| Cusheba Care Limited | Health & social care | 2014 |
| Custom & Basket Ltd | Wholesale & retail | 2025 |
| Custom Access Security Ltd | Administrative & support | 2023 |
| Custom Box Service Limited | Manufacturing | 2025 |
| Custom Fitters Limited | Construction | 2008 |
| Custom Sportswear Ltd | Wholesale & retail | 2019 |
| Customised Carpentry Ltd | Construction | 2017 |
| Customsize Ltd | Manufacturing | 2022 |
| CUT Corner Ltd | Other services | 2025 |
| Cuteeet UK Ltd | Professional & scientific | 2025 |
| Cutmore Carpentry Limited | Manufacturing | 2014 |
| Cutter Microdot Limited | Information & communication | 2020 |
| Cutting Crew (Luton) Limited | Other services | 2002 |
| CV Comms Limited | Manufacturing | 2000 |
| CW Properties (Luton) Ltd | Real estate | 2023 |
| CXM Tech Services Holdings Ltd | Information & communication | 2000 |
| CXM Tech Services UK Ltd | Information & communication | 1998 |
| CY - TEK Solutions Limited | Information & communication | 2000 |
| Cyan UK Group Ltd | Administrative & support | 2017 |
| Cybeds CIC | Information & communication | 2026 |
| Cyber Gadgets Limited | Wholesale & retail | 2021 |
| Cyber Partners Ltd | Other services | 2014 |
| Cyber Spark Solutions Tech Ltd | Construction | 2023 |
| Cybercloud Technologies Ltd | Administrative & support | 2022 |
| Cyberlogix Consultancy Services Ltd | Information & communication | 2025 |
| Cyberseller Limited | Wholesale & retail | 2025 |
| Cyberwavve IT Limited | Information & communication | 2017 |
| Cyborgsit Ltd | Information & communication | 2018 |
| Cybron International Limited | Information & communication | 2023 |
| Cyeco Wash Ltd | Administrative & support | 2025 |
| Cygnus Pharma Ltd | Wholesale & retail | 2018 |
| Cymatech Ltd | Information & communication | 2025 |
| Cyphera Ltd | Wholesale & retail | 2025 |
| CYS Group Ltd | Administrative & support | 2017 |
| CYS Recruitment Ltd | Administrative & support | 2020 |
| CYS Security Ltd | Administrative & support | 2009 |
| CYZ Transport Ltd | Transport & logistics | 2020 |
| CZ Luton Ltd | Wholesale & retail | 2015 |
| Czajkowski Transport Ltd | Transport & logistics | 2014 |
| Czako Books Ltd | Construction | 2022 |
| Czako Fruit & VEG Ltd | Wholesale & retail | 2022 |
| Czech Mate Limited | Financial services | 1991 |
| Czechmade Limited | Extraterritorial | 1994 |
| D & a Communications Ltd | Construction | 2010 |
| D & a Consultants Ltd | Professional & scientific | 2011 |
| D & B Plastering and Drylining Ltd | Construction | 2018 |
| D & D Accountancy Limited | Professional & scientific | 2020 |
| D & D Building & Property Maintenance Ltd | Construction | 2017 |
| D & G Construction (Luton) Limited | Construction | 2017 |
| D & L Contract Services Limited | Water & waste | 2010 |
| D & L Courier Support Services Ltd | Other services | 2022 |
| D & L Couriers Services Ltd | Administrative & support | 2018 |
| D & S Residential Properties Limited | Real estate | 2022 |
| D & T Hair Ltd | Other services | 2021 |
| D an D Property Management Limited | Real estate | 2024 |
| D and D Personnel Ltd | Construction | 2023 |
| D and D Transport Specialists Ltd | Transport & logistics | 2021 |
| D and M Tailoring and Alteration Ltd | Manufacturing | 2024 |
| D Auto Repairs Ltd | Wholesale & retail | 2019 |
| D E Signs & Labels Limited | Manufacturing | 2003 |
| D Fannin Engineering Limited | Manufacturing | 2014 |
| D Harlee's Ltd | Wholesale & retail | 2026 |
| D I C Real Estate Limited | Real estate | 2017 |
| D M Advice Centre Ltd | Financial services | 2024 |
| D M C Plant Hire Ltd | Administrative & support | 2014 |
| D M Trading Services Ltd | Transport & logistics | 2018 |
| D S Robinson Services Limited | Professional & scientific | 2013 |
| D S Waste Limited | Water & waste | 2023 |
| D Singh Construction Services Ltd | Construction | 2024 |
| D W Cleaners (DWC) Ltd. | Administrative & support | 2015 |
| D W L Plastering Ltd | Construction | 2019 |
| D&A Quality Lofts Limited | Construction | 2018 |
| D&Avjot Ltd | Real estate | 2019 |
| D&C Smart Repair Ltd | Wholesale & retail | 2025 |
| D&D Dynamic Build Ltd | Construction | 2026 |
| D&D POP Construct Ltd | Construction | 2026 |
| D&D UK Cars Limited | Wholesale & retail | 2019 |
| D&D.It Ltd | Information & communication | 2021 |
| D&Dlogistix Ltd | Construction | 2025 |
| D&G 2018 Ltd | Financial services | 2018 |
| D&G Bucoveanu Transport Ltd | Transport & logistics | 2018 |
| D&G Investment Property Limited | Real estate | 2025 |
| D&G Support Team (Relocation) Ltd | Administrative & support | 2017 |
| D&J Star Nails Ltd | Other services | 2024 |
| D&M Fashion Enterprise Limited | Wholesale & retail | 2017 |
| D&M Fast Food Ltd | Hospitality | 2020 |
| D&M KOD Limited | Health & social care | 2015 |
| D&N Partners Global Ltd | Wholesale & retail | 2025 |
| D&N Plumbing Ltd | Construction | 2019 |
| D&R Prime Solutions Ltd | Construction | 2026 |
| D&S Team Ltd | Construction | 2022 |
| D&V Capital Finance Ltd | Construction | 2024 |
| D&V Property Acquisitions Ltd | Real estate | 2023 |
| D'Lighthouse Solutions Limited | Professional & scientific | 2011 |
| D'N'N Garden Services Ltd | Administrative & support | 2025 |
| D'Veryplace Hair Salon Ltd | Other services | 2023 |
| D-Alders Limited | Wholesale & retail | 2023 |
| D. M. MC Donald Haulage Ltd | Transport & logistics | 2025 |
| D.A Wellness Chiro Ltd | Health & social care | 2025 |
| D.B Delivery Services Limited | Construction | 2016 |