Example 1.

(a) The ABC partnership owns stock possessing 80 percent of the total combined voting power of all classes of stock entitled to voting of S corporation. ABC partnership is the common parent of a parent-subsidiary group of trades or businesses under common control consisting of the ABC partnership and S Corporation.

(b) Assume the same facts as in (a) and assume further that S owns 80 percent of the profits interest in the DEF Partnership. The ABC Partnership is the common parent of a parent-subsidiary group of trades or businesses under common control consisting of the ABC Partnership, S Corporation, and the DEF Partnership. The result would be the same if the ABC Partnership, rather than S, owned 80 percent of the profits interest in the DEF Partnership.

Example 2.

L Corporation owns 80 percent of the only class of stock of T Corporation, and T, in turn, owns 40 percent of the capital interest in the GHI Partnership. L also owns 80 percent of the only class of stock of N Corporation and N, in turn, owns 40 percent of the capital interest in the GHI Partnership. L is the common parent of a parent-subsidiary group of trades or businesses under common control consisting of L Corporation, T Corporation, N Corporation, and the GHI Partnership.

Example 3.

ABC Partnership owns 75 percent of the only class of stock of X and Y Corporations; X owns all the remaining stock of Y, and Y owns all the remaining stock of X. Since interorganization ownership is excluded (that is, treated as not outstanding) for purposes of determining whether ABC owns a controlling interest of at least one of the other organizations, ABC is treated as the owner of stock possessing 100 percent of the voting power and value of all classes of stock of X and of Y for purposes of paragraph (b)(1)(ii) of this section. Therefore, ABC is the common parent of a parent-subsidiary group of trades or businesses under common control consisting of the ABC Partnership, X Corporation, and Y Corporation.

Example 4.

Unrelated individuals A, B, C, D, E, and F own an interest in sole proprietorship A, a capital interest in the GHI Partnership, and stock of corporations M, W, X, Y, and Z (each of which has only one class of stock outstanding) in the following proportions:

Organizations

Individuals	A	GHI	M	W	X	Y	Z
A	100%	50%	100%	60%	40%	20%	60%
B	—	40%	—	15%	40%	50%	30%
C	—	—	—	—	10%	10%	10%
D	—	—	—	25%	—	20%	—
E	—	10%	—	—	10%	—	—
	100%	100%	100%	100%	100%	100%	100%

Under these facts the following four brother-sister groups of trades or businesses under common control exist: GHI, X and Z; X, Y and Z; W and Y; A and M. In the case of GHI, X, and Z, for example, A and B together have effective control of each organization because their combined identical ownership of GHI, X and Z is greater than 50%. (A's identical ownership of GHI, X and Z is 40% because A owns at least a 40% interest in each organization. B's identical ownership of GHI, X and Z is 30% because B owns at least a 30% interest in each organization.) A and B (the persons whose ownership is considered for purposes of the effective control requirement) together own a controlling interest in each organization because they own at least 80% of the capital interest of partnership GHI and at least 80% of the total combined voting power of corporations X and Z. Therefore, GHI, X and Z comprise a brother-sister group of trades or businesses under common control. Y is not a member of this group because neither the effective control requirement nor the 80% controlling interest requirement are met. (The effective control requirement is not met because A's and B's combined identical ownership in GHI, X, Y and Z (20% for A and 30% for B) does not exceed 50%. The 80% controlling interest test is not met because A and B together only own 70% of the total combined voting power of the stock of Y.) A and M are not members of this group because B owns no interest in either organization and A's ownership of GHI, X and Z, considered alone, is less than 80%.

Example 5.

The outstanding stock of corporations U and V, which have only one class of stock outstanding, is owned by the following unrelated individuals:

Corporations

Individuals	U	(percent)	V	(percent)
A	12	12
B	12	12
C	12	12
D	12	12
E	13	13
F	13	13
G	13	13
H	13	13
	100	100

Any group of five of the shareholders will own more than 50 percent of the stock in each corporation, in identical holdings. However, U and V are not members of a brother-sister group of trades or businesses under common control because at least 80 percent of the stock of each corporation is not owned by the same five or fewer persons.

Example 6.

A, an individual, owns a controlling interest in ABC Partnership and DEF Partnership. ABC, in turn, owns a controlling interest in X Corporation. Since ABC, DEF, and X are each members of either a parent-subsidiary group or a brother-sister group of trades or businesses under common control, and ABC is the common parent of a parent-subsidiary group of trades or businesses under common control consisting of ABC and X, and also a member of a brother-sister group of trades or businesses under common control consisting of ABC and DEF, ABC Partnership, DEF Partnership, and X Corporation are members of the same combined group of trades or businesses under common control.