40 ILCS 5/16-181
To keep sufficient cash on deposit in one or more banks, savings and loan associations or trust companies, organized under the laws of the State of Illinois or of the United States, for the purpose of making disbursements for annuities and other expenses; provided that the sum on deposit in any one bank, savings and loan association or trust company shall not exceed 25% of the paid up capital and surplus of the depository.
No bank or savings and loan association shall receive investment funds as permitted by this Section, unless it has complied with the requirements, other than the maximum deposit requirement, established pursuant to Section 6 of "An Act relating to certain investments of public funds by public agencies", approved July 23, 1943, as now or hereafter amended.
40 ILCS 5/16-181