| Curt Taylor Film Ltd | Administrative & support | 2022 |
| Curzon Estate Management Ltd | Real estate | 2022 |
| Customcreationsuk Ltd | Manufacturing | 2026 |
| CUT Away Films Limited | Other services | 2016 |
| Cutting Edge Gardens Limited | Administrative & support | 2022 |
| Cutting Hill Clinic LLP | | 2016 |
| Cuzons Developments Limited | Real estate | 2018 |
| Cuzons Holdings Limited | Real estate | 2017 |
| CWG Contracts Ltd | Construction | 2018 |
| CWH Supplements Limited | Wholesale & retail | 2022 |
| Cybourn Limited | Information & communication | 2019 |
| Cygnus Healthcare Ltd | Health & social care | 2019 |
| Cypt Medical Services Ltd | Health & social care | 2024 |
| Cyrex Studios Limited | Information & communication | 2023 |
| Cyro Cyber Ltd | Information & communication | 2021 |
| Cyscore Limited | Information & communication | 2022 |
| D & B Rosey Ltd | Health & social care | 2013 |
| D & B TS Limited | Information & communication | 1981 |
| D & C Kitchen Installations Ltd | Construction | 2016 |
| D & D Prop 1 Ltd | Real estate | 2024 |
| D Bradley and Sons Ltd | Construction | 2021 |
| D Britton Carpentry Limited | Construction | 2023 |
| D C Heating Systems Ltd | Construction | 2022 |
| D C Rigging Services Ltd | Construction | 2017 |
| D G Maintenance Services Limited | Construction | 1999 |
| D Herdman Brickwork Ltd | Construction | 2018 |
| D M Harley Construction Limited | Construction | 2018 |
| D N Healthcare Ltd | Health & social care | 2023 |
| D Nash Properties Limited | Real estate | 2024 |
| D Selby Brickwork Limited | Construction | 2023 |
| D Seymour & Hynd Ltd | Wholesale & retail | 2019 |
| D V Stevenage Ltd | Hospitality | 2018 |
| D& M Logistics (UK) Limited | Construction | 2006 |
| D&I Medical Ltd | Health & social care | 2020 |
| D.A. Freeman Ltd | Real estate | 2015 |
| D.A.O Care for Living Limited | Public administration | 2024 |
| D.Aura Events and Decor Ltd | Hospitality | 2026 |
| D.L.R Logistics Limited | Transport & logistics | 2022 |
| D.Northfield Holdings Ltd | Financial services | 2023 |
| D.R. Accountancy Services Limited | Professional & scientific | 2007 |
| D.Sibley Limited | Health & social care | 2025 |
| D1 Security UK Limited | Administrative & support | 2022 |
| D3NTAL Powerhouse Partnership Ltd | Professional & scientific | 2019 |
| DA Moore Ltd | Health & social care | 2021 |
| Dabuco Ltd | Professional & scientific | 2024 |
| Daffodil Acctax UK Ltd | Professional & scientific | 2012 |
| Dahliakay Limited | Health & social care | 2019 |
| Daimca Clira Ltd | Wholesale & retail | 2021 |
| Daisychain Properties Limited | Real estate | 2011 |
| DAK 1985 Ltd | Administrative & support | 2018 |
| Dally Solution Ltd | Health & social care | 2014 |
| Damore Financial Solutions Limited | Professional & scientific | 2025 |
| Damson Duck Ltd | Manufacturing | 2022 |
| Damtamy Limited | Health & social care | 2013 |
| DAN Barnard Media Ltd | Information & communication | 2020 |
| DAN Drysdale Limited | Information & communication | 2012 |
| DAN Gibling Ltd | Information & communication | 2014 |
| DAN Knight Films Ltd | Information & communication | 2015 |
| Dananoah Ltd | Health & social care | 2015 |
| Danht Property Management Limited | Real estate | 2026 |
| Dani's Styles Ltd | Other services | 2012 |
| Dania Limited | Construction | 2011 |
| Daniel Gill Transport Limited | Transport & logistics | 2017 |
| Daniel Knight Music Limited | Information & communication | 2012 |
| Daniel Lewis Construction Ltd | Construction | 2017 |
| Danmar Design Ltd | Construction | 2010 |
| Danmart 24 Ltd | Construction | 2024 |
| Danube Education Services UK Limited | Education | 2023 |
| Dapa Solutions Ltd | Information & communication | 2014 |
| Dapper Fashions Limited | Real estate | 2013 |
| Dapper Togs Limited | Wholesale & retail | 2017 |
| Darex Business Solutions Limited | Professional & scientific | 2014 |
| Daring Consulting Limited | Professional & scientific | 2019 |
| Daripp Healthcare Services Limited | Administrative & support | 2018 |
| Darker Professional Services Limited | Professional & scientific | 2015 |
| Darling GEM Designs Ltd | Arts & recreation | 2024 |
| Darren Carter Properties Ltd | Real estate | 2022 |
| Darren's Engineering Company Ltd | Professional & scientific | 2021 |
| Dartkite Limited | Other services | 2020 |
| Dartmouth House Catherine Grove Residents Association Limited | Real estate | 1997 |
| DAS4 Services Ltd | Administrative & support | 2025 |
| Dasad Limited | Financial services | 2017 |
| Dash Studios Limited | Financial services | 2014 |
| Dash-In Ltd | Hospitality | 2011 |
| Data Integrator Ltd | Other services | 2023 |
| Data Pyxis Limited | Professional & scientific | 2015 |
| Datacats Ltd | Information & communication | 2016 |
| Datacenex Limited | Administrative & support | 2013 |
| Dataday Contracts Limited | Information & communication | 2006 |
| Datchworth Services Ltd | Administrative & support | 2025 |
| Datum Technical Services Ltd | Arts & recreation | 2025 |
| Dauntless Home Ltd | Real estate | 2023 |
| Davcaz Limited | Transport & logistics | 2014 |
| Dave Lawson Limited | Information & communication | 2014 |
| David Barney & Company LLP | | 2024 |
| David Cullimore Photography Limited | Professional & scientific | 2022 |
| David Grahame Ltd | Other services | 2022 |
| David Handy Carpentry Services Ltd | Construction | 2021 |
| David James Contract Cleaning Limited | Administrative & support | 2025 |
| David Lodge Lighting Ltd | Professional & scientific | 2016 |