Taxes Consolidation Act 1997 section 959Y

Chargeable persons and other persons: assessment made or amended by Revenue officer

Section 959Y sets out the general power of a Revenue officer to make or amend a Revenue assessment or a self assessment for any chargeable period.

• A Revenue officer may at any time make a Revenue assessment in such amount as, in the officer's best judgement, ought to be charged on the person.
• A Revenue officer may amend a Revenue assessment or a self assessment even where tax has already been paid or repaid, and even where the assessment has been amended on one or more previous occasions.
• In making or amending an assessment, a Revenue officer may accept in whole or in part the particulars contained in a return and may assess income, profits, gains or chargeable gains, or allow any allowance, deduction, relief or tax credit by reference to those particulars.
• Where any amount is omitted from, or not properly reflected in, an assessment, or the tax stated is less than the tax payable, the officer may amend the assessment to correct it, including by adding amounts not previously reflected.