Some 13 of Ireland’s top 100 companies pay an effective rate of tax of just 1 per cent, the latest Comptroller and Auditor General (C&AG) report has found.
The low rate, which is significantly below the State’s headline rate of 12.5 per cent, reflects the impact of various tax credits and reliefs available to companies operating in the State.
The report indicated that within the top 100 companies the average tax rate paid in 2015 varied significantly.
While 79 companies paid an effective rate of 10 per cent or more, almost two-thirds paid rates in excess of 12 per cent.
Ireland’s corporate tax rate, which is the lowest in the OECD, has been at the centre of international debate over multinational tax avoidance.
The C&AG's report cited recent research by PwC and the World Bank, which suggested Ireland's estimated effective rate of corporation tax was 12.4 per cent, just 0.1 per cent below the statutory rate.
It noted that 12 OECD countries had an effective rate of corporation tax that was lower than this, while 21 had a higher effective rate.
In 2015, the US had the highest statutory rate of corporation tax in the OECD at 39 per cent, coupled with the second-highest effective rate of 28.1 per cent. France had the second-highest statutory rate at 38 per cent but the lowest effective rate at just 0.4 per cent.
The C&AG’s report also highlighted the fragility of the State’s corporate tax base, with 37 per cent of receipts coming from just 10 firms and 70 per cent from the top 100.
It noted that corporate tax receipts jumped by 49 per cent to €6.9 billion in 2015 amid a massive transfer of multinational assets here, and that the tax base now represented 15 per cent of the Government’s total tax take.
This was the seventh-highest in the EU and the sixth-highest of OECD countries in 2015.
The report also indicated that 70 per cent of corporate tax here came from just three sectors of the economy: financial and insurance activities; manufacturing (including pharmaceutical manufacturing); and information and communications.
“Corporation tax receipts are highly concentrated both in terms of sectors and by number of taxpayers,” the report said.
It also echoed a warning by the Department of Finance that the reliance on a small cohort of large corporation taxpayers was a risk that needed to be "carefully managed".