| Cowlease Ltd | Administrative & support | 2021 |
| Coworker Ltd | Professional & scientific | 2026 |
| COX & Wright Limited | Manufacturing | 1945 |
| COX Mortgages Ltd | Financial services | 2026 |
| CPD Brickwork Limited | Construction | 2026 |
| Cqms Investments Limited | Real estate | 2022 |
| Crabbett Wood Limited | Financial services | 2016 |
| Cracking Slate Ltd | Arts & recreation | 2025 |
| Cradloop UK Ltd | Manufacturing | 2019 |
| CRAFTS4KIDS Ltd | Wholesale & retail | 2014 |
| Craven Capital Limited | Financial services | 2010 |
| Craven Snarey LLP | | 2006 |
| Cray Builders Limited | Construction | 1998 |
| CRE Products Limited | Manufacturing | 2006 |
| Creative Holdings (Grantham) Limited | Extraterritorial | 2016 |
| Creative Misrule Ltd | Professional & scientific | 2024 |
| Creative Products Employee Ownership Trustee Limited | Professional & scientific | 2025 |
| Creative Products Group Limited | Financial services | 2024 |
| Creative Products Limited | Wholesale & retail | 2009 |
| Credo Claims Limited | Financial services | 2012 |
| Creeperhost Ltd | Information & communication | 2013 |
| Cresta Run Limited | Financial services | 2012 |
| Crewood Underwriting Limited | Financial services | 2009 |
| Cricket World Limited | Extraterritorial | 2007 |
| Crime Reduction Enterprise Ltd | Professional & scientific | 2015 |
| Crimson Kings (Midlands) Ltd | Administrative & support | 2021 |
| Crisp Financial Limited | Financial services | 2025 |
| Crispwell IP Ltd | Administrative & support | 2022 |
| Crockateggal Ltd | Transport & logistics | 2021 |
| Crop Creative Ltd | Professional & scientific | 2019 |
| Crop-England Ltd | Agriculture & fishing | 2019 |
| Croupier Underwriting Limited | Financial services | 2001 |
| Crown Homeworks Interiors Limited | Wholesale & retail | 2021 |
| Crown Homeworks Limited | Construction | 2017 |
| Crumb 137 Ltd | Professional & scientific | 2024 |
| Crwp (South Witham) Limited | Real estate | 2022 |
| Cryer Surveying Limited | Construction | 2019 |
| Crystal Mini Market Ltd | Wholesale & retail | 2024 |
| CRZ Holdings Ltd | Hospitality | 2022 |
| Cullen Property Investments Limited | Real estate | 2015 |
| Custom GB Creations Ltd | Wholesale & retail | 2022 |
| Custom Interiors Stamford Ltd | Construction | 2023 |
| CUT 'N' Clear Limited | Agriculture & fishing | 2005 |
| Cutsie Girls Clothing Ltd | Wholesale & retail | 2024 |
| CVG Pubs Limited | Hospitality | 2023 |
| CWB Estates Limited | Real estate | 2020 |
| CWH Property Surveyors Limited | Professional & scientific | 2026 |
| CWH Surveyors LLP | | 2013 |
| D & S Farms Limited | Agriculture & fishing | 1965 |
| D D BYE Limited | Public administration | 2020 |
| D M Suddaby Limited | Construction | 2003 |
| D Temperton Plumbing Services Limited | Construction | 2015 |
| D&B Farming Company Limited | Agriculture & fishing | 2014 |
| D&S Johnson & Sons Ltd | Financial services | 2018 |
| D-Tech Electrical Contractors Limited | Professional & scientific | 2013 |
| D-Tech Electrical Holdings Limited | Financial services | 2017 |
| D-Tech Holdings Limited | Financial services | 2017 |
| D-Tech Property Limited | Real estate | 2017 |
| D.G.S. Engineering Limited | Professional & scientific | 2001 |
| D.R. Leighton LLP | | 2006 |
| D13 Solutions Limited | Professional & scientific | 2015 |
| DA Autotraders Ltd | Wholesale & retail | 2020 |
| DAG Plumbing and Welding Services Ltd | Construction | 2021 |
| DAI Graphic Design Limited | Professional & scientific | 2012 |
| Daily Delights Food Ltd | Wholesale & retail | 2025 |
| Daisy's Purpose Ltd | Extraterritorial | 2024 |
| Dale Farm Holdings Ltd | Financial services | 2021 |
| Damavand LLP | | 2021 |
| DAN89 Ltd | Hospitality | 2021 |
| Dance J Events CIC | Education | 2024 |
| Dancing in the Street Limited | Wholesale & retail | 2005 |
| Daneplast Limited | Manufacturing | 1988 |
| Daniel&M Trans Ltd | Transport & logistics | 2020 |
| Dare&Dare Limited | Professional & scientific | 2013 |
| Dareway Properties Limited | Construction | 1990 |
| Darin Developments Limited | Real estate | 2025 |
| Darrington Properties Limited | Real estate | 2001 |
| Dart Property Solutions Ltd | Households | 2020 |
| Dataford Ltd | Information & communication | 2020 |
| Datatech Electrical Limited | Construction | 2013 |
| Datcom LLP | | 2010 |
| Davaar Solutions Limited | Administrative & support | 2015 |
| Dave Edwards Racing Limited | Arts & recreation | 2025 |
| David Qian Co Limited | Manufacturing | 2024 |
| David Todd Architecture Ltd | Professional & scientific | 2010 |
| Davidson & Searsons Ltd | Real estate | 2022 |
| Dawn's Cuisine Ltd | Hospitality | 2004 |
| Dawnint UK Limited | Wholesale & retail | 2026 |
| Dawson Educational Psychology Services Ltd | Education | 2019 |
| Day LEE Enterprise Limited | Wholesale & retail | 2013 |
| Db/Webservices Limited | Wholesale & retail | 2020 |
| DBC Plant Hire Ltd | Construction | 2009 |
| DBM Construction Limited | Construction | 2011 |
| DBM Plant Hire Ltd | Administrative & support | 2016 |
| Dcjoiners Ltd | Construction | 2019 |
| DE Matos Pipefitters Limited | Construction | 2025 |
| DE Witts Property Consultancy Limited | Real estate | 2013 |
| Debbie Johnson Limited | Administrative & support | 2017 |
| Decorative Country Living Ltd | Wholesale & retail | 2000 |
| Decshop Ltd | Wholesale & retail | 2019 |