70 ILCS 1515/6
Money received from the proceeds of taxes levied for the payment of principal of and interest upon such refunding and funding bonds shall be deposited in the depositary bank or savings and loan association of the Chicago Park District in a special account designated as "Chicago Park District and Superseded Park Districts Bond and Interest Sinking Fund Account." Said money shall be faithfully applied to the payment of the refunding and/or funding bonds and interest thereon for which such taxes were levied.
No bank or savings and loan association shall receive public funds as permitted by this Section, unless it has complied with the requirements 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.
If such money is not immediately necessary for the payment or redemption of refunding and/or funding bonds or if such bonds cannot be purchased before maturity, then said money may be invested under the direction of the commissioners in bonds or other interest bearing obligations of the United States and bonds of the State of Illinois.
The maturity date of the invested securities shall be prior to the due date of the refunding and/or funding bonds for the payment of which said money was collected. Such securities may be sold when ordered by the commissioners if necessary to obtain cash to meet bond and interest payments.
70 ILCS 1515/6