| The Construction Link, Inc. | New York |
| The Consultants Source, LLC | Illinois |
| The Consulting Source, Inc. | Colorado |
| The Consumer Engagement Company | Washington |
| The Convergence Group | Puerto Rico |
| The Conversion Mill | |
| The Copernican Group | California |
| The Copper Portico | |
| The Copy Cartel, LLC | |
| The Coterie.Me, Inc. | California |
| The Course Book | |
| The CoverPages | Massachusetts |
| The Cowork Lab, LLC | Texas |
| The Craneware Group | Georgia |
| The Creative Image | |
| The Creative Industry | |
| The Creative Momentum | |
| The Crown College | Tennessee |
| The Culver Group, LLC | Maryland |
| The Curating | |
| The Custom Websites | |
| The Cuttlefish, Inc. | |
| The CXO Fund | California |
| The Cyber Express | Georgia |
| The Cyber Fusion, Inc. | |
| The Cyber Image | Arizona |
| The Dallas Company, Inc. | Texas |
| The Data Administration Newsletter, LLC | California |
| The Data Bank, Inc. | Minnesota |
| The Data House | Ohio |
| The Data Pros | New Jersey |
| The Data Warehousing Institute | Washington |
| The Davisgroup, LLC | California |
| The DC Tree, LLC | |
| The Dealio Marketing | |
| The DEC Network | Texas |
| The December Marketing Group | New York |
| The Demex Group | District of Columbia |
| The Denali Group | Ohio |
| The Department of Marketing | |
| The Design Ape | |
| The Design Gym, LLC | |
| The Design Matic | |
| The Design People, Inc. | California |
| The Design Scratch | |
| The Design Spark | |
| The Designers Agency | |
| The Designs Empire | |
| The DesignSmith | Louisiana |
| The Dev Shop | |