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Understanding the impact of the Corporation Tax rate increase

Currently all companies pay Corporation Tax at the rate of 19%.

From April 2023, there will two rates of Corporation Tax.

  • The main rate of tax will be 25% for Companies with profits of £250,000 or more – 25% will apply to all profits

  • A Small Profits Rate of 19% will apply to Companies with profits of £50,000 or less

  • There will be taper relief available for Companies with profits between £50,000 and £250,000

Whilst we have not yet seen the detailed rules on how taper relief will be calculated, commentators are fairly certain that the calculation will be substantially the same as that used pre-2015, the last time the UK tax system had two rates of Corporation Tax. The final details will be set out in the 2022 Finance Act.

Understanding the impact of Taper Relief 

This is going to take a little bit of understanding both by businesses and accountants that have not seen taper relief before. Technically Corporation Tax will apply as follows

  • If profits exceed £250,000, the main rate of 25% will apply to all profits

  • If profits are £50,000 or less the Small Company rate of 19% will apply to all profits

  • Where profits are between these thresholds, the main rate of 25% will apply with the company being entitled to Marginal Small Companies Relief (MSCR)

Marginal Small Companies Relief (MSCR)

MSCR tapers the effect of the increased rate on a company where profits are between the lower and upper thresholds.

The MSCR calculation is:

(Upper Limit – Profits) x Basic profits x MSCR fraction where the



  • Upper Limit is £250,000

  • Basic profits are the company’s trading profits / gains

  • Profits are Basic Profits plus Franked Investment Income (FII is generally Dividends received from other companies)

  • MSCR Fraction is 3/200ths 

 The MSCR is the difference between the main rate and marginal rate of Corporation tax expressed as a fraction, so 26.5%-25% = 1.5% = 3/200

For those with a headache already, there is a simpler expression that will accurately work out the Corporation tax due, where there is just basic profit to tax (and no FII).

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Applying these bands will give the same result as applying the formula given above and are much easier to use. Let us prove it to you.

A company has basic profits of £125,000 and no FII.  Applying the complex formula,

As profits are over £50,000 Corporation tax is charged at 25%

Corporation tax due £125,000 x 25% = £31,250

MSCR can then be applied using the complex formula

(£250,000 - £125,000) X £125,000 X 3/200 = £1,875


Net corporation tax due is £31,250 - £1,875 = £29,375


We obtain the same result applying the simplified rates in the table to profits of £125,000

Up to £50,000 @ 19%                         £9,500

£125,000 -£50,001 @ 26.5%              £19,874.73

Total tax payable £29,375

Marginal Rates and Effective Rates

It is important to understand the difference between the Marginal rates and Effective Rates of tax. The headlines will report a Marginal Rate of 26.5%, implying that some businesses are paying beyond the Main rate of Corporation tax at 25%, but this isn’t the case.

Companies with profits between £50,000 and £250,000 will pay a Marginal rate of Corporation tax of 26.5% on profits within that bracket but their effective rate of tax will be less than 26.5%.

Take a company with profits of £150,000 and applying the flat table rates,

The first £50,000                     Taxed at 19%               £9,500

The next £100,000                  Taxed at 26.5%            £26,500

Total tax payable                                                        £36,000

Whilst the Company has a marginal rate of 26.5% it’s overall effective rate of tax is 24% (£36,000/£150,000). This £36,000 is the same result as charging the whole £150,000 profits at 25% and applying the MSCR.

The effective rate of Corporation tax applies to the whole of the Company’s profits and at no point exceeds the main rate at 25%.


The effective rate at various profit levels will be








Effective CT %







Multiple Company Rules – watch out!

Where there are associated Companies the £50,000 and £250,000 thresholds will be apportioned. This includes companies not based in the UK and means that the Main Rate of Corporation Tax applies sooner. The upper and lower limits will be proportionately reduced for short accounting periods.

Associated companies are those where:

  • One has control of the other; or

  • Both are under common control


Where associated companies exist, the thresholds are apportioned. A group with two companies will see the upper and lower limits divided by two, meaning the profit level at which a marginal rate will apply could be more easily breached.

There are a number of exclusions from the associated company rules:

  • Dormant companies are excluded from the associated company rules

  • Where a “passive” holding company exists a company will not be treated as an associate of another. A “passive” holding company is one where a company only receives dividends from its subsidiaries and pays these to its shareholders, and the company receives no other income or expenses.

  • Where companies are under common control but the relationship between one or more companies is not one of “substantial commercial interdependence” they will not be treated as associated for the purpose of the new rules

For example, husbands and wives are connected parties for tax. On the face of it, a company run by Mr A will be associated with a company run by Mrs A.  However, if Mr A is the director and sole shareholder of Company A which operates a shoe shop and his wife runs a restaurant through Company B, the nature of the two businesses is completely different commercially. Provided there are also no financial or economic links between the companies, and they are organisationally independent, they are not associated for these purposes.

With the Corporation tax rules becoming more complex its vital you seek advice from your accountant to plan ahead. Orange Genie Accountancy clients have access to a dedicated accountant who over the coming months will be looking at how the Corporation Tax changes will affect their businesses.


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