an expanded affiliated group has significant domestic business activities if at least 25 percent of— (A) the employees of the group are based in the United States, (B) the employee compensation incurred by the group is incurred with respect to employees based in the United States, (C) the assets of the group are located in the United States, or (D) the income of the group is derived in the United States, determined in the same manner as such determinations are made for purposes of determining substantial business activities under regulations referred to in paragraph (3) as in effect on January 18, 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. (6) Definitions and other rules (A) Expanded affiliated group The term expanded affiliated group has the meaning give such term under section 7874(c)(1). (B) Other rules Rules similar to the rules of paragraphs (2), (3), (5), and (6) of section 7874(c) shall apply for purposes of this subsection. .