| Communergy Ltd | Wholesale & retail | 2023 |
| Company-X Cyber Risk Limited | Information & communication | 2023 |
| Company-X Cyber Risk Nominees Limited | Professional & scientific | 2023 |
| Compassion UK Christian Child Development | Other services | 1999 |
| Complete Care@Home Limited | Health & social care | 2017 |
| Complete Yacht Solutions Ltd | Other services | 2010 |
| Compliance Consulting Associates Limited | Professional & scientific | 2009 |
| Compsoft Limited | Information & communication | 1990 |
| Computational Software Limited | Information & communication | 1986 |
| Computer Qwerks Ltd | Information & communication | 2011 |
| Concept Bingo Limited | Administrative & support | 2014 |
| Concrete Limited | Construction | 2018 |
| Congitech Limited | Information & communication | 2025 |
| Consulting SV Limited | Construction | 2023 |
| Contentaz Limited | Professional & scientific | 2025 |
| Contentengineer Limited | Information & communication | 2001 |
| Contractor Stop Ltd | Hospitality | 2025 |
| Control Entertainment Development Limited | Information & communication | 2018 |
| Control Entertainment HHB Limited | Information & communication | 2017 |
| Control Entertainment Productions Limited | Administrative & support | 2015 |
| Cool Music Group Ltd | Arts & recreation | 2026 |
| Coolbag Limited | Professional & scientific | 2015 |
| Coopergate Clinical Solutions Ltd | Public administration | 2026 |
| Coopernova Ltd | Information & communication | 2025 |
| Copper Craft Ltd | Construction | 2018 |
| Copydyne Communications Limited | Manufacturing | 2011 |
| Cornwall and Isles of Scilly Investment LP | | 2018 |
| Corvon Group Ltd | Information & communication | 2026 |
| Corvonix Ltd | Information & communication | 2026 |
| Cosmos Consultancy Limited | Professional & scientific | 2021 |
| Costello Software Ltd | Information & communication | 2010 |
| Cottony Ltd | Information & communication | 2010 |
| Coxheath Consulting Ltd | Professional & scientific | 2026 |
| Cozy Casa Holdings Ltd | Professional & scientific | 2023 |
| CP & I Limited | Information & communication | 1991 |
| Cpca Business Growth Finance Limited | Financial services | 2023 |
| CPD Digital Learning Limited | Education | 2019 |
| Cpeel Holdings Ltd | Financial services | 2025 |
| CQ Windows Limited | Manufacturing | 2022 |
| Cranbrook Cottages Freehold Limited | Households | 2021 |
| Crane Homes Ltd | Real estate | 2023 |
| Cranford Design Limited | Professional & scientific | 2012 |
| Cranford Mortgage Services Limited | Financial services | 2023 |
| Cranford Motor Co Ltd | Wholesale & retail | 2018 |
| Crawley Porterhouse Management Ltd | Households | 2005 |
| Crazy Customs Ltd | Manufacturing | 2024 |
| Crazy Gecko Limited | Professional & scientific | 2013 |
| Create- I Limited | Administrative & support | 2010 |
| Creative Gravy Ltd | Administrative & support | 2010 |
| Creativesoft Ltd | Information & communication | 2025 |
| Credfeld Group Ltd | Administrative & support | 2017 |
| Crescendoonline Limited | Information & communication | 2022 |
| Cristal Windows Doors & Conservatories Limited | Construction | 2006 |
| Critica Solutions Ltd | Information & communication | 2020 |
| CRK Accounting Ltd | Professional & scientific | 2013 |
| Crookham Car-Wash Limited | Administrative & support | 2023 |
| Crookham Engineering Ltd | Professional & scientific | 2018 |
| Crookham Hacklab CIC | Education | 2022 |
| Crookham Street Consulting Ltd | Administrative & support | 2013 |
| Crownwood Electrical Limited | Construction | 2006 |
| Crowthorne Group Limited | Professional & scientific | 2004 |
| Crowthorne Hi-Tec Services Limited | Construction | 1986 |
| Crowthorne Limited | Construction | 1992 |
| CS Cloud Ltd | Information & communication | 2020 |
| CS PM Consultancy Limited | Construction | 2022 |
| Csdradconsultancy Limited | Administrative & support | 2013 |
| Csight Marketing Consultancy Ltd | Professional & scientific | 2019 |
| Csluxurysourced Ltd | Wholesale & retail | 2023 |
| CTK Limited | Information & communication | 2018 |
| Cucumber Technology Ltd | Information & communication | 2015 |
| Cult of Customs Ltd | Extraterritorial | 2025 |
| Curious Explorers Ltd | Education | 2015 |
| Curtiss House (Farnborough) Residents Management Company Limited | Households | 2015 |
| Customer First Marketing Limited | Professional & scientific | 2018 |
| Cutts Electrical Ltd | Construction | 2012 |
| Cv-Library Holdings Limited | Administrative & support | 2013 |
| Cv-Library Ltd | Information & communication | 2003 |
| Cyber Actus Solutions Limited | Administrative & support | 2024 |
| Cyber Efficiency Solutions Ltd | Information & communication | 2016 |
| Cybermix Ltd | Information & communication | 2020 |
| Cygnet Court Residents Association Limited | Households | 1993 |
| D a J Consulting Limited | Other services | 2013 |
| D J Estates Limited | Construction | 2006 |
| D S Baker IT Ltd | Information & communication | 2006 |
| D&G Business Services Limited | Administrative & support | 2025 |
| D. L. Welsh Decorators Limited | Other services | 2002 |
| D.W. Smith Services Ltd | Construction | 2009 |
| D3ZENITH Services Limited | Professional & scientific | 2024 |
| Daden Interiors Limited | Wholesale & retail | 2004 |
| Daisychains Crochet Ltd | Manufacturing | 2025 |
| Damen Limited | Information & communication | 1996 |
| Damion Berridge Golf Studio Ltd | Construction | 2019 |
| Dancety Ltd | Wholesale & retail | 2021 |
| Danehurst MGY Limited | Construction | 2018 |
| Daniel Welch Automotive Limited | Wholesale & retail | 2026 |
| Daning Inc Ltd | Professional & scientific | 2020 |
| Dart Frog Gaming Limited | Information & communication | 2019 |
| Database Experts Limited | Information & communication | 2011 |
| Dataclear Ltd | Information & communication | 2011 |
| Dataplexus Ltd | Administrative & support | 2003 |