The Illinois Order of Consolidation Within Division is a tool used by the Illinois Department of Revenue (IDOL) to simplify tax filing when companies have multiple business entities in the same state. It allows businesses to file one single return for the entire group of companies, rather than filing separate returns for each entity. This process eliminates the need for multiple returns and simplifies the filing process. There are three types of Illinois Order of Consolidation Within Division: Regular Consolidation, Simplified Consolidation, and Combined Reporting Consolidation. Regular Consolidation allows the company to combine multiple entities under the same employer identification number (EIN) and file one return. Simplified Consolidation allows companies to combine multiple entities but file separate returns for each. Combined Reporting Consolidation allows companies to combine multiple entities under one EIN, but file separate returns for certain taxes such as sales and use tax.