99.—(1) Subject to subsections (2) and (3), where in relation to a return lodged under Chapter 3 of Part 9 or a claim made in accordance with regulations, it is shown to the satisfaction of the Revenue Commissioners that, as respects any taxable period, the amount of tax (if any) actually paid to the Collector-General in accordance with Chapter 3 of Part 9 together with the amount of tax (if any) which qualified for deduction under Chapter 1 of Part 8 exceeds the tax (if any) which would properly be payable if no deduction were made under Chapter 1 of Part 8, the Commissioners shall refund the amount of the excess less any sums previously refunded under this subsection or repaid under Chapter 1 of Part 8 and may include in the amount refunded any interest which has been paid under section 114.

(2) Where the Revenue Commissioners apply section 15 to a number of persons, the Commissioners may defer repayment of all or part of any tax refundable under subsection (1) to any one or more of those persons prior to the application of that section if any one or more of those persons have not furnished all returns and remitted all amounts of tax referred to in section 76 or 77, as may be appropriate, at the time of such application.

(3)(a) Subject to paragraph (b), the Revenue Commissioners may, where it appears requisite to them to do so for the protection of the revenue, require as a condition for making a refund in accordance with subsection (1) the giving of security of such amount and in such manner and form as they may determine.

(b) The amount of security referred to in paragraph (a) shall not, in any particular case, exceed the amount to be refunded.

(4) A claim for a refund under this Act may be made only within 4 years after the end of the taxable period to which it relates.

(5) Where the Revenue Commissioners refund any amount due under subsection (1) or section 100, they may, if they so determine, refund any such amount directly into an account, specified by the person to whom the amount is due, in a financial institution.

(6) The Revenue Commissioners shall not refund any amount of tax except as provided for in this Act or any order or regulations made under this Act.