| Curtis Solutions Ltd | Construction | 2020 |
| Curtis Steve Consulting LLP | | 2019 |
| Cushty Couriers Ltd | Transport & logistics | 2020 |
| Custom Play Dates Ltd | Health & social care | 2021 |
| Customer Strategy Network Limited | Information & communication | 2015 |
| Customtakeawaypackaging Ltd | Manufacturing | 2026 |
| Cutbox Limited | Information & communication | 2020 |
| Cutplan Ltd | Information & communication | 2026 |
| Cuztler Ltd | Administrative & support | 2023 |
| CV JET Ltd | Wholesale & retail | 2025 |
| CV6 Holdings Ltd | Construction | 2020 |
| CVC Garage Ltd | Wholesale & retail | 2026 |
| Cvcon Ltd | Construction | 2025 |
| CVD Solutions Ltd | Wholesale & retail | 2026 |
| CVM Interiors Ltd | Construction | 2019 |
| CVM Road Ltd | Transport & logistics | 2024 |
| CVM Services Ltd | Wholesale & retail | 2023 |
| CVP Consulting Limited | Construction | 2015 |
| CVS Holdings Limited | Professional & scientific | 2000 |
| CW Audit Solutions Limited | Administrative & support | 2018 |
| CW Consulting Box Limited | Information & communication | 2012 |
| CW Executive Finance Limited | Financial services | 2015 |
| CW Installations MK Limited | Construction | 2014 |
| Cwaf Limited | Construction | 2010 |
| Cwbb Property Ltd | Construction | 2026 |
| Cwci Ltd | Real estate | 2026 |
| CWF Estate Planning Limited | Administrative & support | 2014 |
| Cwmtawe Dental Practice Ltd | Health & social care | 2008 |
| Cworking Limited | Information & communication | 2016 |
| CWR Consultancy Ltd | Administrative & support | 2017 |
| Cwtch Care Home Ltd | Health & social care | 2024 |
| Cwtcm Acupuncture and Herbs Ltd | Health & social care | 2026 |
| Cxconversion Limited | Professional & scientific | 2015 |
| Cyber Toolkit Ltd | Information & communication | 2026 |
| Cyberquadrant Ltd | Information & communication | 2025 |
| Cybersonic Limited | Information & communication | 1997 |
| Cybervaults Ltd | Wholesale & retail | 2026 |
| Cybex International Service Limited | Transport & logistics | 2006 |
| Cybist Ltd | Wholesale & retail | 2020 |
| Cybrux Limited | Information & communication | 2024 |
| Cyclon GIL Ltd | Transport & logistics | 2015 |
| Cyclone Construction Ltd | Construction | 2023 |
| Cygnet Mews (Phase 2) Management Company Limited | Households | 2014 |
| Cygnus-Ai Business Solutions Ltd | Information & communication | 2023 |
| CYL Interiors Ltd | Professional & scientific | 2015 |
| Cynosure Healthcare Services Ltd | Hospitality | 2014 |
| Cynthia Spencer Hospice Charity | Health & social care | 2017 |
| Cynthia Spencer Hospice Ventures Limited | Wholesale & retail | 2000 |
| Cypher IPX Solutions Limited | Construction | 2025 |
| Cyprianis Enterprises Limited | Hospitality | 2013 |
| Cyretech Ltd | Professional & scientific | 2006 |
| Cytos Construction Ltd | Construction | 2016 |
| Cyzek Global Services Ltd | Administrative & support | 2025 |
| CZ Composites Ltd | Professional & scientific | 2024 |
| Célami Ltd | Wholesale & retail | 2026 |
| D & a Tanning Ltd | Financial services | 2023 |
| D & C Heating Services Limited | Construction | 2014 |
| D & D Consultancy, Training & Publishing Ltd | Information & communication | 2021 |
| D & E Transport Limited | Transport & logistics | 2025 |
| D & I Ursinschi Limited | Real estate | 2017 |
| D & J Auto Recruitment Ltd | Administrative & support | 2017 |
| D & L Windows & Doors Ltd | Construction | 2019 |
| D & P Property Development Ltd | Construction | 2020 |
| D & S Cooling Ltd | Manufacturing | 2024 |
| D & S Parker Limited | Real estate | 1990 |
| D a S Developments Ltd | Construction | 2025 |
| D and G Deliveries Ltd | Transport & logistics | 2019 |
| D and S Tyres (Northampton) Limited | Wholesale & retail | 2010 |
| D Archer Electrical Engineers & Contractors Ltd | Other services | 2014 |
| D B J Services Limited | Manufacturing | 2004 |
| D B York Ltd | Construction | 2009 |
| D Blakemore Ltd | Construction | 2026 |
| D Buildream Customs Ltd | Wholesale & retail | 2024 |
| D Clayson Services Ltd | Professional & scientific | 2025 |
| D Criclevit Ltd | Transport & logistics | 2025 |
| D D K Facilities Limited | Construction | 2011 |
| D Eales on Wheels Northampton Ltd | Wholesale & retail | 2024 |
| D Eele HS Ltd | Professional & scientific | 2026 |
| D Electrics Northants Ltd | Administrative & support | 2025 |
| D Facades Limited | Manufacturing | 2017 |
| D Fleet Cleaning Services Ltd | Administrative & support | 2016 |
| D Howard IT Limited | Information & communication | 2013 |
| D J Astle Limited | Professional & scientific | 2021 |
| D J Hicks Ltd | Information & communication | 2019 |
| D K Brickwork Limited | Construction | 2015 |
| D M Hospitality & Services Ltd | Hospitality | 2024 |
| D P Allison Plumbing and Construction Limited | Construction | 2015 |
| D P Finance Limited | Financial services | 2006 |
| D POP Trans Ltd | Administrative & support | 2018 |
| D R Carpentry and Kitchens Ltd | Construction | 2024 |
| D R Grip Limited | Professional & scientific | 2013 |
| D R Morris Electrical Services Limited | Construction | 2010 |
| D R Morris Holdings Ltd | Financial services | 2024 |
| D R Roofing Ltd | Construction | 2011 |
| D R Studios Limited | Information & communication | 2007 |
| D Tasker Roofing Services Limited | Construction | 2017 |
| D Tear Ltd | Real estate | 2008 |
| D to F Limited | Construction | 2008 |
| D Tompkins Catering Ltd | Hospitality | 2019 |
| D Toner Transport Limited | Transport & logistics | 2016 |