Mich. Comp. Laws § 208.1511

Sec. 511. Except as otherwise provided under section 500(7), a unitary business group shall file a combined return that includes each United States person, other than a foreign operating entity, that is included in the unitary business group. Each United States person included in a unitary business group or included in a combined return shall be treated as a single person and all transactions between those persons included in the unitary business group shall be eliminated from the business income tax base, modified gross receipts tax base, and the apportionment formula under this act. If a United States person included in a unitary business group or included in a combined return is subject to the tax under chapter 2A or 2B, any business income attributable to that person shall be eliminated from the business income tax base, any modified gross receipts attributable to that person shall be eliminated from the modified gross receipts tax base, and any sales attributable to that person shall be eliminated from the apportionment formula under this act.