UK Corporation Tax Planning in 2025: Rates, Structures, and Offshore Comparisons

The Current UK Corporation Tax Rate Structure

The UK's corporation tax rate structure was fundamentally changed by the Finance Act 2023, which increased the main rate from 19% to 25% from 1 April 2023. The current structure:

Main rate: 25% on taxable profits above £250,000 Small profits rate: 19% on taxable profits below £50,000 Marginal relief: A taper between £50,000 and £250,000 that produces an effective marginal rate of 26.5% on profits in the marginal band

The marginal rate of 26.5% — higher than the 25% main rate — is a deliberate structural feature of the marginal relief system. It arises because the relief is withdrawn progressively as profits rise, creating a band where the effective rate on additional profits exceeds 25%.

Marginal Relief Calculation

Marginal relief is calculated as:

Marginal Relief = Standard Fraction × (Upper Limit − Augmented Profits) × (Taxable Total Profits ÷ Augmented Profits)

Where:

• Standard Fraction = 3/200 (effectively the 6 percentage point difference between 25% and 19%, divided over the £200,000 marginal band)
• Upper Limit = £250,000
• Lower Limit = £50,000
• Augmented profits = taxable profits plus exempt distributions from associated companies

For a company with £150,000 of taxable profits and no associated companies:

Profit Level	Tax Calculation	Effective Rate
£50,000	£9,500 (19%)	19%
£100,000	£21,500 (using MR)	21.5%
£150,000	£34,250 (using MR)	22.8%
£200,000	£48,500 (using MR)	24.3%
£250,000	£62,500 (25%)	25%
£300,000	£75,000 (25%)	25%

The Associated Companies Rules

The £50,000 and £250,000 thresholds are divided by the number of associated companies (plus one for the company itself). Two companies under common control means each has a lower limit of £25,000 and an upper limit of £125,000.

The associated companies rules were rewritten by Finance Act 2023 and now apply a broader definition of association based on control tests similar to the old "associated company" rules pre-2015. Two companies are associated if one controls the other, or both are controlled by the same person or group.

Impact for Group Structures

A UK trading company with three associated subsidiaries (total of four companies in the group) has thresholds of £12,500 (lower) and £62,500 (upper). The main rate applies from £62,500 — the small profits rate benefit is minimal.

For holding company structures with multiple entities, the associated companies rules mean the benefit of the small profits rate is quickly eroded. Consolidating income streams or restructuring to reduce the number of associated companies may be worth considering.

R&D Tax Credits: The New Merged Scheme

The UK's R&D tax credit regime was merged from April 2024, replacing the separate SME and RDEC schemes with a single merged scheme:

• All companies (SME and large) can claim an enhanced deduction of 186% of qualifying R&D expenditure
• Loss-making SMEs with intensity above 30% of total expenditure in R&D qualify for an enhanced credit rate of 14.5% (rather than 10%)
• The pre-notification requirement introduced in 2023 (notifying HMRC of an intention to claim within 6 months of the accounting period end) continues to apply

UK vs Offshore Corporation Tax Comparison

For businesses operating internationally, the question of UK incorporation vs offshore incorporation involves a comparison of effective rates, compliance costs, and banking access:

Jurisdiction	Corporate Rate	Dividend WHT to Non-Residents	Key Benefit
UK	19–25%	0% (no domestic WHT on dividends)	Treaty network, banking, EU passporting pre-Brexit
Ireland	12.5% (trading)	25% (treaty reduced)	EU membership, US treaty, English-speaking
Cyprus	12.5%	0%	Non-dom SDC exemption, low cost
Malta	35% (35% refunded to shareholders)	0% (after refund)	EU member, effective 5% for foreign income
UAE	9% (above AED 375,000)	0%	No personal tax, free zones at 0%
Singapore	17% (with exemptions, effective 4.25% for new companies)	0% (one-tier system)	Asia-Pacific hub
Cayman Islands	0%	0%	Fund domicile, no corporate tax

When Offshore Incorporation Is Worth the Substance Cost

The shift from UK to offshore incorporation is only beneficial where:

1. The effective rate differential exceeds the substance cost. A UAE company at 9% saves 16 percentage points over the UK main rate. On £500,000 of profit, that is £80,000 per year. Against a substance cost (Registered Address, qualified director, local advisory, compliance) of £15,000-25,000 per year, the net benefit is significant. On £100,000 of profit, the net benefit may be negligible.

2. The business can genuinely operate offshore. A business where management and control is exercised in the UK — where the directors, decisions, and staff are UK-based — is UK resident for corporation tax purposes under the central management and control test (De Beers Consolidated Mines v Howe [1906] AC 455), regardless of where the company is incorporated.

3. The UK CFC rules do not attribute profits back to the UK. TIOPA 2010 Part 9A subjects controlled foreign company profits to UK corporation tax at the main rate where the profits are artificially diverted from the UK. A subsidiary established in a low-tax jurisdiction that genuinely operates there is outside the CFC charge. One that exists primarily to hold UK-connected profits is caught.

Planning Strategies for UK Companies

Associated Company Optimisation

Review whether all associated companies are necessary. A dormant holding company that is associated with the trading company reduces both companies' marginal relief thresholds. If the holding company serves no commercial purpose, consider striking it off to restore full marginal relief thresholds to the trading entity.

Dividend Extraction Timing

The interaction of the 25% corporation tax rate with the 8.75%/33.75% dividend tax rate means the combined effective rate on corporate profits extracted as dividends by a higher-rate taxpayer is approximately 50.3%. At the basic rate, the combined rate is approximately 34.6%. Timing distributions to years when the shareholder's income is lower can reduce the overall burden.

Salary vs Dividend Optimal Mix

For owner-managed businesses, the optimal salary level to extract from the company (to benefit from employment allowances and personal allowance while minimising NIC) remains broadly £12,570 per year (the personal allowance), with additional income extracted as dividends up to the higher-rate threshold.

HPT Group advises UK businesses on corporation tax structuring, group reorganisations, and the cost-benefit analysis of offshore holding structures. With the 25% main rate now firmly in place, the economics of offshore restructuring for larger profitable businesses have shifted significantly compared to the pre-2023 position. For a current rate analysis and restructuring review, contact our UK corporate tax team or apply for a consultation.