| Crestwood Group Ltd | Wholesale & retail | 2025 |
| Cribbens Group Limited | Construction | 2024 |
| Cribcards Ltd | Education | 2023 |
| Cricket Flow Ltd | Wholesale & retail | 2024 |
| Criminal Investigation and Paralegal Services Limited | Professional & scientific | 2020 |
| Crismab Limited | Education | 2016 |
| Crismedical Limited | Health & social care | 2015 |
| Cristian TAB Ltd | Transport & logistics | 2015 |
| Crossroads Farm Developments Limited | Wholesale & retail | 2001 |
| Crossways (Harborough) Limited | Construction | 2005 |
| Crowco Ltd | Hospitality | 2026 |
| Crown Holdings (Midlands) Limited | Financial services | 2016 |
| Crown Pharmaceuticals Limited | Real estate | 2001 |
| Crowned in Glory Ltd | Wholesale & retail | 2025 |
| Crowson Developments Limited | Construction | 2018 |
| Croyland Auto Megastore Limited | Wholesale & retail | 2004 |
| Croyland Car Megastore Limited | Wholesale & retail | 2005 |
| Croyland Motors Limited | Wholesale & retail | 1958 |
| Croyland Rentals Limited | Real estate | 2011 |
| CRP Decorators Ltd | Construction | 2024 |
| CRT Management Services Ltd | Information & communication | 2022 |
| CRT Masonry Ltd | Manufacturing | 2020 |
| Crumb and Tumble Ltd | Hospitality | 2026 |
| Crystal FOX Window Cleaning Limited | Administrative & support | 2019 |
| Crystal Natural Paving UK Ltd | Wholesale & retail | 2021 |
| Crystal Planet Ltd | Wholesale & retail | 2022 |
| CS Construction Management Limited | Administrative & support | 2019 |
| Csbs Ltd | Information & communication | 2003 |
| CSI80 Ltd | Health & social care | 2022 |
| CST Physio & Pilates Ltd | Health & social care | 2025 |
| CTB Installations Ltd | Construction | 2007 |
| Ctrl Cosmetics Ltd | Other services | 2021 |
| Cuetopia Ltd | Arts & recreation | 2022 |
| Cullinane Business Services Limited | Professional & scientific | 2018 |
| Culshaw Consulting Ltd | Information & communication | 2026 |
| Culverden Hall Investments Limited | Real estate | 2024 |
| Cumberland Platforms Limited | Manufacturing | 2011 |
| Cumming Associates Limited | Professional & scientific | 2014 |
| Cupi Services Limited | Wholesale & retail | 2017 |
| Curaflow Health Limited | Professional & scientific | 2025 |
| Current Cravings Ltd | Hospitality | 2024 |
| Cushion Fluffers Ltd | Professional & scientific | 2020 |
| Custec Design Limited | Professional & scientific | 2002 |
| Custom Energy Solutions Limited | Professional & scientific | 2011 |
| Cutting Edge Guitar Limited | Other services | 2012 |
| CV Consulting (Design, Build & Maintenance) Ltd | Construction | 2019 |
| CV Investment Group Limited | Real estate | 2025 |
| CV Renovation Limited | Construction | 2024 |
| CV Transport Ltd | Transport & logistics | 2024 |
| CVC Couriers Ltd | Transport & logistics | 2025 |
| Cvpmedical Ltd | Health & social care | 2018 |
| CWT Tech Solutions Limited | Information & communication | 2025 |
| Cyber EYE Security Limited | Administrative & support | 2006 |
| Cybersmith Ltd | Information & communication | 2022 |
| Cynmvu Limited | Health & social care | 2022 |
| Cyril Thomas Ltd | Health & social care | 2010 |
| Cytec Recruitment Ltd | Professional & scientific | 2008 |
| D & CD Cunnington Surveyors Limited | Other services | 2007 |
| D & M Jones Carpentry Services Ltd | Construction | 2012 |
| D a Heating Limited | Construction | 2014 |
| D and S Turner Limited | Construction | 2007 |
| D B Bespoke Bathrooms Ltd | Construction | 2008 |
| D B Export Collection Holdings Ltd | Financial services | 2014 |
| D Barlow Installations Limited | Construction | 2010 |
| D Blakeston Plastering & Drylining Limited | Construction | 2017 |
| D Curtis Holdings Ltd | Financial services | 2020 |
| D Curtis Property Limited | Real estate | 2017 |
| D Frayne Haulage Ltd | Transport & logistics | 2003 |
| D H & S (Northamptonshire) Limited | Public administration | 2020 |
| D J Teck Ltd | Information & communication | 2012 |
| D Key Group Ltd | Professional & scientific | 2026 |
| D M Anderson Electrical Services Ltd | Construction | 2020 |
| D N a Transport Limited | Transport & logistics | 2022 |
| D Wisniewski Ltd | Wholesale & retail | 2015 |
| D&A Innovations Ltd | Construction | 2025 |
| D'S Build Limited | Construction | 2022 |
| D. & J. Brough Limited | Construction | 1958 |
| D.A.S International Scaffolding Ltd | Construction | 2023 |
| D.E.Limited | Extraterritorial | 1983 |
| D.K.Frampton Limited | Wholesale & retail | 1972 |
| D.K.N. Transport Limited | Transport & logistics | 2003 |
| D.M.M. Heating & Plumbing Ltd | Construction | 2015 |
| D.O.T.M. Limited | Financial services | 2011 |
| D.R. Harrod Tractors LLP | | 2002 |
| D8 Developments Ltd | Construction | 2022 |
| Da&Al Ltd | Real estate | 2025 |
| Dacs Group Ltd | Information & communication | 2018 |
| Dadsha Retail Limited | Wholesale & retail | 2019 |
| Daeron Social Limited | Information & communication | 2025 |
| Daily Stop Shop Limited | Wholesale & retail | 2017 |
| Dallas IKE Limited | Transport & logistics | 2019 |
| Dallas Signs Ltd | Professional & scientific | 2025 |
| Dalu Healthcare Services Ltd | Health & social care | 2016 |
| Damax Building Solutions Ltd | Construction | 2023 |
| Damo Properties Limited | Real estate | 2022 |
| Dampology Ltd | Construction | 2026 |
| Damstan Trans Ltd | Transport & logistics | 2017 |
| Danair Limited | Construction | 2016 |
| Danhodotrans Ltd | Transport & logistics | 2026 |
| Daniel C Tiling Limited | Construction | 2017 |