Construction Industry Scheme: at a glance
- What do I need to know? The Construction Industry Scheme (CIS) requires contractors to deduct a percentage from subcontractor invoices to act as an advance tax payment.
- What does it mean for me? CIS comes with compliance obligations and can create cash flow challenges for contractors and subcontractors.
- Why does it matter? Cash flow forecasting and high-interest business savings accounts can help you manage your cash reserves and avoid disruption.
If you work in construction, you'll know that understanding the Construction Industry Scheme (CIS) is essential for staying compliant, avoiding penalties, and keeping your business running smoothly.
Under this scheme, HM Revenue & Customs (HMRC) requires contractors to deduct money from their subcontractors’ invoices as an advance tax payment. And with changes introduced from 06 April 2026, it’s worth getting up to speed.
In this guide, you’ll learn about the CIS, the requirements for contractors and subcontractors, and how you can prepare for potential cash flow challenges.
What is the Construction Industry Scheme (CIS)?
The Construction Industry Scheme (CIS) requires contractors to withhold tax from payments to subcontractors and pass it to HMRC on their behalf.
HMRC introduced the CIS in an effort to combat tax evasion and non-payment by subcontractors in the construction industry.
You can check the details on the GOV.UK website to find out whether you need to register as a contractor or subcontractor.
How does CIS work?
Under the CIS, contractors deduct a percentage from subcontractor invoices for construction projects. They then pay this amount directly to HMRC, which counts towards the subcontractor’s tax and National Insurance.
CIS payments
Before calculating the amount to pay to HMRC, the contractor makes any appropriate deductions. These are calculated on the invoice amount after removing certain allowable costs, like VAT or the cost of any materials purchased specifically for the project. HMRC provides the exact rates and guidance on GOV.UK.
The contractor deducts either 20% of the remaining invoice amount if the subcontractor is registered with the CIS, or 30% for unregistered subcontractors. Registering with the CIS is optional for subcontractors, but those who don’t register face a higher deduction rate, which can impact short-term cash flow (more on this later).
Subcontractors claim the CIS deduction when filing their annual tax returns. Find out how you can claim as a limited company or an agent on the GOV.UK website.
Understanding contractor and subcontractor responsibilities
The CIS can present unique challenges for both contractors and subcontractors. Understanding your responsibilities – and managing your cash reserves accordingly – can help you stay compliant and navigate potential cash flow pressures.
CIS contractor considerations
If you’re a contractor, you must register with the CIS. Responsibilities involve verifying subcontractors, making CIS payments, and maintaining accurate records. You’ll need to file CIS returns with HMRC by the 19th of the following tax month, and provide subcontractors with a payment and deduction statement (PDS).
These requirements can create additional admin for finance teams or business owners. And failure to comply with CIS regulations could result in reputational damage and financial penalties.
Cash flow forecasting
CIS responsibilities can also impact cash flow forecasting for contractors. You’ll need to maintain visibility over how much money the business is holding back from invoices, as well as when payments to HMRC are due. CIS deductions must reach HMRC by the 22nd of the following month if paid electronically, or the 19th by post.
As your business scales, the more projects and subcontractors you take on, the greater the admin burden can become.
Holding cash reserves in instant access business savings accounts can let you earn interest on these funds until payments to HMRC are due.
CIS subcontractor considerations
For subcontractors, the CIS can represent an even more significant cash flow challenge. You could receive less than your invoice amounts for each project, creating short-term cash flow pressures that could impact staff, supplier, material, and other operating costs.
Registering with the CIS can help limit the impact of these cash shortfalls – reducing the advance tax deduction from 30% to 20% for each project.
A more proactive cash management approach can also help cover these future gaps. Keeping cash in high-interest savings accounts can offer a way to earn interest while maintaining flexibility for operational expenses.
Gross payment status
Some subcontractors may also be eligible for gross payment status (GPS). This status allows you to receive full payment from contractors, with no CIS deductions. You account for your own tax and National Insurance directly with HMRC.
To qualify for GPS, you must meet certain requirements relating to your business, tax payment history, and annual turnover. You can check the full details on the GOV.UK website to find out if you’re eligible and how to apply.
Changes to CIS in 2026
HMRC introduced a number of changes to the Construction Industry Scheme on 06 April 2026. These updates aim to simplify administrative processes, reduce the risk of non-compliance, and detect fraud.
Mandatory nil returns
Contractors who make no subcontractor payments in any given month must notify HMRC by the 19th of the month in the form of a nil return. Failing to do so could result in a financial penalty.
You can notify HMRC in advance if you have no projects scheduled, and even apply to make your CIS status inactive for six months to limit monthly reporting responsibilities.
Enhanced fraud intervention
From 06 April 2026, HMRC strengthened its powers to combat fraud related to the CIS. This increased authority allows HMRC to act immediately, with stricter penalties, when it deems construction firms to have committed or knowingly supported fraudulent activity.
HMRC can remove a subcontractor’s gross payment status (GPS) and apply penalties where a business knew or should have known about instances of tax evasion. The waiting period before a business can reapply for GPS has increased from one year to five. HMRC can also charge penalties of up to 30% to companies, directors, or other individuals connected to the business.
Public sector exemptions
From 06 April 2026, payments to local authorities and certain public bodies fall outside of the CIS entirely. This means contractors no longer need to apply CIS deductions to those payments.
Frequently asked questions about the Construction Industry Scheme
Is CIS registration mandatory?
CIS registration is mandatory for contractors. It’s optional for subcontractors, but registering means you get access to the lower 20% deduction rate rather than 30%.
Does CIS offer tax benefits?
The CIS isn’t a form of tax relief, and it doesn’t reduce your tax bill. But meeting your responsibilities accurately and on time can help you avoid financial penalties and help you maintain strong client relationships.
For subcontractors, registering can reduce your deduction rate from 30% to 20%, meaning more of each invoice stays with you. And gross payment status could mean no deduction at all.
What is a CIS tax refund?
Subcontractors who have paid too much tax or National Insurance could be eligible for a CIS refund. You can claim a refund on the GOV.UK website.
Managing cash flow amid CIS responsibilities
CIS requirements can create cash flow challenges for contractors and subcontractors, leaving you with less liquid capital than anticipated. And failure to meet your CIS responsibilities can lead to financial penalties and reputational damage.
But with the right preparation, they don't have to catch you off guard. Effective cash flow forecasting and proactive cash management can help you meet both compliance and financial requirements without disruption. Some businesses choose to hold their reserves in high-interest savings accounts to earn interest while preserving liquidity.
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