; and (C) 10 percent if the failure is for more than 15 days. (3) Funds The Secretary of the Treasury shall credit to the Fund, out of any sums in the Treasury not otherwise appropriated, the amount determined by the Executive Director to be necessary to carry out this section and section 105(d). 105. Contributions (a) Contributions by participants (1) In general Pursuant to the regulations established under paragraph (3) and subsection (e), a participant may make contributions to the participant’s account with the Fund in any pay period in an amount not to exceed the participant’s compensation for such period. (2) Other participant contributions (A) Catch-up contributions Notwithstanding the limitation under paragraph (1) or subsection (c), a participant may make such additional contributions to the participant’s account with the Fund as are permitted by section 414(v) of the Internal Revenue Code of 1986, and the regulations established under subsection (e) consistent therewith. (B) Contributions of tax refunds (i) In general Subject to the limits of subsection (c), a participant may elect, at such time and in such manner as the Secretary of the Treasury may prescribe, to contribute to the participant's account any portion of such participant's overpayment of tax which is to be refunded to such participant under section 6402 of the Internal Revenue Code of 1986. (ii) Special rules For purposes of clause (i)— (I) the amount of the overpayment which may be contributed under clause (i) shall be determined without regard to any overpayment attributable to the amount contributed to the account by the Secretary of the Treasury under section 25F of the Internal Revenue Code of 1986, and (II) any contribution described in clause (i) shall be treated as made for the taxable year of the overpayment and shall be taken into account in determining the amount of the credit under section 25F for such taxable year. (3) Contributions The Secretary of the Treasury and the Executive Director shall jointly prescribe regulations