An Irish resident company is chargeable to corporation tax on its worldwide profits and capital gains (s 21).

Corporation tax is charged for each financial year, i.e., calendar year.

Assessments are made by reference to an accounting period, and where an accounting period straddles two financial years, the profit is apportioned accordingly, to be charged at the appropriate rates (s 26).

Corporation tax is charged on the full amount of profits arising in the accounting period, whether or not such profits are received in the Republic of Ireland (ROI). Only legitimate deductions may be made (s 27).