Section 357JA | Profits chargeable to corporation tax and rates
From legislation.gov.uk
(1)The reference in section 35 of CTA 2009 (charge to tax on trade profits) to the profits of a trade is, where a company carrying on a trade in an accounting period has Northern Ireland profits of the trade or mainstream profits of the trade, a reference to those Northern Ireland profits or mainstream profits.
(2)Northern Ireland profits are charged to corporation tax at the Northern Ireland rate.Section 3(1) of this Act (corporation tax charged at main rate) has effect subject to this subsection.