| Communications Depot | Florida |
| Communications Electronics, Inc. | Maryland |
| Communications Engineering Company | Iowa |
| Communications Express | Virginia |
| Communications Industry Researchers | Virginia |
| Communications NW | Oregon |
| Communications Products, Inc. | Indiana |
| Communications Resource, LLC | Mississippi |
| Communications Software Consultants | New York |
| Communications Supply Service Association | Arkansas |
| Communications Systems, Inc. | Minnesota |
| CommunicationWorks, LLC | District of Columbia |
| Communico | Connecticut |
| Communicopia Marketing Services, Inc. | |
| Communicorp | Georgia |
| CommuniGate Systems, Inc. | California |
| Communikeyz | |
| Communiqué Conferencing, Inc. | Virginia |
| Community | |
| Community Brands Intermediate, LLC | |
| Community Communications, Inc. | Massachusetts |
| Community CoWorks | Wisconsin |
| Community ISP, Inc. | Ohio |
| Community IT Innovators, Inc. | District of Columbia |
| Community Phone | |
| Community Telephone Company, Inc. | Texas |
| Community Web Development, Inc. | |
| CommunityEngine | Minnesota |
| CommunityPass | |
| CommunityWFM | Texas |
| CommunityWide | |
| Commure, Inc. | |
| CommUSA, Inc. | California |
| Commusoft, Inc. | |
| Commutative Algebra Community | California |
| Commutyble | District of Columbia |
| Commvault | New Jersey |
| ComNet Communications, LLC | Connecticut |
| Comnet Consulting, Inc. | New Mexico |
| Comnexia Corporation | Georgia |
| Comnez, Inc. | Iowa |
| Comnio | |
| COMO Marketing | |
| Comodo Security Solutions, Inc. | New Jersey |
| Comos | California |
| Comosoft, Inc. | Texas |
| Comp&Soft, Inc. | Missouri |
| Comp-U-Floor | Florida |
| Compact Power Co. | California |
| CompAndSave.Com, Inc. | California |