Section 991 Interest
(1) Where an amount of tax which an employer is liable under this Chapter and any regulations under this Chapter to pay to the Revenue Commissioners is not so paid, simple interest on the amount shall be paid by the employer to the Revenue Commissioners, and such interest shall be calculated from the expiration of the period specified in the regulations for the payment of the amount until payment—
(a) for any day or part of a day before 1 August 1978 during which the amount remains unpaid, at a rate of 0.0492 per cent,
(b) for any day or part of a day on or after 1 August 1978 and before 1 April 1998 during which the amount remains unpaid, at a rate of 0.0410 per cent,
(c) for any day or part of a day on or after 1 April 1998 and before 1 July 2009 during which the amount remains unpaid, at a rate of 0.0322 per cent, and
(d) for any day or part of a day on or after 1 July 2009 during which the amount remains unpaid, at a rate of 0.0274 per cent.
Amendments
Subs (1) substituted by Finance Act 2009 section 29(1)(g) as respects any unpaid tax or duty, as the case may be, that has not been paid before 1 July 2009 regardless of whether that tax or duty became due and payable before, on or after that date.
(1A) Notwithstanding anything in subsection (1) but subject to subsection (1B), where an amount of tax (in this subsection referred to as "the relevant amount") in respect of a year of assessment (being the year of assessment 2000-2001 or a subsequent year of assessment) is paid later than 14 days after the end of that year of assessment, interest in accordance with subsection (1) shall be payable and calculated―
(a) where the relevant amount does not exceed 10 per cent of the total amount of tax which the employer was liable under this Chapter and any regulations made under this Chapter to pay to the Revenue Commissioners for that year of assessment, as if the due date for payment of the relevant amount was the 14th day immediately following the end of the year of assessment, and
(b) where the relevant amount exceeds 10 per cent of the amount so payable, as if the due date for payment of the relevant amount was―
(i) as respects the year of assessment 2000-2001, 31 October, 2000,
(ii) as respects the year of assessment 2001, 30 September, 2001, and
(iii) as respects the year of assessment 2002 and subsequent years of assessment, 31 July in the year.
Amendments
Subs (1A) inserted by Finance Act 2001 section 237(b).
(1B) Where, within 1 month of interest being demanded by the Collector-General in accordance with subsection (1A), the employer declares in writing to the Collector-General the amounts of tax which he or she was liable to remit, but had not remitted, for each of the income tax months comprised in the year of assessment, interest shall be calculated and payable in respect of those amounts in accordance with subsection (1), without regard to subsection (1A).
Amendments
Subs (1B) inserted by Finance Act 2001 section 237(b).
How is interest calculated where a monthly return is made within one month of receiving an interest demand?
(1B) If you file the monthly PAYE returns for a tax year within one month of receiving an interest demand mentioned in (1A), the interest must be calculated by reference to the returns (and not on the basis mentioned in (1A)).
(2) This section shall apply―
(a) to tax recoverable by virtue of a notice under section 989 as if the tax were tax which the person was liable under the regulations to pay for the respective income tax month or months referred to in the notice, and
(b) to tax recoverable by virtue of a notice under section 990 as if the tax were tax which the person was liable under the regulations to remit for the last income tax month of the year of assessment to which the notice relates.



