| Culgun Ltd | Manufacturing | 2012 |
| Cumulus Numbers Ltd | Extraterritorial | 1999 |
| CUP Alloys (Metal Joining) Limited | Wholesale & retail | 2013 |
| Curious Design Company Limited | Professional & scientific | 2017 |
| Current Cuisine Ltd | Hospitality | 2025 |
| Curzon Clarke Engineering Limited | Construction | 1996 |
| Custom Computers (Mansfield) Limited | Information & communication | 2008 |
| Custom Cooling Limited | Construction | 2025 |
| Custom Vehicle Builds Ltd | Wholesale & retail | 2025 |
| Cuteish Ltd | Wholesale & retail | 2022 |
| CW OFF Pitch Limited | Professional & scientific | 2024 |
| CWM Wealth Management Limited | Financial services | 2021 |
| Cwtch Property Ltd | Real estate | 2021 |
| CY GD Ltd | Hospitality | 2026 |
| Cyberpunk Homes Ltd | Wholesale & retail | 2026 |
| CYK Spray Ltd. | Other services | 2021 |
| Cyrus Holdings Group Ltd | Construction | 2025 |
| Czlei Limited | Other services | 2024 |
| D & C Lettings Ltd | Real estate | 2022 |
| D & C Security Systems Limited | Construction | 2018 |
| D & L Outdoor Creations Limited | Administrative & support | 2017 |
| D & M Asset Holdings Ltd | Real estate | 2026 |
| D & S Storage (Holdings) Limited | Professional & scientific | 2000 |
| D Harwood Plumbing & Heating Ltd | Construction | 2022 |
| D Jackson Cycle Services Ltd | Manufacturing | 2022 |
| D K Skills & Development Limited | Professional & scientific | 2018 |
| D P O'Loughlin Associates Ltd | Information & communication | 2015 |
| D Parsons Engineering Ltd | Construction | 2019 |
| D R Jointing Ltd | Construction | 2016 |
| D Ragan Plumbing & Heating Services Limited | Construction | 2023 |
| D Whitehouse Ltd | Professional & scientific | 2016 |
| D&G Building Services Limited | Construction | 2025 |
| D&M Electrical Specialists Ltd | Construction | 2015 |
| D&S Radford Services Ltd | Wholesale & retail | 2023 |
| D&Tmee Safety Services Ltd | Professional & scientific | 2025 |
| D&V Trans Ltd | Transport & logistics | 2022 |
| D-Lab Orthotic Solutions Ltd | Manufacturing | 2025 |
| D-Zador Ltd | Construction | 2024 |
| D.A. Brooks Plant and Demolition Contractors Limited | Construction | 2001 |
| D.E. Mulligan Electrical Limited | Construction | 2025 |
| D.J.B. Industrial Products Limited | Wholesale & retail | 2002 |
| D.T.Stone Engineering Limited | Manufacturing | 2004 |
| DA Hallett Limited | Professional & scientific | 2015 |
| Dack & Burke Ltd | Construction | 2019 |
| Dacol Engineering Limited | Administrative & support | 2007 |
| Dactyl Publishing Limited | Information & communication | 2001 |
| DAD & LAD Bubbles Ltd | Administrative & support | 2019 |
| Dagmarsh Holdings Limited | Financial services | 2025 |
| Daily Fresh Swindon Limited | Wholesale & retail | 2009 |
| Daisy 1967 Limited | Extraterritorial | 2015 |
| Daisy Celebration Ltd | Hospitality | 2023 |
| Daisy Leaf Ltd | Information & communication | 2018 |
| Dakota Digital Ltd | Professional & scientific | 2011 |
| Dalby Motors Limited | Wholesale & retail | 2008 |
| Dale (Agencies) Limited | Extraterritorial | 2002 |
| Dales Furniture Matlock Limited | Manufacturing | 2002 |
| Dalestorth Property Ltd | Real estate | 2019 |
| Dalewares Limited | Hospitality | 2023 |
| Dalipaj Investments Ltd | Real estate | 2026 |
| Dallimzer Ltd | Wholesale & retail | 2022 |
| Dame Flogan Business Developments Limited | Manufacturing | 1982 |
| Dameon Electrical Ltd | Construction | 2014 |
| DAN P Electrical Ltd | Construction | 2025 |
| Danby Painting Contractors Ltd | Construction | 2004 |
| Dance@ the Works Ltd | Arts & recreation | 2016 |
| Dani Trans Ltd | Transport & logistics | 2026 |
| Daniel Katrycz Ltd | Transport & logistics | 2023 |
| Danti Sames Ltd | Wholesale & retail | 2025 |
| DAR Cafe Ltd | Hospitality | 2020 |
| Dara Trade Ltd | Transport & logistics | 2022 |
| Darach AI Limited | Information & communication | 2021 |
| Darby Associates Ltd | Professional & scientific | 2013 |
| Darby Healthcare Limited | Public administration | 2020 |
| Darcie Estates Ltd | Real estate | 2024 |
| Darecki Ltd | Administrative & support | 2021 |
| Dariantonia Limited | Transport & logistics | 2022 |
| Dariza Ltd | Wholesale & retail | 2020 |
| Dark Asylum Limited | Professional & scientific | 2019 |
| Dark Horse Equestrian Limited | Wholesale & retail | 2020 |
| Darling Solutions Limited | Information & communication | 2020 |
| Darren Bacon Engineering Solutions Ltd | Professional & scientific | 2026 |
| Darren Else Services Ltd | Wholesale & retail | 2024 |
| Darshan Atma Properties Limited | Real estate | 2024 |
| Dash - Delivering Activities Sports and Healthy Habits Ltd | Arts & recreation | 2025 |
| Dasmesh Limited | Real estate | 2008 |
| Davcom IT Limited | Information & communication | 2009 |
| Dave Allen Properties Ltd | Real estate | 2018 |
| Dave Goodwin Joinery Services Ltd | Construction | 2013 |
| Dave Jones Consulting Ltd | Professional & scientific | 2023 |
| Davenport Custom Coachwork Limited | Administrative & support | 2010 |
| Daves Independent MOT Test Centre Ltd | Administrative & support | 2003 |
| David Beaumont Development Ltd | Information & communication | 2012 |
| David Brett Ltd | Information & communication | 2025 |
| David Hayes Limited | Construction | 2018 |
| Davidson Building Services Limited | Construction | 2015 |
| Davis & Purdy Limited | Wholesale & retail | 2024 |
| Davison & Sons Ltd | Construction | 2024 |
| Dawn MK Limited | Hospitality | 2005 |
| Dawn Wheeler Crafts Limited | Arts & recreation | 2014 |
| Dawson's Property Ltd | Real estate | 2025 |