110 ILCS 992/15-10

No person, partnership, association, corporation, limited liability company, or other entity engaged in the business regulated by this Act shall operate such business under a name other than the real names of the entity and individuals conducting such business. Such business may in addition operate under an assumed corporate name pursuant to the Business Corporation Act of 1983, an assumed limited liability company name pursuant to the Limited Liability Company Act, or an assumed business name pursuant to the Assumed Business Name Act.