Taxes Consolidation Act 1997 section 959AA

Chargeable persons: time limit on assessment made or amended by Revenue officer

Section 959AA imposes a four-year time limit on Revenue making or amending tax assessments, and sets out the circumstances in which that limit does not apply.

• Where a return contains a full and true disclosure of all material facts, Revenue cannot make or amend an assessment more than four years after the end of the chargeable period in which the return was delivered
• After the four-year window closes, no additional tax is payable and no tax is repayable by reason of any matter contained in the return
• Revenue may amend an assessment outside the four-year limit in specified circumstances, including incomplete disclosure, appeal determinations, post-return events, calculation errors, and factual mistakes
• Revenue may also make or amend an assessment at any time to give effect to a mutual agreement procedure reached under a double taxation agreement or a tax information exchange agreement