Imposition of tax

Except as provided in subsection (e)— In the case of an individual, there is hereby imposed (in addition to any other tax imposed by this subtitle) for each taxable year a tax equal to 3.8 percent of the lesser of— the excess (if any) of— In the case of an estate or trust, there is hereby imposed (in addition to any other tax imposed by this subtitle) for each taxable year a tax of 3.8 percent of the lesser of— the excess (if any) of— For purposes of this chapter, the term “threshold amount” means— For purposes of this chapter— The term “net investment income” means the excess (if any) of— the sum of— A trade or business is described in this paragraph if such trade or business is— A rule similar to the rule of section 469(e)(1)(B) shall apply for purposes of this subsection. In the case of a disposition of an interest in a partnership or S corporation— The term “net investment income” shall not include any distribution from a plan or arrangement described in section 401(a), 403(a), 403(b), 408, 408A, or 457(b). Net investment income shall not include any item taken into account in determining self-employment income for such taxable year on which a tax is imposed by section 1401(b). For purposes of this chapter, the term “modified adjusted gross income” means adjusted gross income increased by the excess of— This section shall not apply to—