| Conyers Ventures Limited | Professional & scientific | 2023 |
| Cook & Associates Lift Consultants Limited | Professional & scientific | 2006 |
| Cook & Associates M & E Consultants Limited | Extraterritorial | 2007 |
| Cookie and Bear Luxury Trading Ltd | Wholesale & retail | 2021 |
| Cool and Bespoke Limited | Manufacturing | 2015 |
| Cool HI UK Ltd | Wholesale & retail | 2019 |
| Cool London Rental Services Ltd | Other services | 2015 |
| Coolbox Films Limited | Information & communication | 2017 |
| Coombe House Properties Limited | Construction | 2014 |
| Coopcrest Limited | Other services | 1979 |
| Cooper Wood & Associates LLP | | 2020 |
| Copelands (Beckenham) Limited | Extraterritorial | 2008 |
| Copers Cope Road Management Company Limited | Households | 1998 |
| Copper Bar London Ltd | Hospitality | 2019 |
| Copper Works Apartments RTM Company Limited | Households | 2025 |
| Coppice Close Ltd | Construction | 2023 |
| Copthorne Builders Limited | Construction | 2017 |
| Copthorne Developments Leases Limited | Real estate | 2021 |
| Copthorne Developments Limited | Construction | 2014 |
| Copthorne Properties Limited | Construction | 2017 |
| Copy, Print, TAB Ltd. | Administrative & support | 1997 |
| COR Bakes Ltd | Education | 2026 |
| Core Counselling Academy Ltd | Education | 2022 |
| Core Invest Ltd | Real estate | 2026 |
| Core Reformer Ltd | Health & social care | 2024 |
| Corfu Plus Ltd Limited | Financial services | 2025 |
| Corkncask Events Ltd | Hospitality | 2023 |
| Corkncask Ltd | Hospitality | 2022 |
| Corkscrew Properties Ltd | Construction | 2021 |
| Corner House Residents Management Company Limited | Households | 2004 |
| Cornerstone Couriers Limited | Transport & logistics | 2021 |
| Cornerstone Energy Limited | Professional & scientific | 2025 |
| Cornerstone Lifestyle Ltd | Administrative & support | 2026 |
| Cornerstone Management Group Ltd | Households | 2025 |
| Cornerstone North Sea Ltd | Mining & quarrying | 2020 |
| Cornerstone OIL and GAS (US) Limited | Professional & scientific | 2020 |
| Cornerstone Pre-Construction Ltd | Construction | 2026 |
| Cornhill Developments Limited | | 1971 |
| Corona Technologies Limited | Manufacturing | 1998 |
| Corporate LET London Limited | Real estate | 2014 |
| Corporation Sell Limited | Information & communication | 2020 |
| Correlia Limited | Information & communication | 2013 |
| Corrine Creates Ltd | Extraterritorial | 2022 |
| Cortex Global Advisory Ltd | Professional & scientific | 2025 |
| Cosbro LLP | | 2014 |
| Cosmic Cart Ltd | Wholesale & retail | 2023 |
| Cosmos Trading Co. Ltd | Wholesale & retail | 2024 |
| Cosy and Cool Plumbing Ltd | Construction | 2026 |
| Cotswold Craft Ltd | Manufacturing | 2019 |
| Cotswold Craft Property Ltd | Real estate | 2026 |
| Cotswolds Discovery Tours Limited | Administrative & support | 2023 |
| Cottage Avenue Residents Company Limited | Households | 1969 |
| Cotterell Limited | Professional & scientific | 2009 |
| Cotton Lane RTM Company Ltd | Households | 2022 |
| Counciil Estates Limited | Administrative & support | 2022 |
| Coup Technology Limited | Information & communication | 2014 |
| Course to Steer Limited | Professional & scientific | 2011 |
| Court Hotel (Bromley) Limited(The) | Hospitality | 1931 |
| Courtney Erin Limited | Other services | 2012 |
| Cove Business Centre Management Limited | Real estate | 2026 |
| COX Mountain Limited | Wholesale & retail | 2021 |
| Cox's Glass & Glazing Limited | Construction | 2021 |
| Coxheath Care Home Ltd | Health & social care | 2025 |
| Cozmoca Ltd | Other services | 2024 |
| CPA & I Limited | Professional & scientific | 2017 |
| Cpbl Ltd | Construction | 2019 |
| CPG Property Ltd | Real estate | 2022 |
| CPL Specialist Talent Limited | Administrative & support | 2018 |
| CR Estate Management Limited | Households | 2024 |
| Crafted Content Creation Limited | Administrative & support | 2024 |
| Crafted Interiors Ltd | Construction | 2018 |
| Craigmore Tower Limited | Households | 2004 |
| Crane & Partners Audit LLP | | 2025 |
| Cranfield Carpets Limited | | 1960 |
| Cranford Mews Residents Association Limited | Households | 2007 |
| Cranium Consulting Limited | Information & communication | 2010 |
| Craven Bespoke Carpentry Ltd | Construction | 2025 |
| Crea Marine Limited | Extraterritorial | 2026 |
| Creams Romford Ltd | Hospitality | 2026 |
| Creams Walsall Limited | Hospitality | 2025 |
| Creamtrans Limited | Transport & logistics | 2019 |
| Create Live Limited | Administrative & support | 2002 |
| Creative Designs II Ltd | Professional & scientific | 2022 |
| Creative Operations Ltd | Professional & scientific | 2024 |
| Creative Sailing Ltd | Construction | 2023 |
| Credence Business Consultants Ltd | Administrative & support | 2022 |
| Crep Guardiola Ltd | Wholesale & retail | 2021 |
| Creyf's Recruitment (Warrington) Limited | Administrative & support | 2001 |
| Creyf's Security Services Limited | Administrative & support | 2006 |
| CRG Holdco Limited | Mining & quarrying | 2020 |
| Crisdental Limited | Health & social care | 2019 |
| Cristiana Comfort Care (UK) Limited | Health & social care | 2013 |
| Crit Damage Limited | Information & communication | 2020 |
| Crnr Ltd | Arts & recreation | 2021 |
| Crochet & Yumak Ltd | Wholesale & retail | 2015 |
| Crofters Court (Management Co) Limited | Households | 1992 |
| Crofton Albion Sports & Social Club Limited | Arts & recreation | 2020 |
| Crofton Myers Training Ltd | Education | 2012 |
| Cromwell Estate Agency Limited | Real estate | 2013 |
| Cronoslink Limited | Information & communication | 2022 |