(f) Special rules (1) Denial of double benefit Any deduction or credit otherwise allowed for the taxable year with respect to amounts described in subsection (e)(2)(A) shall be reduced by an amount equal to the qualified distributions attributable to such amounts. The adjusted basis of any property placed in service for the taxable year shall be reduced by the amount of any qualified distributions attributable to such property. For purposes of this paragraph, qualified distributions shall first be treated as attributable to amounts described in subsection (e)(2)(A), then to property placed in service for the taxable year. (2) Aggregation rule For purposes of this section, all persons treated as a single employer under subsection (a) or (b) of section 52, or subsection (m) or (o) of section 414, shall be treated as one person. . (b) Excise tax on excess contributions and nonqualified distributions Subtitle D of the Internal Revenue Code of 1986 is amended by adding at the end the following new chapter: 50A Small business start-up savings accounts Sec. 5000D. Tax on excess contributions to small business start-up savings accounts. Sec. 5000E. Tax on nonqualified distributions from small business start-up savings accounts. Sec. 5000F. Cross reference. 5000D. Tax on excess contributions to small business start-up savings accounts (a) In general In the case of a small business start-up savings account (within the meaning of section 7530) there is imposed for each taxable year a tax in an amount equal to 6 percent of the amount of the excess contributions to such taxpayer’s account (determined as of the close of the taxable year). (b) Limitation The amount of tax imposed by subsection (a) shall not exceed 6 percent of the value of the account (determined as of the close of the taxable year). (c) Excess contributions For purposes of this section, in the case of contributions to all small business start-up savings accounts maintained for the benefit of a person, the term excess contributions means the sum of— (1) the