Unsuccessful appeals by taxpayers against Revenue assessments delivered €605 million in tax to the exchequer last year, according to the Tax Appeals Commission’s annual report.Corporation tax continues to account for the lion’s share of disputed tax, accounting for €423 million of the money paid over to Revenue – 70 per cent of the tax yield from all appeals finalised – despite accounting for just 5 per cent of cases. Income tax remains the biggest single tax heading subject to appeal in terms of case numbers among the 1,192 new appeals lodged during last year but, in terms of the amount in dispute, corporation tax and capital gains tax dominated. The commission said that it receive 15 appeals in the first two weeks of January last year with a combined value of €417 million. Other cases involves just a few hundred euro.Fewer taxpayers were successful in making their case than in recent years, winning just 8 per cent of the 216 cases that went to formal determination, compared to 14 per cent last year and 19 per cent the year before. However, in money terms, there was much less between taxpayer and Revenue, with the latter’s success in securing €19 million of tax only modestly ahead of the €13 million in favour of taxpayers.The bulk of the 1,286 cases closed during the year were either withdrawn by the taxpayer (346) or settled (464). Overall, the commission scheduled 237 hearings during the year. “Operationally, 2025 was another successful year for the Commission,” said chairwoman Marie-Claire Maney. She said the number of appeals outstanding at year end – 620 – was the lowest since the commission had been established in 2016.“As the Commission receives circa 1,200 appeals each year, this figure demonstrates about six months’ work in progress, which is a remarkable figure for any decision-making body,” she said, noting that the increasing complexity of the appeals over multiple tax heads and referencing European law continued to be a trend in 2025.The Government is currently ushering legislation through the Oireachtas that would give the commissioner hearing a tax appeal discretion to determine whether they should be open to the public by default. And outside “special and limited circumstances”, all decisions of those hearings would identify the taxpayers involved.At present, while the default is that hearings before the Tax Appeals Commission are held in public, if a taxpayer requests a behind-closed-doors hearing, they must be accommodated, with any outcome of such hearings anonymised. In practice, all hearings are held in private.The Government proposal has been strongly criticised by industry groups, including the Irish tax Institute and Chartered Accountants Ireland, who say that it will deter people from making appeals against what they consider to be unfair tax assessments.Tax professionals say that one in five appeals over the four years up to 2025 had been successful, highlighting the value of the current system, and that the process was useful in determining the treatment of increasingly complex tax law.An Oireachtas committee examining the legislation last week recommended that the Government reconsider its position, saying that taxpayers exercising their right to challenge an assessment should continue to have the right to have their hearings held in private.