| Cullen's Cleaning Services Limited | Administrative & support | 2025 |
| Cullis Engineering Services Limited | Administrative & support | 2003 |
| Cullis Holdings Ltd | Real estate | 2017 |
| Cullis Pension Nominees Limited | Households | 2014 |
| Cuppie Limited | Real estate | 2020 |
| Curaden (UK) Limited | Health & social care | 2002 |
| Curatorlink Limited | Professional & scientific | 2026 |
| Curry HUT (Hunts) Ltd | Hospitality | 2023 |
| Curtis Roofing&Building Ltd | Construction | 2025 |
| Custom Removals Limited | Transport & logistics | 2019 |
| CUT Price Tiles & Bathrooms LLP | | 2004 |
| CUT Price Tiles Limited | Wholesale & retail | 1998 |
| Cutting Edge Custom Interiors Limited | Construction | 2011 |
| Cuzmik Holdings Ltd | Households | 2024 |
| Cwrp Relocation Limited | Construction | 2019 |
| Cyber & IT Risk Management Limited | Information & communication | 2016 |
| Cyber Caddy Ltd | Information & communication | 2025 |
| Cyclic Diagnostics Ltd | Health & social care | 2023 |
| Cydaura Limited | Information & communication | 2025 |
| Cyrus Audio Limited | Manufacturing | 2004 |
| D & K Seal Contractors Limited | Construction | 2011 |
| D & K Studios Limited | Wholesale & retail | 2005 |
| D a Payne Coach Hire Ltd | Transport & logistics | 2012 |
| D Abblitt & SON Ltd | Agriculture & fishing | 2011 |
| D and N Marquees and Events Ltd | Construction | 2022 |
| D B (Storage Containers) Limited | Real estate | 2022 |
| D E C Autos Limited | Wholesale & retail | 2014 |
| D K Racing Ltd | Administrative & support | 2017 |
| D M Electrical Services Limited | Construction | 1997 |
| D S Plumbing & Heating (Cambs) Limited | Construction | 2014 |
| D T Scenery Ltd | Information & communication | 2019 |
| D W German Car Transport Limited | Transport & logistics | 2002 |
| D&A Creative Limited | Professional & scientific | 2014 |
| D&E Paine Limited | Other services | 2019 |
| D&G Plus Care Ltd | Administrative & support | 2018 |
| D&T Utilities Ltd | Construction | 2023 |
| D. Davey & Sons Limited | Real estate | 1965 |
| D.L.N.Rentals Ltd | Transport & logistics | 2019 |
| D.N Network Services Ltd | Information & communication | 2019 |
| D.P Clarke & SON Limited | Construction | 2010 |
| DA Decoder Ltd | Information & communication | 2025 |
| DA Guia Ltd | Hospitality | 2019 |
| DA Vinci's Huntingdon Limited | Hospitality | 2020 |
| Dabby Ltd | Professional & scientific | 2016 |
| Dabro Holdings Ltd | Financial services | 2026 |
| Daisies Nursery School Limited | Education | 2015 |
| Daisypop 2025 Limited | Professional & scientific | 2025 |
| Dale Family Enterprises Ltd | Extraterritorial | 2026 |
| Dales Solutions Limited | Professional & scientific | 2019 |
| Daley Soccer Training Academy Ltd | Education | 2019 |
| Dale’S Home Rentals Ltd | Real estate | 2025 |
| Dalord Healthcare Limited | Health & social care | 2023 |
| Dalriada International Consulting Ltd | Other services | 2020 |
| Daly's Tea Ltd | Hospitality | 2017 |
| Damian Baron Ltd | Transport & logistics | 2016 |
| Damros Ltd | Wholesale & retail | 2026 |
| Dams Consultancy Limited | Professional & scientific | 2019 |
| Danlazar PDR Limited | Wholesale & retail | 2026 |
| Danna Training Ltd | Education | 2025 |
| Danny Spedition Limited | Transport & logistics | 2010 |
| Dans Driving Academy Ltd | Education | 2025 |
| Daphne Ford Ltd | Information & communication | 2022 |
| Dar-Bart Ltd | Transport & logistics | 2025 |
| Darjeeling Curry Limited | Hospitality | 2024 |
| Darjeeling Services Limited | Hospitality | 2018 |
| Darlow Exterior Cleaning Ltd | Administrative & support | 2024 |
| Darren Edwards Construction and Maintenance Limited | Administrative & support | 2018 |
| Darvi Solutions Ltd | Wholesale & retail | 2019 |
| Darwin Magdalene Property Limited | Construction | 2022 |
| Daryl Potter Services Limited | Transport & logistics | 2014 |
| Data Global Infrastructure Ltd | Manufacturing | 2025 |
| Data Housing Limited | Real estate | 2026 |
| Data Unbound Ltd | Information & communication | 2013 |
| Datafeast Ltd | Information & communication | 2020 |
| Datawoo Ltd | Professional & scientific | 2024 |
| Dave Holbrow Installations Ltd | Manufacturing | 2014 |
| Dave Industries Ltd | Manufacturing | 2018 |
| Davenport Trading Co Ltd | Wholesale & retail | 2020 |
| David Hamilton Landscape Design Limited | Professional & scientific | 2023 |
| David J Richards Limited | Manufacturing | 2003 |
| David Jeffreys Financial Services Ltd | Professional & scientific | 2012 |
| David Lockhart Agricultural Machinery Limited | Agriculture & fishing | 2014 |
| David Mccarthy Limited | Professional & scientific | 2011 |
| David Pickin Limited | Professional & scientific | 2015 |
| David Pope Consulting Limited | Professional & scientific | 2026 |
| David William Hyde Limited | Other services | 2010 |
| Davies Family Estates Ltd | Construction | 2020 |
| Davis Business Solutions Limited | Information & communication | 2025 |
| Dawson Plant Hire Limited | Real estate | 1975 |
| Day 1 Consulting Ltd | Information & communication | 2015 |
| Day Consulting Ltd | Professional & scientific | 2013 |
| Day Today Limited | Other services | 2010 |
| Daynamic Engineering Ltd | Wholesale & retail | 2023 |
| Dayonedone Ltd | Wholesale & retail | 2025 |
| DBM Developments TA DBM Landscapes Ltd | Administrative & support | 2013 |
| DBM Engineering Solutions Limited | Professional & scientific | 2013 |
| DBM Garden Maintenance Limited | Administrative & support | 2015 |
| DC L&D Ltd | Professional & scientific | 2022 |
| DC Logik Ltd | Manufacturing | 2013 |
| DC Streetlighting Services Ltd | Construction | 2026 |