| Cocksedge Building Contractors Limited | Construction | 2000 |
| Coconut Media Limited | Wholesale & retail | 2026 |
| Coda Branding Ltd | Professional & scientific | 2013 |
| Code Red Security Solutions Limited | Construction | 2018 |
| Code Reload Limited | Information & communication | 2022 |
| Code Web Studio Ltd | Professional & scientific | 2025 |
| Codebody Ltd | Information & communication | 2023 |
| Codes Origin Ltd | Education | 2025 |
| Codexzel Ltd | Information & communication | 2025 |
| Coffee Cat Limited | Hospitality | 2016 |
| Coffee Cube Limited | Wholesale & retail | 2022 |
| Coffee House NO5 Limited | Hospitality | 2010 |
| Coffi Onnen Ltd | Hospitality | 2026 |
| Cogiro Ltd | Information & communication | 2011 |
| Cognesence Ltd | Information & communication | 2025 |
| Cognesta Ltd | Wholesale & retail | 2025 |
| Cognetheus Ltd | Administrative & support | 2025 |
| Cognis London Limited | Professional & scientific | 2026 |
| Cognita Learning LAB Ltd | Professional & scientific | 2025 |
| Cogu Culture Ltd | Financial services | 2025 |
| Colbear & Clark Ltd | Wholesale & retail | 2022 |
| Cold Front Ltd | Transport & logistics | 2024 |
| Cold Islanders CIC | Education | 2024 |
| Coldham Farm Limited | Agriculture & fishing | 2002 |
| Coldrey & Bryant Consultants Ltd | Financial services | 2002 |
| Cole Empire Limited | Professional & scientific | 2025 |
| Coledale Suffolk Limited | Real estate | 2021 |
| Colesco Ltd | Extraterritorial | 2020 |
| Collabgenics Limited | Financial services | 2026 |
| Collaborative Pharma Ltd | Professional & scientific | 2021 |
| Collaborative Solutions Group Ltd | Financial services | 2026 |
| Collect Monsters Ltd | Wholesale & retail | 2026 |
| College of Bowen Studies Ltd | Education | 2019 |
| Collekta Ltd | Wholesale & retail | 2024 |
| Coloforce Ltd | Information & communication | 2026 |
| Cologica Ltd | Professional & scientific | 2022 |
| Colorama Photodisplay Holdings Limited | Professional & scientific | 2002 |
| Colorgen Limited | Other services | 2002 |
| Colorwho Group Ltd | Wholesale & retail | 2025 |
| Colosseum Cards Ltd | Wholesale & retail | 2026 |
| Colourbox Montessori School Ltd | Education | 2010 |
| Colours Continental Cafe Limited | Hospitality | 2002 |
| Colt Customs Limited | Wholesale & retail | 2025 |
| Columbus Publishing Limited | Information & communication | 2010 |
| Columbus Ravine Ltd | Real estate | 2021 |
| Comacct Solutions Ltd | Information & communication | 2025 |
| Combatix Ltd | Other services | 2025 |
| Combine World Limited | Administrative & support | 1989 |
| Combined Heat Limited | Construction | 2012 |
| Combinez Ltd. | Information & communication | 2021 |
| Comet Power Ltd | Construction | 2023 |
| Comfort Homes From Home Ltd | Hospitality | 2025 |
| Comida Corriente Ltd | Hospitality | 2021 |
| Command Security Services and Facilities Management Ltd | Administrative & support | 2025 |
| Commerce Sail Limited | Wholesale & retail | 2025 |
| Commercial Energy Broker Ltd | Other services | 2023 |
| Commercial Trade Hub Ltd | Information & communication | 2025 |
| Commercial Utility Solutions Limited | Professional & scientific | 2017 |
| Common Cloud Ltd | Information & communication | 2022 |
| Common Orbit C.I.C. | Education | 2024 |
| Commonre Ltd | Information & communication | 2025 |
| Commonwealth Centre for Global Affairs Ltd | Education | 2025 |
| Commonwealth Investment Partners Limited | Administrative & support | 2018 |
| Communicarta Ltd. | Information & communication | 2004 |
| Community Interest Foundation CIC | Other services | 2023 |
| Community Workshop Limited | Health & social care | 2015 |
| Companion Consultancy Trustees Limited | Administrative & support | 2024 |
| Company 74 Limited | Real estate | 2021 |
| Company Services Provider Ltd | Information & communication | 2024 |
| COMPANY4YOU.CO.UK Ltd | Professional & scientific | 2021 |
| Compass Beauty Limited | Wholesale & retail | 2020 |
| Compass Point Manufacturing Recruitment Limited | Administrative & support | 2026 |
| Compass Point Recruitment (East Anglia) Limited | Professional & scientific | 2002 |
| Compassionate Steps Ltd | Health & social care | 2025 |
| COMPLET101 Ltd | Information & communication | 2025 |
| Complete Autos Ltd | Wholesale & retail | 2020 |
| Complete Diet Clinic Ltd | Health & social care | 2025 |
| Complete Entertainment Ltd | Arts & recreation | 2023 |
| Complete GP Training Limited | Education | 2023 |
| Completetek Ltd | Wholesale & retail | 2023 |
| Complex Ltd | Professional & scientific | 2025 |
| Compliancex Limited | Construction | 2024 |
| Complii Consultants Limited | Professional & scientific | 2022 |
| Composed Abodes Limited | Financial services | 2024 |
| Compubiz Ltd | Information & communication | 2009 |
| Computer Scene Ltd | Information & communication | 1992 |
| Computer Science Educators CIC | Education | 2025 |
| Computing Powers Ltd | Information & communication | 2023 |
| Concept Consulate Limited | Transport & logistics | 2025 |
| Concept&Graft Limited | Information & communication | 2010 |
| Concitatus Ltd | Information & communication | 2024 |
| Concorde Aviation Limited | Wholesale & retail | 2025 |
| Condor (SW) Limited | Transport & logistics | 2017 |
| Condor Catalyst Ltd | Real estate | 2022 |
| Conduit Asset Management Limited | Professional & scientific | 2005 |
| Confidant Management Services London Limited | Real estate | 2026 |
| Conflated Limited | Hospitality | 2024 |
| Connect BPM Ltd | Information & communication | 2012 |
| Connect Property Management Ltd | Real estate | 2024 |
| Connect Utilities Limited | Administrative & support | 2005 |