Michigan Compiled Laws, Chapter 38. Civil Service and Retirement § 38.1140k

Sec. 20k. (1) Notwithstanding a percentage of total assets limitation for an investment provided in any other section of this act, an investment fiduciary who is the state treasurer or the investment fiduciary of a system that has assets of $2,000,000,000.00 or more may invest not more than 30% of a system's assets in global securities.An investment fiduciary of a system that has assets of less than $2,000,000,000.00 and who is not the state treasurer may invest not more than 20% of a system's assets in global securities. Except as otherwise provided in this act, an investment fiduciary shall not do any of the following:

(2) Investments in global securities under this section shall be made only by investment fiduciaries described in section 13(11)  1 who have demonstrated expertise in investments of that type.