which is (during such ownership) a substantial contributor to the foundation, as defined in section 507(d)(2) and the regulations thereunder,
For purposes of section 4943, private foundation A is a disqualified person with respect to private foundation B, and private foundation B is a disqualified person with respect to private foundation A.
For purposes of paragraph (a)(1)(v) or this section, section 267(c) shall be applied without regard to section 267(c)(3), and stock constructively owned by an individual by reason of the application of section 267(c)(2) shall not be treated as owned by him if he is described in section 4946(a)(1)(D) but not also in section 4946(a)(1) (A), (B), or (C).
For purposes of paragraph (a)(1) (vi) and (vii) of this section, profits or beneficial interests constructively owned by an individual by reason of the application of section 267(c)(2) shall not be treated as owned by him if he is described in section 4946(a)(1)(D) but not in section 4946(a)(1)(A), (B) or (C).
Example. Partnership S is a substantial contributor to private foundation X. Trust T, of which G is sole beneficiary, owns 12 percent of the profits interest of S. G's husband, H, owns 10 percent of the profits interest of S. H is a disqualified person with respect to X (under section 4946(a)(1)(C)) because he is considered to own 22 percent of the profits interest of S (10 percent actual ownership, plus G's 12 percent constructively under section 267(c)(2)). G is a disqualified person with respect to X (under section 4946(a)(1)(C) because she is considered to own 22 percent of the profits interest of S (12 percent constructively by reason of her beneficial interest in trust T, plus 10 percent constructively under section 267(c)(2) by reason of being a member of the family of H).
With respect to any act or failure to act, any person described in subdivision (ii) of this subparagraph who has authority merely to recommend particular administrative or policy decisions, but not to implement them without approval of a superior, is not an officer. Moreover, such independent contractors as attorneys, accountants, and investment managers and advisers, acting in their capacities as such, are not officers within the meaning of subparagraph (1)(i) of this paragraph.
For example, a brother or sister of an individual is not a member of his family for purposes of this section. However, for example, the wife of a grandchild of an individual is a member of his family for such purposes. For purposes of this paragraph, a legally adopted child of an individual shall be treated as a child of such individual by blood.
26 C.F.R. §53.4946-1