| Constituo Software, LLC | Connecticut |
| Construction Management Solutions | Virginia |
| Construction Marketing, Inc. | |
| Construction Partner, Inc. | California |
| Construction Robotics | New York |
| Construction Systems Software, Inc. | Texas |
| ConstructionBevy | |
| Constructor | |
| Constructor.io | California |
| Construx | Washington |
| Construxi Design | |
| Consult PR | |
| ConsultCommerce | Colorado |
| ConsulTech Engineering, PLLC | New York |
| ConsultingWhiz, LLC | |
| Consultis | Florida |
| ConsultUSA | Pennsylvania |
| Consultwebs.com, Inc. | North Carolina |
| Consumer Buzz | |
| Consumer Cellular, Inc. | |
| Consumer Edge Holdings, LLC | |
| Consumer Fusion | California |
| Consumer Sleep Solutions, LLC | |
| Consumer Technology Association | Virginia |
| Consumer Technology Solutions, LLC | Texas |
| Consumer51, LLC | Pennsylvania |
| ConsumerSoft | New York |
| Contact Mapping | Colorado |
| Contact Solutions, LLC | Virginia |
| ContactDB | California |
| Contáctica | Puerto Rico |
| ContactMonkey, Inc. | |
| ContactOut | |
| Contata Solutions | Minnesota |
| Contec Systems | Pennsylvania |
| Contec Vision, Inc. | Massachusetts |
| Contegix | Missouri |
| Contego Medical, Inc. | North Carolina |
| Contegra Systems | New York |
| Contemporary Analysis | Nebraska |
| Contemporary Computer Services, Inc. | New York |
| Contemporary Control Systems, Inc. | Illinois |
| Contemporary Information Corporation | California |
| Contemporary Media Group, LLC | |
| Contemporary Systems | Washington |
| Contemporary Technologies, Inc. | Pennsylvania |
| Contensive | Virginia |
| Content Bureau | |
| Content Company | Illinois |
| Content Development Pros | |