Glossary · Tax

Aggregation: plain-English guide for Irish probate

The rule that every taxable gift or inheritance from the same CAT group since 5 December 1991 is added together before the group threshold is applied.

Updated April 2026. Plain-English guide for Irish executors, administrators, and beneficiaries.

What it means, in plain English

Aggregation is the CAT rule that adds every taxable gift or inheritance a beneficiary has received from the same group since 5 December 1991. The running total is tested against the group threshold. This is what makes small historic gifts matter years later: a €50,000 wedding gift from a parent in 1998 reduces the threshold headroom on an inheritance in 2026.

Aggregation in Irish probate practice

The rule is set out in Schedule 2 to the Capital Acquisitions Tax Consolidation Act 2003. Aggregation applies within each CAT group separately: Group A gifts and inheritances aggregate together, Group B together, Group C together. A parent's gift and a stepmother's gift both aggregate into the same Group A total. Certain items do not aggregate: the €3,000 Small Gift Exemption per donor per year, transfers between spouses, and specific exempt benefits such as funds for educational support. Prior gifts that qualified for a relief at the time (Dwelling House Exemption, Business Relief, Agricultural Relief) still aggregate at their relieved value. The 5 December 1991 start date was set by the CAT reform legislation and has remained since. The practical consequence for executors is that every beneficiary needs to be asked about any significant prior gifts or inheritances before the SA2 and IT38 can be accurately completed. This is one of the most common places CAT filings go wrong: beneficiaries forget, or did not realise, that a decade-old wedding gift counts.

Worked example

Eoghan received a €75,000 gift from his mother in 2009 to help buy his first house. The Small Gift Exemption of €3,000 applied to €3,000 of it, so €72,000 was a taxable Group A gift. Eoghan filed the IT38 at the time but no tax was payable because his running total was well under the threshold. In 2026, his mother dies and leaves him €380,000. For CAT purposes, his Group A running total is now €72,000 plus €380,000, equals €452,000. The Group A threshold is €400,000. His taxable amount is €52,000, taxed at 33%, for CAT of €17,160.

The statutory position

Schedule 2 of the Capital Acquisitions Tax Consolidation Act 2003 sets out aggregation rules. Section 45 covers prior-benefit reporting on the IT38 return. The 5 December 1991 start date is fixed and applies to every beneficiary.

Related terms in this glossary

  • CAT (Capital Acquisitions Tax): The Irish tax on gifts and inheritances, charged at 33% on the value of a beneficiary's inheritance above their applicable group threshold.
  • Small Gift Exemption: An annual CAT exemption of €3,000 per donor per beneficiary, usable every calendar year without eroding the lifetime group threshold.
  • Valuation date: The specific date CAT uses to fix the value of an inherited asset; usually the date of the Grant of Probate, but subject to specific rules for different asset types.
  • IT38 return: The Revenue return a beneficiary files when their gift or inheritance takes them above 80% of the applicable CAT group threshold.

Related reading

How ProbatePack handles Aggregation

Everything in the Preparation Pack plus the full inheritance-tax layer. CAT calculator for each beneficiary, individual IT38 drafts, Dwelling House Exemption assessment, Section 72 check, Agricultural and Business Relief assessments where applicable, and the Revenue clearance letter. For estates that will cross the Group A threshold.

Get the Complete Probate Bundle for €449

This glossary entry is general preparation guidance, not legal or tax advice. For complex estates, contested wills, or situations involving significant tax structuring, consult a solicitor or tax adviser.