| Care Link Recruitment Ltd | Administrative & support | 2025 |
| Carlton House Holdings Limited | Other services | 2019 |
| Carpediem Angling Limited | Agriculture & fishing | 2002 |
| Carthy's Construction Limited | Construction | 2012 |
| Carthy's Plumbing & Heating Services Limited | Construction | 2011 |
| Casa Cacti Ltd | Information & communication | 2025 |
| Cavendish Medical Search Limited | Administrative & support | 2026 |
| Cellpak PLC | Financial services | 2013 |
| Cette Services Ltd | Professional & scientific | 2014 |
| CGJ Property Ltd | Real estate | 2021 |
| CGP Stores Limited | Wholesale & retail | 2022 |
| Challenging Frontiers Ltd | Professional & scientific | 2012 |
| Chandlers Homecare Limited | Health & social care | 2019 |
| Change Ahead Consulting Limited | Professional & scientific | 2023 |
| Charnwood Forest Turf Accountants Limited | Professional & scientific | 1964 |
| Check View Ltd | Real estate | 2016 |
| Chelmer Court Management Co (London) Limited | Households | 1992 |
| Chelsea Natural Health Clinic Ltd | Other services | 2005 |
| Cherry Salad Ltd | Information & communication | 2008 |
| Chetplan Properties Limited | Real estate | 1982 |
| Chic Balayage Hair Salon Limited | Other services | 2025 |
| Chigwell Meadows Limited | Arts & recreation | 2012 |
| Chigwell Tree Services Ltd | Agriculture & fishing | 2024 |
| Chris Neill Productions Limited | Arts & recreation | 2012 |
| Chris Ring Consulting Limited | Information & communication | 1998 |
| Christian Enterprises Ltd | Information & communication | 2025 |
| Christopher Davis Homes Limited | Real estate | 2012 |
| Chuckie Holdings Limited | Real estate | 2017 |
| Church for the City (East London) | Other services | 2001 |
| Churchfields Care Home Limited | Health & social care | 2015 |
| CIA London Limited | Construction | 2013 |
| Cihangir Property Limited | Real estate | 2019 |
| Cimac Limited | Administrative & support | 2013 |
| Cinema Rooms Ltd | Wholesale & retail | 2009 |
| Circle Automotive Ltd | Other services | 2014 |
| City Glow Tanning Limited | Other services | 2025 |
| City of London Tours Ltd | Administrative & support | 2025 |
| Citysys Limited | Real estate | 2010 |
| CJA Media Group Ltd | Information & communication | 2025 |
| CJS Collective Ltd | Wholesale & retail | 2026 |
| CK Entertainments Ltd | Hospitality | 2019 |
| CK Home Furniture Limited | Wholesale & retail | 2022 |
| CK Upholstery Ltd | Manufacturing | 2021 |
| CL Grisha Ltd | Construction | 2019 |
| Clark Racing (Northern) Limited | Arts & recreation | 1990 |
| Clarke Group Finance Limited | Other services | 2019 |
| Clarke Group International Limited | Wholesale & retail | 2018 |
| Clarke International Limited | Wholesale & retail | 1970 |
| Clarke Property Holdings Limited | Construction | 2016 |
| Clarke Universal Limited | Professional & scientific | 1984 |
| Clarkes Compressors Limited | Professional & scientific | 1970 |
| Clasper Property Services Limited | Transport & logistics | 1993 |
| Clavis Locksmiths Limited | Other services | 2025 |
| Clear Coat and Clear OUT Ltd | Construction | 2025 |
| Clear IT. Ltd | Transport & logistics | 2024 |
| Clearview Units Limited | Construction | 2023 |
| Close Distances Ltd | Information & communication | 2026 |
| Club AC30 LLP | | 2009 |
| Clumber Consulting Limited | Professional & scientific | 2007 |
| CMC Motors Limited | Wholesale & retail | 2010 |
| CMD Residential Ltd | Construction | 2018 |
| CNV Trading Limited | Professional & scientific | 2016 |
| Cobbin Floyd Ltd | Professional & scientific | 2010 |
| Cocktail Toppers Pro Ltd | Wholesale & retail | 2023 |
| Coco Flooring Limited | Wholesale & retail | 2022 |
| Codextra Ltd | Wholesale & retail | 2023 |
| Cognify IQ Limited | Information & communication | 2017 |
| COLAB13 Creative Ltd | Professional & scientific | 2024 |
| Columbus Ltd | Extraterritorial | 2008 |
| Columbus Property Investments Limited | Real estate | 1994 |
| Colve Communications Ltd | Professional & scientific | 2025 |
| Commodum Invest Limited | Real estate | 2022 |
| Community of Hashem Worldwide | Other services | 2024 |
| Company Consultancy Limited | Professional & scientific | 2025 |
| Comply Consult Limited | Professional & scientific | 2024 |
| Conduit Street Holdings Limited | Real estate | 1991 |
| Construct Estate Ltd | Construction | 2022 |
| Contains Real Humans Ltd | Professional & scientific | 2026 |
| Contract Vision (FM) Limited | Professional & scientific | 2004 |
| Contractbuddy Ltd | Information & communication | 2025 |
| Convit House Pathology Ltd. | Health & social care | 2016 |
| Copped Hall (Epping) Management Ltd | Households | 1996 |
| Coppedhall Ltd | Households | 2022 |
| Copper Properties & Homes Ltd | Real estate | 2021 |
| Coppice Farm South Limited | Construction | 2020 |
| Coresynergy FM Ltd | Construction | 2026 |
| Cornwall Garden Rooms Ltd | Extraterritorial | 2026 |
| Courier Link Ltd | Transport & logistics | 2022 |
| Courteville Limited | Information & communication | 2020 |
| Coward Popplewells (Holdings) Limited | Professional & scientific | 2010 |
| Coward Popplewells Limited | Real estate | 1998 |
| CPW Global Consulting Limited | Professional & scientific | 2020 |
| CPW HR Consulting Limited | Professional & scientific | 2018 |
| Crawley Refurbishments Ltd | Construction | 2022 |
| Crayward Residential Ltd | Real estate | 2022 |
| CRE8 Design & Decor Limited | Construction | 2023 |
| CRE8 Sign Supplies Ltd | Construction | 2024 |
| Create Buildings LLP | | 2019 |
| Creeds Farm Yard Limited | Administrative & support | 2010 |
| Crete Products Ltd | Manufacturing | 2024 |