| Crossdale Services Ltd | Administrative & support | 2020 |
| Croton Escapes Ltd | Hospitality | 2026 |
| Croton Estates Ltd | Real estate | 2025 |
| Crown Roofing and Building Ltd | Construction | 2025 |
| Crown Star Homes Ltd | Real estate | 2025 |
| Crownworth Logistics Limited | Transport & logistics | 2026 |
| Crozu Transport Ltd | Transport & logistics | 2024 |
| CRS Hair Ltd | Other services | 2025 |
| Crumb & Co Bakehouse Ltd | Wholesale & retail | 2025 |
| Crystal Auto Care Ltd | Administrative & support | 2026 |
| Crystal Medics Limited | Health & social care | 2016 |
| Crystal Property Management Group Ltd | Real estate | 2023 |
| Crystalvale Ltd | Health & social care | 2025 |
| CS Highways & Consultancy Ltd | Professional & scientific | 2024 |
| CS2 Management LLP | | 2006 |
| CSC Buildings Ltd | Construction | 2009 |
| CSD Pods Ltd | Professional & scientific | 2026 |
| Cses Consultancy Ltd | Professional & scientific | 2023 |
| CSF Software Limited | Information & communication | 2011 |
| CSG Engineering Ltd | Professional & scientific | 2025 |
| CT Cosy Homes Ltd | Real estate | 2025 |
| CTA Completions Ltd | Professional & scientific | 2025 |
| CTB Lofts & Construction Ltd | Construction | 2026 |
| Cubik Surance Ltd | Professional & scientific | 2023 |
| Cuda Medics Limited | Health & social care | 2024 |
| Cufi Construction Ltd | Construction | 2018 |
| Curated Conservation Ltd | Professional & scientific | 2022 |
| Curative Music Foundation Ltd | Professional & scientific | 2012 |
| Custom Hydro Limited | Manufacturing | 2021 |
| Customs X Ltd | Administrative & support | 2020 |
| CV Property Management Limited | Real estate | 2012 |
| CV Surgical Services Ltd | Professional & scientific | 2018 |
| CW Drylining Ltd | Construction | 2018 |
| CWC Consultancy Limited | Professional & scientific | 2019 |
| CY Abbott Amusements Limited | Arts & recreation | 2024 |
| Cybarik Limited | Information & communication | 2022 |
| Cyberconnect Limited | Information & communication | 2015 |
| Cyberloop Systems Limited | Information & communication | 2016 |
| Cyberpride Solutions Ltd | Information & communication | 2024 |
| Cybr Solutions Limited | Administrative & support | 2026 |
| Cylo Labs Ltd | Information & communication | 2024 |
| Cylo Ltd | Information & communication | 2010 |
| Cyntra MED Consulting Ltd | Health & social care | 2024 |
| Cyprus Selective Logistics Ltd | Wholesale & retail | 2021 |
| Cyril Transport Ltd | Transport & logistics | 2018 |
| Cyson Properties Ltd | Real estate | 2025 |
| Cystomed Ltd | Extraterritorial | 2015 |
| D & B Scaffolding (Design) Limited | Professional & scientific | 2021 |
| D & B Scaffolding (Northern) Limited | Construction | 2018 |
| D & B Scaffolding Holdings Ltd | Financial services | 2016 |
| D a Jones UK Logistics Ltd | Transport & logistics | 2022 |
| D and D Glassworks Ltd | Construction | 2025 |
| D Angell Couriers Limited | Transport & logistics | 2016 |
| D Clim Ltd | Transport & logistics | 2019 |
| D Elliott Flooring Limited | Construction | 2018 |
| D F F Rendering Solutions Ltd | Construction | 2019 |
| D Mihai Limited | Information & communication | 2016 |
| D P Lawless Painting & Decorating Services Limited | Construction | 2003 |
| D Plumbing&Heating Expert Ltd | Construction | 2023 |
| D West Services Ltd | Other services | 2022 |
| D Wrench Driver Services Ltd | Other services | 2014 |
| D&A Artisanal Sweets Limited | Manufacturing | 2026 |
| D&C Equestrian Ltd | Agriculture & fishing | 2026 |
| D&D General Building Ltd | Construction | 2020 |
| D&D Invest Property Ltd | Real estate | 2025 |
| D&H Housing Limited | Real estate | 2022 |
| D&K Motors London Limited | Wholesale & retail | 2013 |
| D&M Shepherd Limited | Real estate | 2024 |
| D&S Property Lettings Ltd | Real estate | 2025 |
| D&S Top Services Ltd | Construction | 2015 |
| D&Zin Ltd | Transport & logistics | 2021 |
| D-Smart Catering Ltd | Hospitality | 2019 |
| D. Kazakov Limited | Transport & logistics | 2012 |
| D.H. Plumbing & Heating Services Limited | Construction | 2018 |
| D.I.Y Driving School Ltd | Wholesale & retail | 2025 |
| D.Paesano Props Ltd | Information & communication | 2019 |
| D.T Polishing Ltd | Wholesale & retail | 2025 |
| D.T.W. Engines Limited | Wholesale & retail | 1980 |
| D1 Scaffolding Limited | Construction | 2013 |
| D3 Creative Limited | Professional & scientific | 1998 |
| D3 Group Limited | Extraterritorial | 2000 |
| D3 Holdings Limited | Professional & scientific | 2006 |
| D3 Sign Systems Ltd | Professional & scientific | 2012 |
| D3 Standard Ltd | Wholesale & retail | 2025 |
| D4TF Ltd | Wholesale & retail | 2024 |
| D74UV Ltd | Professional & scientific | 2024 |
| DA & DA Medical Ltd | Health & social care | 2024 |
| DA BA Properties Ltd | Real estate | 2023 |
| DA GAS Heating & Plumbing Ltd | Construction | 2017 |
| Daarstone Limited | Real estate | 2026 |
| DAB Supply Limited | Wholesale & retail | 2025 |
| Dabbs Educational Limited | Education | 2017 |
| Dacres Gate Management Limited | Households | 2003 |
| Dada’S Skin Limited | Health & social care | 2024 |
| Dadora Care Ltd | Health & social care | 2025 |
| DAF Environmental Ltd | Transport & logistics | 2017 |
| Daf-Hc Ltd | Health & social care | 2022 |
| Daff's Spring Clean Ltd | Administrative & support | 2025 |
| Dairak Finishing Ltd | Construction | 2020 |
| Daisy Florist Limited | Wholesale & retail | 2023 |