Mich. Comp. Laws § 12.288
Notwithstanding any restriction contained in any other law, rule, regulation, or order to the contrary, this state and all political subdivisions of this state; their officers, boards, commissioners, departments or other agencies; governmental pension funds; all banks, trust companies, savings banks and institutions, building and loan associations, savings and loan associations, investment companies and other persons carrying on a banking or investment business; and all executors, administrators, guardians, trustees, and other fiduciaries; and all other persons whatsoever who now are or may hereafter be authorized to invest in bonds or other obligations of the state, may properly and legally invest any sinking funds, money, or other funds, including capital, belonging to them or within their control, in any bond. Bonds that the authority issues under this act are hereby made bonds that may properly and legally be deposited with, and received by, any state municipal officer or agency of this state, for any purpose for which the deposit of bonds or other obligations of this state is now, or may be, authorized by law.
MCL 12.288