| COR Building Surveys Ltd | Professional & scientific | 2022 |
| Coral Lace Cakes Ltd | Manufacturing | 2019 |
| Coral Training Ltd | Wholesale & retail | 2008 |
| Corbec Electrical Ltd | Construction | 2012 |
| Corcoran Development Services Limited | Professional & scientific | 2018 |
| Core Hair Ltd | Other services | 2026 |
| Core Marine Ltd | Manufacturing | 2020 |
| Coreseed Ltd | Information & communication | 2026 |
| Corfu Direct Limited | Hospitality | 2004 |
| Corina Patel Liew Consulting Ltd | Professional & scientific | 2009 |
| Corkett Scaffolding Limited | Construction | 2004 |
| Corkshield Ltd | Construction | 2016 |
| Corner Media Limited | Professional & scientific | 2020 |
| Cornerstone Care Ltd | Health & social care | 2020 |
| Cornerstone Drawing Associates Ltd | Professional & scientific | 2020 |
| Cornish Garden Rooms Limited | Construction | 2021 |
| Cornwall House RMC Limited | Households | 2017 |
| Corpe Ltd | Real estate | 2014 |
| Corporate Catering Limited | Hospitality | 2013 |
| Corry Motors Services Limited | Manufacturing | 2005 |
| Cortex Projects Limited | Information & communication | 2016 |
| Corvus Advisory Ltd | Professional & scientific | 2025 |
| Cosily Ltd | Transport & logistics | 2019 |
| COSMO21 Ltd | Transport & logistics | 2020 |
| Cosmos Business Connection Ltd | Wholesale & retail | 2014 |
| Cost Reduction Warehouse Ltd | Other services | 2020 |
| Cotax Limited | Extraterritorial | 2003 |
| Cottage Farm Estates Ltd | Real estate | 2018 |
| Cottage Farm Container Storage Ltd | Transport & logistics | 2023 |
| Cottage Orne Limited | Hospitality | 2022 |
| Coulon Properties Ltd | Real estate | 2019 |
| Country Inn Hospitality Ltd | Hospitality | 2026 |
| County Bathrooms Limited | Construction | 2003 |
| County Grove (Aylesbury) Management Company Limited | Households | 2016 |
| Covariant AI Ltd. | Professional & scientific | 2022 |
| Covert Productions Limited | Information & communication | 2020 |
| Coverworld Management Services Ltd | Real estate | 2000 |
| Cowle Engineering Ltd | Professional & scientific | 2018 |
| Coworkerandme Limited | Information & communication | 2026 |
| Cozy Cabin Pubs Ltd | Hospitality | 2024 |
| CP Direct Ltd | Wholesale & retail | 2022 |
| CPD Consultancy Ltd | Professional & scientific | 2025 |
| CPT Group Ltd | Professional & scientific | 2018 |
| CR Redhill Construction Limited | Construction | 2019 |
| Crafted Spaces Architecture and Planning Ltd | Professional & scientific | 2017 |
| Craftwood Creations Ltd | Construction | 2023 |
| Crafty Bars Limited | Hospitality | 2018 |
| Crafty Tech Limited | Professional & scientific | 2002 |
| Crane Healthcare Services Limited | Hospitality | 2020 |
| Crane Housing CIC | Hospitality | 2023 |
| Cranscombe Ltd | Administrative & support | 2011 |
| Cranwell Baker LLP | | 2025 |
| Crazy Cat Software Limited | Information & communication | 2023 |
| CRD Accounting Services Limited | Professional & scientific | 2002 |
| Create Carpentry & Joinery Ltd | Manufacturing | 2025 |
| Create Film & Photography Ltd | Professional & scientific | 2023 |
| Creating Smiles Ltd | Health & social care | 2013 |
| Creative Driveways & Patios Ltd | Construction | 2019 |
| Creative Living and Design Limited | Construction | 2018 |
| Credit and Collection Services Limited | Administrative & support | 2025 |
| Credit Collection Services Limited | Information & communication | 2024 |
| Crendon Conservatories Limited | Construction | 2006 |
| Crendon Furniture Outlet Ltd | Wholesale & retail | 2011 |
| Crendon House Mortgages Ltd | Financial services | 2008 |
| Crendon Motors Limited | Wholesale & retail | 2004 |
| Crendon Road Management Company Limited | Administrative & support | 2005 |
| Creslow Contracting Ltd | Construction | 2024 |
| Creslow Park Limited | Real estate | 2016 |
| Creslow Skunkworks CIC | Information & communication | 2025 |
| Cressacres Carp Syndicate Limited | Agriculture & fishing | 2020 |
| Cretzu Ltd | Construction | 2018 |
| Crew&Deck Ltd | Construction | 2015 |
| Creyke Beck Solar Ltd | Energy | 2021 |
| CRI & GAB Ltd | Transport & logistics | 2022 |
| Crisp Networking Limited | Information & communication | 2007 |
| Cristian Construction Limited | Construction | 2014 |
| CRK Entertainment Limited | Professional & scientific | 2023 |
| CRM Services (UK) Limited | Construction | 2013 |
| Crock Traders Limited | Financial services | 2012 |
| Crockwell Hill Solar Farm Ltd | Construction | 2023 |
| Croft Residents Limited | Households | 1971 |
| Croftcade Limited | Wholesale & retail | 2018 |
| Croftley Projects Limited | Construction | 2019 |
| Crookham Consulting Ltd | Administrative & support | 2023 |
| Cross Graphics Limited | Wholesale & retail | 1978 |
| Cross Rein Solar Farm Limited | Energy | 2023 |
| Crossbow Solutions Ltd | Construction | 2025 |
| Crouch&Co SURVEYORS25 Ltd | Real estate | 2025 |
| Crown Cabs Travel Limited | Transport & logistics | 2011 |
| Crown Coach Travel Limited | Transport & logistics | 2023 |
| Crown Customs Ltd | Manufacturing | 2022 |
| Crown Executive Chauffeur Cars Ltd | Transport & logistics | 2008 |
| Crown Group Legal Services Ltd | Wholesale & retail | 2015 |
| Crown Rose Court Management Company Limited | Households | 1987 |
| Crownmede Developments Limited | Real estate | 2016 |
| Crownstone Developements Group Limited | Construction | 2024 |
| Croxley Hall Fisheries Limited | Agriculture & fishing | 2019 |
| CRT Pioneer Fund LP | | 2012 |
| CRT Pioneer GP Limited | Professional & scientific | 2012 |
| Cruithne Ltd | Health & social care | 2019 |