The Scenario That Most IR35 Guides Miss

Most IR35 guidance assumes you have one limited company and one contract at a time. It treats you as either inside or outside IR35 on a single contract, and the advice stops there.

But what if you are a contractor running your own limited company for IT consultancy work, and you also own a separate limited company that runs a café in Manchester's Northern Quarter? Or you take outside-IR35 contracts through your personal service company while your wife runs a separate ecommerce business through another Ltd you both own?

This is where ir35 explained for the real world gets complicated. HMRC looks at the whole picture, not just one contract in isolation. Get the structure wrong and you could trigger an IR35 enquiry, lose your outside-IR35 status, or create tax liabilities you did not see coming.

As ICAEW qualified accountants, we see this situation more often than you might expect. Here is how to handle it properly.

Does Having a Separate Limited Company Affect Your IR35 Status?

Short answer: not directly. But it creates risks if you are not careful.

IR35 is about the relationship between you and your client. If your contract is genuinely outside IR35, having a separate trading company does not automatically pull you inside. HMRC cannot argue you are a disguised employee of the café you own. That is a real business.

The risk comes from how you operate. If your contractor Ltd and your trading company share a bank account, mix expenses, or have unclear ownership structures, HMRC may argue that the two entities are effectively one. That weakens your outside-IR35 defence.

Think of it this way. Your outside-IR35 contract relies on showing HMRC that you are in business on your own account. If you also run a café through a separate Ltd, that actually strengthens your case. It proves you are a genuine business owner, not a disguised employee. But only if you keep the two companies distinct.

How HMRC Views Multiple Limited Companies

HMRC does not automatically treat multiple companies as associated. But they can be if certain conditions apply. Associated companies are those under common control, meaning the same person or group of persons controls both.

If you control your contractor Ltd and your trading company, they are associated. That matters for corporation tax because the associated company rules affect the profit bands for the small profits rate and marginal relief.

For corporation tax 2025/26, the small profits rate of 19% applies to profits up to £50,000. But that £50,000 threshold is divided by the number of associated companies. So if you have two associated companies, the threshold drops to £25,000 each. Profits between £25,000 and £125,000 per company then attract marginal relief up to the main rate of 25% at £125,000.

Here is a worked example. Your contractor Ltd makes £40,000 profit. Your café Ltd makes £30,000 profit. Without the associated company rule, both would pay 19% on all profits. With two associated companies, the 19% band is £25,000 each. Your contractor Ltd pays 19% on the first £25,000 and marginal relief on the next £15,000. Your café Ltd pays 19% on the first £25,000 and marginal relief on the next £5,000. The total corporation tax bill is higher than you might have budgeted for.

This is not an IR35 issue directly, but it is a cost of running multiple companies that many contractors miss.

IR35 Status Determination: One Contract at a Time

IR35 applies to each engagement separately. Having an outside-IR35 contract with Client A does not protect your inside-IR35 contract with Client B. And having a separate trading company does not change the IR35 status of any individual contract.

What matters is the terms of each contract and the working practices in practice. For your outside-IR35 contracts, you need to demonstrate:

  • Substitution: you can send a replacement if you cannot do the work yourself
  • Control: the client does not control when, where or how you work
  • Financial risk: you are responsible for fixing mistakes at your own cost
  • Equipment: you provide your own tools and equipment
  • Part and parcel: you are not integrated into the client's organisation

Your separate trading company does not help or hinder these factors. But it does demonstrate that you are a genuine business owner with multiple income streams. That can help HMRC see you as a contractor, not an employee.

The Practical Risks of Mixing Two Companies

The biggest risk is sloppy record keeping. If you use the same bank account for both companies, or transfer money between them without proper documentation, HMRC can argue the companies are not genuinely separate.

Here are the specific risks:

  • Directors loan account confusion. If your contractor Ltd lends money to your trading company without a formal loan agreement and proper interest, HMRC can treat it as a distribution. That means dividend tax, not a loan repayment.
  • Mixed expenses. Claiming expenses that relate to one company against the other is a red flag. HMRC will disallow them and potentially open a full enquiry.
  • Shared assets. If you use the same laptop for both companies, you need a clear basis for claiming capital allowances. You cannot claim 100% on the same asset twice.
  • VAT complications. If one company is VAT registered and the other is not, transactions between them need proper VAT invoices. HMRC will check.

A client of ours ran an outside-IR35 contract through his Ltd while also owning a separate Ltd that ran a property portfolio. He paid for property repairs from his contractor Ltd bank account, calling it a director's loan. The loan was never formalised. When HMRC opened an IR35 enquiry on his contract, they found the mixed accounts and argued that his contractor Ltd was not a genuine business. The enquiry took 14 months to resolve. He paid £8,400 in professional fees to fight it.

Can You Pay Yourself From Both Companies?

Yes, but the tax treatment is different for each.

From your contractor Ltd (outside-IR35 contracts), you pay yourself a salary and dividends in the normal way. The salary is subject to PAYE and NI. Dividends come from post-tax profits.

From your trading company, you do the same. But the combined picture matters for your personal tax position.

Your personal allowance is £12,570 for 2025/26. If both companies pay you a salary, the total salary is added together. If you take £10,000 from the contractor Ltd and £10,000 from the café Ltd, that is £20,000 total salary. The first £12,570 is tax-free. The remaining £7,430 is taxed at 20% basic rate.

Dividends from both companies are also combined. The £500 dividend allowance applies to your total dividend income across all sources, not per company. Dividends above £500 are taxed at 8.75% basic rate, 33.75% higher rate, or 39.35% additional rate depending on your total income.

This means you need to coordinate your pay strategy across both companies. Taking maximum dividends from both could push you into the higher rate tax band unnecessarily.

Should You Have One Company or Two?

This is the fundamental question. Many contractors set up a second company for a side business without considering whether one company could do both.

There are legitimate reasons for two companies:

  • One business has significant liability risk (e.g. construction) and you want to ringfence it
  • One business is VAT registered and the other is below the threshold
  • You have a business partner in one venture but not the other
  • You plan to sell one business separately and want to use BADR (Business Asset Disposal Relief)

But there are also costs. Two sets of accounts, two corporation tax returns, two confirmation statements. Two sets of filing fees. More complex payroll. And the associated company rule that reduces your corporation tax thresholds.

If your second business is a small side venture, it may be simpler to run it through your existing contractor Ltd. Just make sure the contract work and the side business are properly ringfenced in your accounts. Use separate nominal codes. Track income and expenses separately. Consider a separate bank account for the side business even within the same company.

If you do keep two companies, make sure they are genuinely separate. Separate bank accounts. Separate VAT registrations if applicable. Separate payroll. Clear intercompany loan agreements if money moves between them.

IR35 Enquiry Risk With Multiple Companies

HMRC uses data matching. If your contractor Ltd files a CT600 showing low salary and high dividends (typical outside-IR35 pattern), and your trading company shows a different pattern, HMRC may flag both for review.

The risk is not that HMRC finds your outside-IR35 contract is actually inside. The risk is that HMRC opens an enquiry into one company and finds issues in the other. That can trigger a full enquiry across all your entities.

If HMRC opens an IR35 enquiry on your contractor Ltd, they will ask for:

  • All contracts and working practices evidence
  • Bank statements for the company
  • Director's loan account statements
  • Details of all other income sources

If your other company appears in those records without proper documentation, the enquiry widens. That costs time and money.

The best defence is clean records. Keep separate bank accounts. Document all intercompany transactions. Have a clear dividend policy for each company. And make sure your outside-IR35 contracts are genuinely outside, with proper contracts and working practices to back them up.

Practical Steps to Protect Yourself

  1. Use separate bank accounts. This is non-negotiable. Each company needs its own business bank account. No transfers between them without formal loan agreements.
  2. File separate accounts on time. Late filing at Companies House attracts penalties starting at £150 for a private company. Two companies means double the risk.
  3. Keep separate payroll records. Even if you use the same payroll software, each company must have its own PAYE reference and RTI submissions.
  4. Document intercompany loans. If one company lends to the other, use a formal loan agreement with commercial interest. Repay within 9 months and 1 day of the year-end to avoid S455 tax (33.75% on the loan amount).
  5. Review your associated company status. If you control both companies, tell your accountant. They need to calculate corporation tax correctly using the associated company rules.
  6. Keep outside-IR35 contracts properly documented. Use a contract review service for each new engagement. HMRC can look back 6 years on IR35 enquiries.
  7. Consider professional indemnity insurance. If one company has a claim, the other company's assets should not be at risk. Proper separation helps.

When to Speak to an Accountant

If you already have two companies or are thinking of setting up a second one, speak to a qualified accountant before you act. The associated company rules, IR35 implications, and personal tax planning need to be worked through together.

We handle this regularly for contractors in Manchester, London, Bristol and across the UK. If your situation involves an outside-IR35 contract alongside a separate trading company, contact us to discuss the structure that works for you.

For a full overview of IR35, including status determination tests and contract review tips, see our IR35 fundamentals guide. And if you are thinking about restructuring, our incorporation page covers the key considerations.