| Clarity Cycle Consulting Limited | Professional & scientific | 2026 |
| Clarixos Ltd | Information & communication | 2025 |
| Clarkes Airport Transfers Limited | Transport & logistics | 2023 |
| Classic Racing Egts Ltd | Arts & recreation | 2014 |
| Clean Consultants Limited | Other services | 2014 |
| Clear Ovens Limited | Other services | 2010 |
| Clear View Accountancy Ltd | Professional & scientific | 2024 |
| Close Taxation & Accounting LLP | | 2017 |
| Cloud Nine Accounting Limited | Professional & scientific | 2020 |
| CLP Recruitment Ltd | Administrative & support | 2022 |
| Co Supply Station Limited | Wholesale & retail | 2017 |
| Cogels Consultancy Limited | Professional & scientific | 2020 |
| Coggeshall Town Football Club Limited | Arts & recreation | 2014 |
| Cognitial Limited | Professional & scientific | 2014 |
| Cohen & Bryan Interiors Ltd. | Manufacturing | 2014 |
| Coldstream Farming LLP | | 2023 |
| Colemans Roofing Ltd | Construction | 2023 |
| Colin Bowles Limited | Administrative & support | 1985 |
| Common Ground Events CIC | Hospitality | 2025 |
| Communitaccess CIC | Information & communication | 2023 |
| Compaccs Accountancy Services Limited | Professional & scientific | 2012 |
| Complete Tail Lift Solutions Ltd. | Manufacturing | 2017 |
| Complete Tail Lifts Limited | Manufacturing | 2019 |
| Compliant Secure Inventories Limited | Real estate | 2019 |
| Computer Generated Answers Limited | Real estate | 1989 |
| Computer Tuition Ltd | Information & communication | 2016 |
| Conductive Electrical Services Limited | Construction | 2024 |
| Connect Pilates Dunmow Ltd | Arts & recreation | 2024 |
| Connected Real Estate Ltd | Information & communication | 2007 |
| Connekd Ltd | Professional & scientific | 2026 |
| Construction Management Consultants Limited | Professional & scientific | 2011 |
| Contempo Glass Limited | Construction | 2016 |
| Continental Trade and Industry Limited | Wholesale & retail | 2017 |
| Cookngo Limited | Hospitality | 2017 |
| Corporate Presentations Direct Limited | Wholesale & retail | 2000 |
| Corringales Limited | Construction | 2016 |
| COS Civil Engineering Limited | Construction | 2021 |
| Cosmetic Facial (UK) Limited | Health & social care | 2012 |
| Cottons Farm Ltd | Construction | 2021 |
| Country View Landscapes Ltd | Administrative & support | 2020 |
| Courtlands Finance Limited | Financial services | 2025 |
| Courtney Park Engineering Limited | Real estate | 1987 |
| Cowdell Templating and Stonework Ltd | Construction | 2020 |
| Crackerjack Pet Products Ltd | Wholesale & retail | 2021 |
| Crafty Brewed Beverages Limited | Manufacturing | 2021 |
| CRB Consultants Ltd | Professional & scientific | 2006 |
| Credos Construction Ltd | Construction | 2018 |
| Crescendo Films Limited | Information & communication | 2015 |
| Crown & Anchor (Brixton) Limited | Hospitality | 2012 |
| Cruse Aesthetics Ltd | Health & social care | 2024 |
| CS Consultants (Essex) Ltd | Financial services | 2025 |
| CSC Telecoms Limited | Information & communication | 2021 |
| CT Estore Ltd | Information & communication | 2009 |
| Cubus Containers Ltd | Wholesale & retail | 2025 |
| CUL 50 Limited | Construction | 2013 |
| Cultr Gym Limited | Administrative & support | 2015 |
| Custom Trades Ltd. | Construction | 2024 |
| Cutlers Software Limited | Information & communication | 2024 |
| Cyprus Pitta Food Ltd | Hospitality | 2023 |
| D & D Homes Residential Limited | Real estate | 2018 |
| D & J Haigh Limited | Construction | 2010 |
| D & V Property UK Limited | Real estate | 2013 |
| D Lungo Construction Services Ltd | Construction | 2015 |
| D&J Driving Academy Limited | Education | 2002 |
| D&S Distribution Ltd | Transport & logistics | 2020 |
| Daly Brothers LLP | | 2010 |
| Damp Guardians Ltd | Construction | 2026 |
| Danly Cleaning Service Ltd | Administrative & support | 2025 |
| Darcelle Flooring Limited | Construction | 2016 |
| Darren Chung Photography Ltd | Professional & scientific | 2002 |
| Davenport Corporation Ltd | Real estate | 2020 |
| Dawn Louise Body Care Ltd | Other services | 2018 |
| Day Events Ltd | Hospitality | 2021 |
| Daybreak Services Limited | Transport & logistics | 2005 |
| DB Management Solutions Limited | Professional & scientific | 2024 |
| DC Design Interiors Limited | Construction | 2009 |
| DCA Financial Investments Ltd | Real estate | 2025 |
| Dcec Limited | Construction | 2013 |
| DE LA Terre Limited | Hospitality | 2025 |
| DE Sobra Limited | Information & communication | 2009 |
| DE Vere Construction Limited | Construction | 2011 |
| Dealt With Limited | Information & communication | 2021 |
| Dean Tatum Ltd | Wholesale & retail | 2012 |
| DECONFLICTION2025 Ltd | Professional & scientific | 2025 |
| Deepmist Limited | Administrative & support | 2004 |
| Deltagate Limited | Construction | 1992 |
| Demir Electrical Services Limited | Construction | 2021 |
| Dermabrand Aesthetics Ltd | Other services | 2023 |
| Derybrook Limited | Administrative & support | 2017 |
| Design and Build Developments Limited | Construction | 2014 |
| Design for Homes | Professional & scientific | 2000 |
| Design Verification Limited | Professional & scientific | 2023 |
| Desousa Property Ltd | Real estate | 2022 |
| DEU28 Ltd | Construction | 2020 |
| DGP Hairdressers Limited | Other services | 2001 |
| DH Agrisk Services Ltd | Financial services | 2015 |
| Digital Distance Ltd | Wholesale & retail | 2020 |
| Digital Inspector Ltd | Manufacturing | 2024 |
| Digital Systems Innovate Limited | Professional & scientific | 2016 |
| Digital Tech Consultancy Limited | Professional & scientific | 2021 |