- Southeast Industrial Equipment Inc.
- Southeast Iowa Regional Medical Center - Fort Madison
- Southeast Iowa Regional Medical Center - West Burlington
- Southeast Louisiana Area Health Education Center
- Southeast Louisiana Veterans Health Care System
- Southeast Rehab
- Southeastern Container, Inc.
- Southeastern Institute of Research, Inc.
- Southeastern Kidney Council- ESRA Network 6
- Southeastern Ohio Regional Medical Center
- Southeastern Regional Medical Center
- Southern Arizona VA Health Care System
- Southern Avionics Company
- Southern Building Systems, Inc.
- Southern California Hospital at Culver City
- Southern California Hospital at Hollywood
- Southern Company
- Southern Concrete Materials, Inc.
- Southern Connecticut State University
- Southern Eye Bank
- Southern Financial Bank - Horsepen Branch
- Southern Governors' Association
- Southern Hills Hospital and Medical Center
- Southern Historica Associan
- Southern Illinois Healthcare Foundation, Inc.
- Southern Illinois University
- Southern Illinois University School of Medicine
- Southern Iowa Oil
- Southern Maine Medical Center - Biddeford
- Southern Maine Medical Center - Sanford
- Southern Maryland Hospital Center
- Southern Medical Center
- Southern New Hampshire Medical Center
- Southern Ocean Medical Center
- Southern Ohio Medical Center
- Southern Regional Medical Center
- Southern Tennessee Regional Health System - Winchester
- Southern University and AandM College, School of Nursing
- Southern Utah University
- Southern Virginia Regional Med Center
- Southern Virginia Regional Medical Center
- Southern Wesleyan University
- Southhaven Chamber of Commerce
- Southside Community Hospital - Centra
- Southside Hospital
- Southside Regional Medical Center
- Southview Medical Center
- Southwell Medical
- Southwest Airlines
- Southwest Airlines