40 ILCS 5/7-108: "Participating Instrumentality".

(a) A political entity created under the laws of the State of Illinois, without general continuous power to levy taxes, and which is legally separate and distinct from the State of Illinois and any municipality and whose employees by reason of their relation to such political entity are not employees of the State of Illinois or a municipality; for the purposes of providing annuities and benefits to its employees, the Police Officers' Pension Investment Fund, as created under Article 22B of this Code; and for the purposes of providing annuities and benefits to its employees, the Firefighters' Pension Investment Fund, as created under Article 22C of this Code.

(b) A not-for-profit organization, which is incorporated under the laws of the State of Illinois, or an association, membership in which is limited to municipalities or limited to townships and authorized by statute.