There is hereby imposed for each taxable year a tax in an amount equal to 5 percent of the amount of the excess contributions made by a person to or under a trust or trusts described in section 501(c)(21). The tax imposed by this subsection shall be paid by the person making the excess contribution.
26 U.S. Code § 4953. Tax on excess contributions to black lung benefit trusts
(a) Tax imposed
(b) Excess contributionFor purposes of this section, the term “excess contribution” means the sum of—
(2) the amount determined under this subsection for the preceding taxable year, reduced by the sum of—
(c) Treatment of withdrawal of excess contributionsAmounts distributed during the taxable year from a trust described in section 501(c)(21) to the contributor thereof the sum of which does not exceed the amount of the excess contribution made by the contributor shall not be treated as—
an act of self-dealing (within the meaning of section 4951),
a taxable expenditure (within the meaning of section 4952), or
an act contrary to the purposes for which the trust is exempt from taxation under section 501(a).