in which such eligible insourcing expenses were paid or incurred. For purposes of this subsection, full-time equivalent employees has the meaning given such term under section 45R(d) (and the applicable rules of section 45R(e)), determined by only taking into account wages (as otherwise defined in section 45R(e)) paid with respect to services performed within the United States. All employers treated as a single employer under subsection (b), (c), (m), or (o) of section 414 shall be treated as a single employer for purposes of this subsection. (d) Credit allowed upon completion of insourcing plan (1) In general Except as provided in paragraph (2), eligible insourcing expenses shall be taken into account under subsection (a) in the taxable year during which the plan described in subsection (b)(5) has been completed and all eligible insourcing expenses pursuant to such plan have been paid or incurred. (2) Election to apply employment test and claim credit in first full taxable year after completion of plan If the taxpayer elects the application of this paragraph, eligible insourcing expenses shall be taken into account under subsection (a) in the first taxable year after the taxable year described in paragraph (1). (e) Possessions treated as part of the United States For purposes of this section, the term United States shall be treated as including each possession of the United States (including the Commonwealth of Puerto Rico and the Commonwealth of the Northern Mariana Islands). (f) Regulations The Secretary shall prescribe such regulations or other guidance as may be necessary or appropriate to carry out the purposes of this section. . (b) Credit To Be Part of General Business Credit Section 38(b) of such Code is amended by striking plus at the end of paragraph (32), by striking the period at the end of paragraph (33) and inserting , plus , and by adding at the end the following new paragraph: (34) the insourcing expenses credit determined under section 45U(a). . (c) Conforming amendments (1) Section 280C of