| CSG Agricultural Limited | Water & waste | 2019 |
| CSL Promotions Limited | Construction | 2023 |
| CSL Strategic Limited | Administrative & support | 2020 |
| Cslgr Limited | Real estate | 2020 |
| CT Group Limited | Manufacturing | 2006 |
| CTH Cleaning Services Ltd | Administrative & support | 2019 |
| CTS Developments Limited | Construction | 2007 |
| CTS Systems (Southern) LLP | | 2007 |
| CTS Systems (UK) Ltd. | Professional & scientific | 2006 |
| Cube Transport Ltd | Transport & logistics | 2025 |
| Cubik Capital Limited | Financial services | 2023 |
| CUE Star Academy Ltd | Arts & recreation | 2025 |
| Cuelight Media Limited | Information & communication | 2020 |
| Cuilcagh Contractors Ltd | Construction | 2019 |
| CUL DE SAC Limited | Real estate | 2018 |
| Cullinan Construction Consultants Ltd | Professional & scientific | 2022 |
| Cullinan Design Consultants Ltd | Professional & scientific | 2024 |
| Cullinan Wealth Limited | Construction | 2020 |
| Culminate Ltd | Administrative & support | 2012 |
| Cult Movie Shop Limited | Wholesale & retail | 2018 |
| Cultures Entwined C.I.C. | Health & social care | 2022 |
| Cunney Construction Midlands Ltd | Construction | 2023 |
| Cura Software Limited | Information & communication | 2025 |
| Curious Pencil Ltd | Wholesale & retail | 2015 |
| Currentworx Ltd | Construction | 2025 |
| Currier & Sons Limited | Wholesale & retail | 2019 |
| Curtco Ltd | Real estate | 2021 |
| Curtis D Limited | Other services | 2012 |
| Curtis Davies Media Limited | Administrative & support | 2009 |
| Curve Shop Limited | Wholesale & retail | 2010 |
| Curzon 3000 Limited | Construction | 2024 |
| Curzon Manor Investments Limited | Hospitality | 1974 |
| Custodian Group Ltd | Real estate | 2019 |
| Custodian Supported Housing CIC | Hospitality | 2020 |
| Custom Land Limited | Professional & scientific | 2014 |
| Custom Land Management Limited | Professional & scientific | 2017 |
| Customer Experience Consulting Ltd | Professional & scientific | 2021 |
| CUT Make & Trem Limited | Wholesale & retail | 2018 |
| CUT to the Jase Ltd | Professional & scientific | 2021 |
| CV Europe | Information & communication | 2019 |
| CV4RESIDENTIAL Limited | Real estate | 2026 |
| CVC Asia Limited | Information & communication | 1996 |
| Cvjh Holdings Ltd | Real estate | 2025 |
| Cvjh Solutions Ltd | Information & communication | 2024 |
| CVK Flooring Ltd | Construction | 2022 |
| Cwph (London) Limited | Real estate | 2011 |
| Cwph Limited | Real estate | 2010 |
| Cwph Trent Bridge Phase 2 Limited | Real estate | 2005 |
| Cyber Breach Solutions Ltd | Information & communication | 2021 |
| Cyber OT Security Ltd | Information & communication | 2014 |
| Cyberfare Limited | Information & communication | 2025 |
| Cybertech Data & Compliance Limited | Information & communication | 2024 |
| Cyberyard Limited | Information & communication | 2024 |
| Cygnus Atratus (UK) Ltd | Financial services | 2013 |
| Cygnus Creative Limited | Information & communication | 2013 |
| Cypher Travel Software Ltd | Administrative & support | 2024 |
| Cyridium Ltd | Financial services | 2019 |
| CZ Consulting Ltd | Professional & scientific | 2026 |
| Czech and Slovak Community UK C.I.C. | Education | 2026 |
| CZN Burak Xpress Birmingham Ltd | Hospitality | 2026 |
| D & D Stockley Mill Limited | Construction | 2018 |
| D & E Logistic Solutions Ltd | Transport & logistics | 2017 |
| D & G Landscaping Services Ltd | Administrative & support | 2026 |
| D & H Footings and Brickwork Ltd | Construction | 2017 |
| D & N Xpress Ltd | Transport & logistics | 2017 |
| D & R Accountancy Services Ltd | Professional & scientific | 2016 |
| D & R Group Investments Ltd | Real estate | 2020 |
| D & S (Electrical Services) Limited | Construction | 2017 |
| D & S Taverns Ltd | Other services | 2015 |
| D 8 V E W Sales and Marketing Limited | Other services | 2016 |
| D a Contracting Ltd | Construction | 2024 |
| D Christian GAS, Heating & Plumbing Ltd | Construction | 2025 |
| D Cookson Rigger Fitter Ltd | Construction | 2019 |
| D H G Contracts Ltd | Construction | 2017 |
| D H Joinery Limited | Manufacturing | 2003 |
| D Hayes Services Ltd | Professional & scientific | 2024 |
| D Hegarty Solutions Ltd | Construction | 2019 |
| D J Allcott Consultants Limited | Professional & scientific | 2022 |
| D J Hammond Electrical Contractors Limited | Construction | 2005 |
| D J P Enterprises Limited | Hospitality | 2010 |
| D K Bedi Solutions Limited | Information & communication | 2016 |
| D K CAD Services Limited | Construction | 2004 |
| D L Miles Consulting Limited | Information & communication | 2021 |
| D Malynn Technical Services Limited | Professional & scientific | 2014 |
| D Mockble Construction Ltd | Construction | 2025 |
| D P Building & Construction Limited | Construction | 2019 |
| D Roberts & SON Limited | Other services | 2002 |
| D Walsh Durham Ltd | Administrative & support | 2017 |
| D&A Future Investment Ltd | Real estate | 2025 |
| D&D Electrical Sales and Services Limited | Manufacturing | 2015 |
| D&H Nails Spa Ltd | Other services | 2024 |
| D&M Digital Limited | Information & communication | 2014 |
| D&M Services (Midlands) Ltd | Construction | 2007 |
| D&T Chilled Foods Limited | Wholesale & retail | 2017 |
| D-Mac Contracts Limited | Construction | 2015 |
| D. a. Mander & SON Ltd | Wholesale & retail | 2003 |
| D. Biddleston Limited | Construction | 2005 |
| D. England Engineering Ltd | Professional & scientific | 2016 |
| D. Jacques Plumbing & Heating Limited | Construction | 1985 |
| D. Mcgovern Ground Works Ltd | Construction | 2021 |