70 ILCS 1205/8-8a

Any park district, when requested by its treasurer, may transfer the interest earned on any of the moneys of the district into the fund of the district that is most in need of the interest. This Section does not apply to any interest earned that has been earmarked or restricted for a designated purpose. This Section does not apply to any interest earned on any funds for the purposes of municipal retirement under the Illinois Pension Code and tort immunity under the Local Governmental and Governmental Employees Tort Immunity Act. Interest earned on these funds may be used only for the purposes authorized for the respective funds from which the interest earnings were derived.