Mich. Comp. Laws § 38.1140d

Sec. 20d. (1) An investment fiduciary of a system having assets of less than $250,000,000.00 may invest not more than 15% of the system's assets in investments not otherwise qualified under this act, except as qualified in section 19a, whether the investments are similar or dissimilar to those specified in this act. (2) An investment fiduciary of a system having assets of $250,000,000.00 or more but less than $1,000,000,000.00 may invest not more than 20% of the system's assets in investments described in subsection (1). (3) An investment fiduciary of a system having assets of $1,000,000,000.00 or more may invest not more than 25% of the system's assets in investments described in subsection (1). (4) An investment fiduciary of a system who is the state treasurer may invest not more than 30% of the system's assets in investments described in subsection (1). (5) If an investment described in subsection (1) is subsequently determined to be permitted under another section of this act, then the investment shall no longer be included under this section. (6) This section shall not be used to exceed a percentage of total assets limitation for an investment provided in any other section of this act.