts, relevant materials, deductions and net receipts. |
| Can the contractor supply a replacement? | Request it first and retain the request; use HMRC's official alternative if unavailable. |
Can a bank credit prove the deduction?
It proves receipt of money, but not necessarily the CIS amount. Obtain the statement or follow the missing-evidence route.
Are CIS tax months calendar months?
No. They run from the 6th to the following 5th. Label files by the tax month so statements are not accidentally omitted or counted twice.
Download a checklist for this guide
- List contractors and CIS tax months.
- Match each statement to bank payments.
- Mark missing, duplicate or disputed amounts.
- Request replacements and keep correspondence.
- Tell your accountant about unresolved gaps before filing.