- Sammons Preston Rolyan
- Sanyo Sales and Supply Co.
- Sarah Bush Lincoln Health System
- Sears Contract Sales
- Sears Holdings Co.
- Shawnee Health Service
- Shure Inc.
- Siemens Building Technologies
- SIU Medicine Springfield Residency Program
- Skidmore Owings and Merrill LLP
- Skokie Hospital
- Society of Actuaries
- Society of Critical Care Medicine
- Society of Permanent Cosmetic Professionals
- South Shore Hospital
- Southern Illinois Healthcare Foundation, Inc.
- Southern Illinois University
- Southern Illinois University School of Medicine
- Springfield Memorial Hospital
- St. Anthony Hospital
- St. Bernards Hospital
- St. Charles Business Alliance
- St. Xavier University
- Stanley Consultants, Inc. - Chicago
- State Farm Insurance Co.
- Streator Area United Way, Inc.
- Stroger Hospital
- Super 8 Motel, Calumet Park
- Swedish Hospital
- Taylorville Memorial Hospital
- Tazewell County
- Telusys Inc
- The Eureka Co.
- The Fancy Street Clock Co., LLC
- The Loretto Hospital
- The Society of Thoracic Surgeons
- Thrifty Inn, Mt. Vernon
- Tribune Company
- U.S. Department of Health and Human Services - HRSA
- U.S. Office of Personal Management Chicago Office
- UChicago AdventHealth Bolingbrook
- UChicago AdventHealth Hinsdale
- UChicago AdventHealth LaGrange
- UChicago AdventhHealth GlenOaks
- UI Health
- UNICUS Incorporated
- United Health Care of River Valley
- United Way of Adams County, Inc.
- United Way of Boone County
- United Way of Danville Area, Inc.