- C2 Solutions & Datacentrix, Ltd.
- Cadata Consulting, Ltd.
- Calamos Asset Management
- Calico Technology
- California Spine Institute
- Call Center Learning Solutions
- Call Interactive, Inc.
- Callipso Corp.
- Calypso Wireless, Inc.
- Cambridge Brass-Delta Faucet
- Cambridge Machinery
- Cambridge Technology Partners
- Cambridge Mercantile Corp.
- Camstar Systems, Inc.
- Canac
- Canberra
- Candle Corporation
- Capelle Associates, Inc.
- Cap Gemini Ernst & Young
- Capital Corp of the West County Bank
- The Capital Markets Company
- Capital Markets Compliance, LLC
- Capital Technologies, Inc.
- CapRock
- CAT Logistics
- Capstone Turbine Corp.
- Captura Software, Inc
- Carboloy, Inc.
- CardiacAssist, Inc.
- Cardinal Logistics Management
- Card Marte
- Cardio Ready
- Career Path Training Corporation
- Carefx Corporation
- Cares Built Inc.
- CarSch Management Services, Inc.
- The Carson Group
- Cash Recovery Specialtists
- Castrol Heavy Duty Lubricants
- Caterpillar Logistics
- Cayenta.com
- CBCL Limited Consulting Engineers
- CBF Group, Inc.
- CB Richard Ellis Services, Inc.
- C-bridge Internet Solutions, Inc.
- C-Chip Technologies Corporation
- Cedar
- Cegelec ESCA
- Cell-Loc Inc.
- Cellnet
- Cencorp
- Centaurian Systems, LLC
- Centaur Pharmaceuticals Inc.
- Center for Creative Leadership
- Centerstone Insurance & Financial Services
- Centrisys Corporation
- Centura Software Corp.
- Centurion Research Corp
- Century Corporation
- Century 21 Real Estate Corporation
- Cepex USA, Inc.
- Cergence, Inc.
- Ceridian
- CertCo, Inc.
- Certiport, Inc.
- Cetecom Inc.
- Ceto & Associates
- CGEY
- Champion Communications
- Champion Franchise Cleaners
- Champion International
- Champion Laboratories, Inc.
- Chancellor Corporation
- Chase Global Mutual Funds Corp.
- Cheetah Learning
- Chelsea Group
- ChemLogix, LLC
- CheMatch
- Cheque Guard
- Chiliad, Inc.
- Choice Logistics
- C. Hanse Instrumentation
- Chenega Federal Systems
- China Concept Consulting Ltd.
- Choice Pay
- ChooseEnergy.com
- Chryso, Inc.
- C&I Engeineering
- CIGNA Retirement & Investment Services
- CI labs
- Cimbix
- CIMCOR Inc.
- The CIMS Group
- Cincom
- Cinebase Software
- Circuit Breaker Sales
- Cisco Systems, Inc
- CISP
- CITEL Technologies
- Citizen 1 Software, Inc.
- City Networks
- Clarendon Photonics
- Clark MHC
- Clark Bardes Consulting
- Clean Burn
- Clean Energy, Inc.
- Clean Earth Technologies
- CleanWeb, Inc
- Clear Creek Systems
- CLEO Communications
- Clevrware, Inc.
- ClientSoft Inc.
- Clifton Steel Company
- Clyde Bergemann, Inc.
- CMI-HRSG
- CML Emergency Services
- CMS Manufacturing Systems
- Coach2100, Inc.
- Coastal Technologies Group
- coaXmedia
- Cobalt Networks, Inc.
- Coca Cola
- CodaOctopus Group, Inc.
- Code Blue Corp.
- Coface
- CoGentech Inc.
- Cogistics, Inc.
- The Coker Group
- Coleman Management Consultants
- Collaborative Consulting
- Collateral Risk Solutions
- Collegiate Development
- Columbia Ultimate
- Colomotion, Inc.
- Colorado Technical University
- Comarco Wireless Technologies
- Comau Pico
- Combined Logistics (USA), Inc
- Comdale Technologies
- COMDATA Corporation
- Comensura
- Commerce Route Inc.
- Commercial Defeasance
- Community ISP, Inc.
- Commodity Shop
- Como Industrial Equipment, Inc.
- Compass Staffing Solutions
- Compaq Computer Corp.
- Compaq's Enterprise Computing Group
- CompEraser, Inc.
- Complete Claim Solutions, Inc.
- Complete Parachute Solutions
- Compliance Automation
- ComplianceEase
- Composite Tek
- Comps.com, Inc.
- Computer Associates, Inc.
- Computer Generated Solutions, Inc
- Computer Information Analysts, Inc
- Computer Insights Inc.
- Computer Sciences Corporation
- Computer Sciences Corporation
- Computer Sciences Corporation
- Computer Sciences Corporation
- Computer Task Group
- Computerprep
- Comsearch
- Comshare Inc.
- Concert
- Concert Group Logistics (CGL)
- Concierge, Inc.
- Conco Systems, Inc.
- Condor Technical Solutions, Inc.
- ConectiSys, Corp.
- Configured Energy Systems
- Conforce International
- Conforma Clad
- Connectsoft Communications
- Conquest Innovations
- Consortium Service Management Group
- Consortium Outsourcing
- Consumer Direct of America
- Contemporary Realty Solutions
- Continuum Financial
- Continua Systems, Inc.
- Continuum Financial
- Conversational Computing
- Con-Way Transportation Services
- Consolidated Biofuels
- Consolidated Ecoprogress Technology, Inc.
- Cooley Inc.
- Copelco Capital Funding
- CoreExpress
- CorePROFIT
- Corniche Group, Inc.
- Cormax Business Solutions, Inc.
- Corporate One Federal Credit Union
- Corporate Systems, Inc.
- Corporate Vision, Inc.
- Corporate Visions, Inc.
- CorSolutions Medical, Inc.
- Corvis Corporation
- CoSine Communications
- Cosmobridge Alliance Group, Inc.
- Coss Technology Group
- Coudert Bros.
- CoverageCorp.Com
- CPP
- Creative Problem Solving Group
- The Credit Store, Inc.
- CreekPath Systems, Inc.
- Crème Dellatex
- Crestwood Technology Group
- Crimestar Corporation
- Crossmark
- Crossmark
- Crothall Services Group
- Crown Castle International
- Crown Castle International
- Crown Consulting, Inc.
- Crown Equipment Company
- CRS Press / Lewis
- Crushtek
- Cryovascular Systems, Inc.
- CryptCOM
- CryptoHeaven Development Team
- Crystallize Inc.
- Crys-Tel Telecommunications, Inc.
- CSCO, Ltd.
- CSCU
- CS Stars
- CSW Communications
- CTC Communications, Inc.
- CTC Engineering Consultants
- CTG
- CT Institute
- Cuadpro
- Cubic Corporation
- Cubicorp
- Cudd Pressure Control
- Cultec, Inc.
- Current Technologies, LLC
- Cushcraft Corporation
- Cuso Financial Services, L.P.
- Cultural Awareness
- CX2 Technologies
- CyberSentry, Inc.
- Cybersizzle
- CyberTech Systems, Inc.
- Cybrant Corporation
- Cyneta Networks
- CYGCOM Integrated Technologies
- Cygnifi Cypost Corporation