- Security Title Company
- Security Title Guaranty
- Security Title Guaranty Company
- Security Unlimited
- Sedona Staffing Services
- See
- Seek Incorporated
- See's Candies
- See's Candies - Shops
- Sefcu
- Segal Company
- Seiko the Company Store
- SEKO Worldwide
- Select Auto
- Select Comfort
- Select Communications
- Select Mortgage
- Select Properties
- Select Staffing
- Selections Showroom-burn Supply
- Self Defense America
- Self Image
- Self Service Storage
- Self Storage
- Self Storage 1
- Self-Realization Fellowship
- Selix Formalwear
- Semcac Senior Dining
- Semco
- Sempra Energy Solutions
- Seneca Foods Corporation
- Seng Tire
- Senior Care
- Senior Citizens Club
- Senior Citizens Services
- Senior Community Services
- Senior Companion Program
- Senior Connection
- Senior Friends