The State of Illinois Deferred Compensation Plan is a supplemental retirement program for State employees. Download any State of Illinois Deferred Compensation Plan form now using Acrobat Reader.These forms allow data to be typed into the form and saved. You must sign and date the application. 1. Deferred Compensation Agreement. A deferred compensation agreement is an agreement between a company and an employee that withholds paying some of the employee's salary. Assessment Tax Deferral and Recovery Agreement, at the time you file this application. When a person receives wages (i.e.