A registered entity shall comply with the following rules for purchasing allowances available at an auction:

(1) A covered entity or opt-in entity that is not a member of a direct corporate association shall not purchase more than 10 percent of the allowances available.

(2) A general market participant that is not a member of a direct corporate association shall not purchase more than four percent of the allowances available.

(3) For purposes of auction purchase limits, all members of a direct corporate association are considered to be a single party subject to the purchase limits in subsections (1) and (2) of this section. A covered entity or opt-in entity that is a member of a direct corporate association shall ensure that the purchase limit set out in subsection (1) of this section is allocated among the members of the direct corporate association.

(4) If the direct corporate association mentioned in subsection (3) of this section includes a general market participant, the allocation under subsection (3) of this section must be carried out in such a manner as to ensure the rule set out in subsection (5) of this section is also complied with.

(5) A general market participant that is a member of a direct corporate association shall ensure that the purchase limits set out in subsection (2) of this section are allocated among all members of the direct corporate association who are general market participants.

(6) No registered entity that is a member of a direct corporate association shall purchase more than the share of the purchase limit allocated to the registered entity under this section.