under regulations referred to in paragraph (3) as in effect on December 22, 2017, but applied by treating all references in such regulations to foreign country and relevant foreign country as references to the United States . The Secretary may issue regulations decreasing the threshold percent in any of the tests under such regulations for determining if business activities constitute significant domestic business activities for purposes of this paragraph. . (b) Conforming amendments (1) Clause (i) of section 7874(a)(2)(B) is amended by striking after March 4, 2003, and inserting after March 4, 2003, and before December 23, 2017, . (2) Subsection (c) of section 7874 is amended— (A) in paragraph (2)— (i) by striking subsection (a)(2)(B)(ii) and inserting subsections (a)(2)(B)(ii) and (b)(2)(B)(i)