| Cleaners Passion Ltd | Administrative & support | 2025 |
| Clippers Limited | Other services | 2017 |
| CMK Services Ltd | Professional & scientific | 2025 |
| CMT Ventures Limited | Arts & recreation | 2010 |
| Coast@Jwz Limited | Hospitality | 2021 |
| Cocina DE Madre Limited | Wholesale & retail | 2015 |
| Code & Cloud Ltd | Information & communication | 2022 |
| Codles Ltd | Wholesale & retail | 2019 |
| Cognatum Estates II Limited | Administrative & support | 2020 |
| Cognatum Estates III Limited | Administrative & support | 2022 |
| Cognatum Estates Limited | Administrative & support | 2008 |
| Cognatum Projects Limited | Construction | 2016 |
| Cognatum Property Limited | Real estate | 2005 |
| Cognatum Services Limited | Other services | 2018 |
| Collins and Lane Builders Ltd | Construction | 2017 |
| Comp-A-Tent Ltd | Professional & scientific | 2015 |
| Comparts International Limited | Wholesale & retail | 2007 |
| Complete Cleaning and Clearance Ltd | Extraterritorial | 2019 |
| Comrades Club Limited(The) | Hospitality | 1958 |
| Concord Limited | Real estate | 2024 |
| Concorde Limited | Construction | 2025 |
| Connect Catering Limited | Hospitality | 1989 |
| Connect Purchasing Limited | Wholesale & retail | 2013 |
| Connx Business Solutions Limited | Information & communication | 2015 |
| Consultancy TAW Ltd | Professional & scientific | 2025 |
| Contemporary Steel Doors Limited | Other services | 2022 |
| Contract and Commercial Services Ltd | Professional & scientific | 2019 |
| Contronics Limited | Manufacturing | 1978 |
| Cordmount Limited | Real estate | 1997 |
| Corn Exchange Wallingford Ltd | Arts & recreation | 1976 |
| Coulton Plumbing and Heating Services Ltd | Construction | 2022 |
| Cowley Advisors Limited | Financial services | 2019 |
| COX Crew Ltd | Real estate | 2024 |
| CP Property Group Limited | Households | 2024 |
| Cpnewson Ltd | Financial services | 2023 |
| Cracking Campus Ltd | Administrative & support | 2025 |
| Craghert Limited | Extraterritorial | 2008 |
| Cranford School | Education | 1980 |
| Crazy Quiffs MK1 Golf Parts Emporium Limited | Wholesale & retail | 2007 |
| CRB Medicolegal Limited | Other services | 2025 |
| Creating Love Limited | Other services | 2019 |
| Crill Holdings Limited | Real estate | 2018 |
| Cross Country Caravans (Bristol) Limited | Professional & scientific | 1975 |
| Cross Country Caravans Limited | Hospitality | 1970 |
| Crowmarsh Battle Farms Limited | Agriculture & fishing | 1973 |
| Crowmarsh Investments Ltd | Financial services | 2017 |
| Crowmarsh PUB Company Limited | Administrative & support | 2019 |
| Crowmarsh Tyres Limited | Wholesale & retail | 2024 |
| Csioa Developments Limited | Real estate | 2024 |
| Cslv Ltd | Financial services | 2024 |
| CTB Construction Group Ltd | Construction | 2025 |
| Ctrl Creative Camden Ltd | Professional & scientific | 2020 |
| Ctrl Creative Glasgow Ltd | Professional & scientific | 2025 |
| Cubitt Capital Limited | Financial services | 2014 |
| Cultureledger Limited | Other services | 2025 |
| Cunninghams Epos Group Limited | Other services | 1975 |
| Curve Group Ltd | Manufacturing | 2025 |
| Customs Logic Ltd | Professional & scientific | 2015 |
| Cutlerarch Limited | Professional & scientific | 2000 |
| Cwhr Ltd | Administrative & support | 2022 |
| Cymbeline Consulting Limited | Professional & scientific | 2002 |
| CZ Bespoke Carpentry Ltd | Construction | 2026 |
| D. a. V. Digital Limited | Other services | 2017 |
| D2E Agency Ltd | Professional & scientific | 2022 |
| Dance Connection Studios Ltd | Education | 2018 |
| Dark Fable Productions Ltd | Information & communication | 2025 |
| Dark Horse Roastery Ltd | Manufacturing | 2016 |
| Darren Bryan Security Services Limited | Administrative & support | 2011 |
| Data Dimension Ltd | Information & communication | 2003 |
| Data Programme Management Ltd | Information & communication | 2020 |
| Dataflow Events Ltd | Transport & logistics | 1996 |
| Datasec Partners Ltd | Information & communication | 2023 |
| Datchet Green Management Company Limited | Households | 1995 |
| David Barrington Limited | Administrative & support | 2008 |
| David Lowe Coach Limited | Information & communication | 2014 |
| Decentralize Digital Limited | Professional & scientific | 2022 |
| Decision Advantage Solutions Limited | Information & communication | 2016 |
| Definite Developments Limited | Construction | 2022 |
| Definite Finance Company Limited | Real estate | 1989 |
| Delabie UK Limited | Manufacturing | 1983 |
| Delhi Brasserie (Wallingford) Ltd | Hospitality | 2011 |
| Deluxe Holiday Homes Limited | Other services | 2018 |
| Deluxe Holiday Homes Services Limited | Hospitality | 2020 |
| Dering Properties (Abingdon) Limited | Real estate | 2017 |
| Dering Properties (Banbury) Limited | Real estate | 2016 |
| Dering Properties (Crawley) Limited | Real estate | 2016 |
| Design Works Gaming (UK) Ltd | Information & communication | 2018 |
| Designstock Limited | Real estate | 1987 |
| Dexory Limited | Professional & scientific | 2015 |
| Didcot Glass & Glazing Limited | Construction | 2009 |
| Digiconomy Limited | Professional & scientific | 2018 |
| Digitalicx Limited | Information & communication | 2015 |
| Dimond Movers Ltd | Transport & logistics | 2021 |
| Dine OUT at Home Ltd | Manufacturing | 2022 |
| Directive Finance Ltd | Professional & scientific | 2022 |
| Distributed Communication Systems Limited | Professional & scientific | 2009 |
| Djjh Consulting Limited | Real estate | 2012 |
| DLG Investigations Group Ltd | Administrative & support | 2019 |
| DLG Tracing & Investigations Limited | Administrative & support | 2021 |
| DM Composite Engineering Ltd | Manufacturing | 2014 |