740 ILCS 10/3
(1) Make any contract with, or engage in any combination or conspiracy with, any other person who is, or but for a prior agreement would be, a competitor of such person:
a. for the purpose or with the effect of fixing, controlling, or maintaining the price or rate charged for any commodity sold or bought by the parties thereto, or the fee charged or paid for any service performed or received by the parties thereto;
b. fixing, controlling, maintaining, limiting, or discontinuing the production, manufacture, mining, sale or supply of any commodity, or the sale or supply of any service, for the purpose or with the effect stated in paragraph a. of subsection (1);
c. allocating or dividing customers, territories, supplies, sales, or markets, functional or geographical, for any commodity or service; or
(from Ch. 38, par. 60-3)
(Source: P.A. 82-219.)