Mich. Comp. Laws § 440.1310: Subordination.

Sec. 1310.

An obligation may be issued as subordinated to performance of another obligation of the person obligated, or a creditor may subordinate its right to performance of an obligation by agreement with either the person obligated or another creditor of the person obligated. Subordination does not create a security interest as against either the common debtor or a subordinated creditor.