| Cobalt Black Ltd | Professional & scientific | 2018 |
| Cobalt Health | Health & social care | 2002 |
| Cobalt Health Medical Limited | Health & social care | 2026 |
| Cobalt Unit Appeal Fund Ltd. | Health & social care | 2014 |
| Cobra Consultancy Ltd | Education | 2024 |
| Cocklebury Farmhouse Homes Limited | Health & social care | 2014 |
| Cockroach Labs UK Limited | Wholesale & retail | 2019 |
| Cocoa Hair Design (Hawkins) Limited | Other services | 2017 |
| Cocoon Blends Limited | Information & communication | 2022 |
| Codeite Ltd. | Information & communication | 2011 |
| Codel Consulting Ltd | Construction | 2018 |
| Codenham Lodge (Cheltenham) Limited | Households | 1977 |
| Codestone Limited | Information & communication | 1996 |
| Coffee and Bar Supplies Ltd | Administrative & support | 2018 |
| Cognit Solutions Limited | Information & communication | 2014 |
| Cognotiva Limited | Professional & scientific | 2012 |
| Cogo Agency Limited | Information & communication | 2010 |
| Cohesion Web Technologies Limited | Information & communication | 2016 |
| Coin Knowledge Limited | Information & communication | 2024 |
| Coin Metrics (U.K.) Limited | Information & communication | 2022 |
| Cojo Clothing Limited | Wholesale & retail | 2020 |
| Colborn Construction Limited | Construction | 2021 |
| Colbrans Solar ESS Limited | Energy | 2024 |
| Coldharbour (Blackwall) Management Limited | Real estate | 1988 |
| Coldspace Cold Rooms (UK) LLP | | 2015 |
| Coldspace Solutions Ltd | Construction | 2015 |
| Cole Accounting Limited | Professional & scientific | 2012 |
| Colebrook Properties Limited | Real estate | 2013 |
| Colehurst Park Limited | Real estate | 2000 |
| Colesbourne Gardens LLP | | 2003 |
| Colgate Farm Ltd | Agriculture & fishing | 2022 |
| Colin Bunce Limited | Health & social care | 2010 |
| Colin Rafferty Fine Art Limited | Wholesale & retail | 2014 |
| Colin Reid Glass Limited | Arts & recreation | 2010 |
| Collab Publishing Limited | Wholesale & retail | 2025 |
| COLLABOR8 Solutions Limited | Professional & scientific | 2018 |
| Collaborate Architectural Design Limited | Extraterritorial | 2022 |
| Collaborate Contracting Solutions Ltd | Professional & scientific | 2015 |
| Collaborative Construction Services Ltd | Real estate | 2012 |
| College Court (Swindon) Limited | Households | 1989 |
| Collett & Brooks Electrical Installations Limited | Construction | 2012 |
| Collingwood Property Services Ltd | Construction | 2014 |
| Colmans Farm Limited | Professional & scientific | 2018 |
| Colmore Gaskell Property Management Limited | Households | 2018 |
| Coln Clearances Limited | Households | 2001 |
| Coln Estates Limited | Real estate | 2021 |
| Coln Farming LLP | | 2012 |
| Coln Kitchen Ltd | Hospitality | 2020 |
| Coln Native Livestock Limited | Agriculture & fishing | 2025 |
| Coln Park Management Limited | Real estate | 2004 |
| Colne Saddlery Limited | Wholesale & retail | 2012 |
| Colnecombe Limited | Households | 1984 |
| Colossum Software Limited | Information & communication | 1984 |
| Colour Computers Limited | Information & communication | 1987 |
| Colourwheel Cheltenham Ltd | Education | 2018 |
| Colpeter Ltd | Wholesale & retail | 2024 |
| Coltham Fields Ltd | Real estate | 2023 |
| Columbia UK Holdings, Ltd. | Manufacturing | 2022 |
| Columbus Packaging Solutions Limited | Manufacturing | 2021 |
| Combesgate Consultancy Ltd | Professional & scientific | 2011 |
| Combined Defensive Arts Ltd | Education | 2020 |
| Comdronic Limited | Manufacturing | 2014 |
| Commercial Corporate Services Limited | Administrative & support | 2011 |
| Commercial Fleet Systems UK Limited | Wholesale & retail | 2008 |
| Commercial Foundations CIC | Manufacturing | 2015 |
| Commercial IT Services Ltd | Information & communication | 2011 |
| Commercial Limited | Administrative & support | 1991 |
| Commercially Public Ltd | Professional & scientific | 2016 |
| Committed Limited | Information & communication | 2016 |
| Committed Property Limited | Real estate | 2020 |
| Commonwealth Publishing Limited | Information & communication | 2026 |
| Commsaudit Limited | Professional & scientific | 1999 |
| Communicate Live Ltd | Administrative & support | 2003 |
| Communication Networking Systems Limited | Information & communication | 1995 |
| Communications Audit UK Limited | Manufacturing | 1985 |
| Communities Insurance Brokers Community Interest Company | Financial services | 2014 |
| Community Centre Social Club (Churchdown) Ltd | Hospitality | 2011 |
| Community Sports Foundation C.I.C. | Education | 2025 |
| Como Two Limited | Real estate | 2019 |
| Comodus Ltd | Construction | 2019 |
| Company 88 Ltd | Information & communication | 2018 |
| Company Finances Ltd | Financial services | 2008 |
| Company Liquidations Limited | Professional & scientific | 2012 |
| Company Vehicle Buyer Limited | Wholesale & retail | 2012 |
| Comparo Limited | Real estate | 1998 |
| Compass Holidays Ltd | Other services | 2007 |
| Complete Flue Solutions Limited | Construction | 2001 |
| Complete Pool Chemicals Limited | Administrative & support | 2010 |
| Complete Pool Controls Limited | Wholesale & retail | 2006 |
| Complete Project Development Limited | Construction | 2013 |
| Complete Utilities Limited | Administrative & support | 1998 |
| Composite Resources Ltd | Administrative & support | 2026 |
| Computing and Coding Limited | Information & communication | 2016 |
| Comstar Recruitment Ltd | Administrative & support | 2024 |
| Comzart Ltd | Wholesale & retail | 2020 |
| Concept 2 Launch (UK) Limited | Professional & scientific | 2017 |
| Concept IP Cheltenham Ltd | Professional & scientific | 2019 |
| Conceptual Spaces Limited | Real estate | 2019 |
| Conceptual Spaces Property Investments Ltd | Real estate | 2021 |
| Concierge-Europe.Com Ltd | Manufacturing | 2007 |