Guide
CIS nil returns - when you must file and when you don't
When you must submit a CIS nil return and when you can avoid monthly filing. Covers current rules allowing inactivity periods, the April 2026 change requiring nil return OR advance notification, and how to prepare for the transition.
As a CIS contractor, you must tell HMRC about payments to subcontractors every tax month. But what if you did not pay anyone? This guide explains when you need to file a nil return, when you can request an inactivity period instead, and how rules are changing from April 2026.
Many contractors are confused about nil return requirements - and this confusion has led to unnecessary penalties. Understanding your options now will help you avoid problems, especially as the rules are about to change.
What is a nil return?
A nil return is a CIS monthly return showing that you made no payments to subcontractors during that tax month. It tells HMRC that you are still an active contractor but had no subcontractor activity in that period.
Without either a nil return or an inactivity request, HMRC assumes you have failed to report payments you have made - which triggers automatic penalties.
Current rules (until 5 April 2026)
Under current rules, you have two options when you have not paid any subcontractors in a tax month:
Option 1: Submit a nil return
File a CIS return showing zero payments. The deadline is the same as for any other return:
Option 2: Request an inactivity period
If you expect no subcontractor payments for an extended period, you can ask HMRC to set your CIS account to inactive. During an inactivity period:
- You do not need to submit monthly returns (nil or otherwise)
- HMRC will not expect returns from you
- You will not receive late filing penalties for not filing
- Inactivity can last up to 6 months at a time
How to request inactivity
Contact HMRC's CIS helpline or write to them to request an inactivity period. You will need to provide:
- Your contractor UTR and Accounts Office reference
- The date you want inactivity to start
- How long you expect to be inactive (up to 6 months)
- The reason for inactivity (seasonal work, no current projects, etc.)
Critical requirement during inactivity
If you make ANY payment to a subcontractor during an inactivity period, you must:
- Contact HMRC immediately to end the inactivity period
- Submit a CIS return for that tax month by the 19th
- Pay any deductions by the 22nd (electronic) or 19th (postal)
Failing to notify HMRC when you make payments during inactivity is treated as a missed return - you will receive the full late filing penalty.
The April 2026 change - new filing requirements
From 6 April 2026, the rules are changing significantly.
Why is this changing?
The current inactivity system has caused widespread confusion:
- Contractors forgetting to notify HMRC when they start paying subcontractors again during an inactivity period
- Uncertainty about obligations - many contractors unsure whether they needed to file nil returns or request inactivity
- HMRC losing sight of contractor activity - the relaxed rules made it harder to track which contractors were genuinely inactive
- Accidental non-compliance - contractors receiving unexpected penalties when inactivity periods expired
The new system simplifies the position: for each month with no subcontractor payments, you either file a nil return OR notify HMRC in advance that you will not be making payments. The 6-month inactivity period system is being replaced with simpler monthly advance notification.
Comparing current and future rules
| Situation | Before 6 April 2026 | From 6 April 2026 |
|---|---|---|
| No subcontractor payments this month | File nil return OR request inactivity | File nil return OR notify HMRC in advance |
| No subcontractor payments for 3 months | Request inactivity period | File nil return OR notify HMRC each month |
| Seasonal construction work (summer only) | Request 6-month inactivity for winter | File nil return OR notify each winter month |
| Forgot to file or notify | Penalty unless inactivity was requested | Penalty (must do one or the other) |
| Want to stop being a CIS contractor | Request to be taken off CIS register | Request to be taken off CIS register |
What you should do now
With the April 2026 change approaching, take these steps:
-
Check your current CIS status
Sign in to HMRC online services and check whether your CIS account is active or set to inactive. If inactive, note when the period ends.
-
Review your filing habits
If you have been relying on inactivity periods, you will need to change your process from April 2026. Set monthly reminders to file returns.
-
Update your calendar
Add recurring reminders for the 19th of each month (return deadline) and 22nd (payment deadline). Filing consistently avoids penalties.
-
Consider payroll software
Software that handles CIS can automate nil returns when there are no payments to report. This removes the risk of forgetting to file.
-
Decide if you should deregister
If you genuinely no longer use subcontractors and have no plans to, consider asking HMRC to remove you from the CIS contractor register entirely.
Penalties for missed nil returns
The penalty structure for missed nil returns is the same as for any other late CIS return:
- 1 day late: Fixed penalty of 100 pounds
- 2 months late: Additional 200 pounds (300 pounds total)
- 6 months late: Additional 300 pounds or 5% of deductions due, whichever is greater
- 12 months late: Further penalty up to 100% of deductions due
For nil returns (where no deductions are due), the percentage-based penalties do not apply - but you will still face the fixed penalties of up to 600 pounds per return.
If you miss multiple nil returns, each attracts its own penalty. Missing 6 monthly nil returns could cost you 600 pounds in fixed penalties.
Appealing a nil return penalty
If you receive a penalty for a missed nil return, you can appeal if you have a reasonable excuse. Valid excuses include:
- Serious illness preventing you from filing
- Death of a close family member
- HMRC online service failure (if documented)
- Disaster affecting your records or ability to work
However, these are not accepted as reasonable excuses:
- Not knowing about the filing requirement
- Being too busy with other work
- Thinking you did not need to file because you had no payments
- Forgetting the deadline
- Relying on someone else to file for you
You have 30 days from receiving a penalty notice to appeal. If you miss this deadline, you must explain why your appeal is late.
Deregistering as a CIS contractor
If you no longer pay subcontractors and have no plans to do so, you can ask HMRC to remove you from the CIS contractor register. This is different from requesting inactivity - it means you are no longer a CIS contractor at all.
To deregister:
- Contact HMRC's CIS helpline
- Confirm you no longer use subcontractors for construction work
- Provide your contractor UTR and Accounts Office reference
Once deregistered, you have no CIS filing obligations. However, if you later start paying subcontractors again, you must re-register as a CIS contractor before making any payments.
Important: Deregistration as a contractor does not affect any subcontractor registration you may have. If you work as both a contractor (using subcontractors) and a subcontractor (working for other contractors), these are separate registrations.
Common questions
Do I need to file a nil return if I am a subcontractor only?
No. Nil returns are only required from contractors - businesses that pay subcontractors. If you only work as a subcontractor, you have no return obligations (though you must ensure contractors verify you and deduct correctly).
What if I become a contractor mid-year?
You must file returns from the tax month in which you register as a contractor. If you register in October but do not pay any subcontractors until January, you must file nil returns for October, November, and December.
Can I still request inactivity before April 2026?
Yes, you can request inactivity periods until 5 April 2026. However, any inactivity period will automatically end on 6 April 2026 when the new rules come into force. Plan accordingly.
What if my inactivity period spans April 2026?
Your inactivity will end on 5 April 2026. From 6 April 2026, you must either file nil returns OR notify HMRC in advance each month. HMRC should contact you about this change, but do not rely on receiving a reminder - mark the date in your calendar.
Seasonal construction businesses
If your construction work is seasonal (for example, outdoor work that stops in winter), the April 2026 change affects you.
Currently, you can request inactivity for your off-season. From April 2026, the 6-month inactivity period option ends - you must either file nil returns for winter months OR notify HMRC in advance each month that you will not be making payments.
Consider setting up automated reminders or using payroll software that handles nil returns automatically.