Ireland: Revenue updates guidance on Expressions of Doubt under Full Self-Assessment

The updated guidance clarifies the scope of extended tax payment deadlines and the circumstances in which taxpayers may submit an Expression of Doubt for Income Tax, Corporation Tax and Capital Gains Tax returns. 

Irish Revenue issued eBrief No. 041/26 on 2 March 2026, announcing updates to guidance on Expressions of Doubt under the Full Self-Assessment system for Income Tax, Corporation Tax and Capital Gains Tax.

The update revises Tax and Duty Manual (TDM) Part 41A-03-00 – Expression of Doubt – Full Self-Assessment. It includes the insertion of a new paragraph 6, which clarifies that the extended due date for payment of tax, available where a taxpayer has made a genuine Expression of Doubt, applies only to the specific matter for which the doubt has been expressed.

The change reflects section 959AU(3) of the Taxes Consolidation Act 1997, introduced by the Finance Act 2025. Under this provision, the due date for the payment of tax must be determined independently in the case of a second or subsequent assessment. In such circumstances, the tax due does not benefit from the extended due date provided under section 959AU(2) and instead reverts to the original payment deadline.

The revised guidance also updates paragraph 4 to include material previously contained in a footnote. It clarifies that Expressions of Doubt do not apply where a chargeable person is uncertain whether a person they engage should be treated as employed or self-employed.

Under the Full Self-Assessment system, taxpayers may submit an Expression of Doubt where they have a genuine uncertainty about how the law applies to a matter included in an income tax, capital gains tax or corporation tax return. The mechanism allows taxpayers to notify Revenue of their uncertainty regarding the correct tax treatment of an item.

Revenue notes that before submitting an Expression of Doubt, taxpayers must consult all relevant guidance, including manuals and published guidelines available on the Revenue website, in an effort to determine the appropriate treatment of the issue in question.