A deferred compensation agreement is an agreement between a company and an employee that withholds paying some of the employee's salary. The State of Illinois Deferred Compensation Plan is a supplemental retirement program for State employees.1. Deferred Compensation Agreement. The City of Chicago has approved an amended and restated City of Chicago Deferred Compensation Plan (the "Plan") effective January 1, 2002. These forms are also available in the DotLoop and DocuSign form libraries.