Corporation Tax Act 2010 section 357TC

Northern Ireland supplementary deduction: amount

Section 357TC provides the formula for calculating the amount of the Northern Ireland supplementary deduction that a qualifying company can claim in respect of its Northern Ireland trading activity.

• The supplementary deduction is calculated using a formula based on the Northern Ireland additional deduction, less any losses surrendered, scaled by the difference between the main corporation tax rate and the Northern Ireland rate
• The key inputs are: the Northern Ireland additional deduction for the period, any Northern Ireland losses surrendered under section 1217CH of CTA 2009, the main corporation tax rate, and the Northern Ireland rate
• Where an accounting period straddles two financial years, a separate calculation is performed for each financial year and the results are time-apportioned according to the proportion of the accounting period falling in each year
• The time-apportioned amounts for each financial year are then added together to give the total supplementary deduction for the accounting period