The corporation tax rates for small and large companies will be aligned at 20% from April 2015. This will remove the need for the associated companies rule and the marginal rate of corporation tax will disappear. The rates for the three financial to 31 March 2016 have been announced as:
| Year beginning 1 April: | 2013 | 2014 | 2015 |
| Small profits rate (profits up to £300,000) |
20% | 20% | 20% |
| Marginal rate (profits in band £300,000 to £1.5 million) |
23.75% | 21.25% | N/A |
| Main rate for companies (profits above £1.5 million) |
23% | 21% | 20% |
Different rates apply to profits from North Sea oil and gas.
Banks pay a special bank levy in addition to these rates of corporation tax.