Corporation Tax has become more complex in recent years, and 2026 continues that trend. For small and medium-sized businesses across the UK, understanding what’s changing and what isn’t is key to protecting profits and avoiding surprises.
Here’s a clear, practical guide from Accountants247 to what matters most.
1. Corporation Tax Rates: A Quick Refresher
Since April 2023, the UK has operated a tiered Corporation Tax system:
- 19% for companies with profits up to £50,000
- 25% for companies with profits over £250,000
- A tapered rate (Marginal Relief) between £50,000 and £250,000
For many growing SMEs, this means tax bills are higher than they were just a few years ago and careful planning is now more important than ever.
If your profits are creeping towards the £50,000 or £250,000 thresholds, 2026 could be the year where proactive tax planning makes a significant difference.
2. Associated Companies: The Rule That Catches Businesses Out
One of the biggest changes impacting SMEs is how thresholds apply when you have more than one company.
If your business has associated companies (for example, a second limited company under common control), the £50,000 and £250,000 thresholds are divided between them.
Example:
If you have two associated companies, the lower threshold becomes £25,000 each – not £50,000.
Many UK business owners don’t realise this until after their year-end. If you operate multiple companies (property + trading, separate ventures, family-owned structures), this needs reviewing urgently.
3. Capital Allowances & Investment Planning
The government has made “Full Expensing” permanent for qualifying plant and machinery purchases.
This allows:
- 100% deduction in year one for qualifying main-rate assets
- 50% first-year allowance for special rate assets
For businesses investing in equipment, vehicles (excluding most cars), machinery or technology in 2026, timing purchases correctly could significantly reduce your Corporation Tax bill.
Planning purchases before your year-end can make a material difference to cash flow.
4. Profit Extraction: Salary vs Dividends in 2026
Corporation Tax is only part of the equation. Directors also need to consider:
- Dividend tax rates
- The reduced dividend allowance
- National Insurance implications
- Personal tax thresholds
The optimal mix of salary and dividends has shifted over recent years, particularly as dividend allowances have reduced. A review before your accounting year ends can prevent unnecessary tax leakage.
5. Cash Flow Impact for Growing SMEs
At 25%, Corporation Tax is now a substantial outgoing for profitable businesses.
For example:
- £300,000 profit = £75,000 Corporation Tax liability
If you’re scaling, hiring, or reinvesting, this can catch you off guard.
Practical steps:
- Monthly tax provisioning (set aside funds as you go)
- Quarterly management accounts
- Forecasting future liabilities before major decisions
Busy SMEs often focus on turnover but tax planning must keep pace with growth.
6. R&D and Relief Changes
If your business claims R&D tax relief, the scheme has undergone significant reform in recent years, including merged schemes and revised qualifying criteria.
Incorrect or aggressive claims are now under greater scrutiny from HMRC. If you’re claiming or considering claiming professional review is essential to avoid compliance risk.
7. What Business Owners Should Do Now
With Corporation Tax at its highest rate in over a decade, reactive accounting is no longer enough. SMEs should:
- Review group structures and associated companies
- Forecast profits before year-end
- Plan capital expenditure strategically
- Revisit director remuneration strategies
- Ensure R&D claims are robust
The earlier planning starts, the more options are available.
Corporation Tax in 2026 isn’t necessarily about new headline rate changes – it’s about navigating a more complex system efficiently.
For SMEs, the difference between basic compliance and proactive planning can mean thousands of pounds saved annually.
If you’re unsure how the current rules affect your business, a mid-year review could be one of the most valuable financial decisions you make this year. Feel free to contact our friendly team today here.
