Michigan Compiled Laws, Chapter 324. Natural Resources and Environmental Protection § 324.4507

Sec. 4507. Bonds issued under former Act No. 76 of the Public Acts of 1968 or this part are securities in which all banks, bankers, savings banks, trust companies, savings and loan associations, investment companies, and other persons carrying on a banking business; all insurance companies, insurance associations, and other persons carrying on an insurance business; and all administrators, executors, guardians, trustees, and other fiduciaries may properly and legally invest any funds, including capital, belonging to them or within their control.