| CS Traffic Management Ltd | Construction | 2023 |
| CS Transport (Yorkshire) Limited | Transport & logistics | 2022 |
| CS21 Ltd | Health & social care | 2020 |
| Cscl Limited | Professional & scientific | 2020 |
| Cscs Business Services Limited | Construction | 2018 |
| Cscy Holdings Ltd | Real estate | 2024 |
| Csdb Consulting Limited | Professional & scientific | 2017 |
| CSI Building Services Ltd | Construction | 2020 |
| CSK Motors Ltd | Wholesale & retail | 2014 |
| CSL Collective Solutions Ltd | Agriculture & fishing | 2025 |
| CSR Electrical Services Limited | Construction | 2018 |
| CSR Service Station Ltd | Wholesale & retail | 2023 |
| CSS Bramley Ltd | Hospitality | 2024 |
| CT Brands (UK) Limited | Wholesale & retail | 2021 |
| CT Nova (UK) Limited | Wholesale & retail | 2020 |
| CTC Payroll Services Limited | Professional & scientific | 2011 |
| CTE Property Investments Limited | Real estate | 2021 |
| Ctjm Developments Limited | Construction | 2014 |
| Ctjt Ltd | Hospitality | 2025 |
| CTL Engineering Ltd | Professional & scientific | 2025 |
| Ctlm Limited | Professional & scientific | 2022 |
| CTS PC Solutions Limited | Other services | 2010 |
| Ctshuma Ltd | Health & social care | 2023 |
| Cttraders Ltd | Wholesale & retail | 2020 |
| Cuban Enterprises Limited | Professional & scientific | 2007 |
| Cubisnap Ltd | Information & communication | 2025 |
| Culcrae Limited | Agriculture & fishing | 1997 |
| Cumberland Consulting (York) Ltd | Information & communication | 2022 |
| Cumulus Energy Storage Limited | Manufacturing | 2012 |
| Cuneo Coupe Construction Limited | Manufacturing | 2023 |
| Cuppa N Cake Limited | Hospitality | 2019 |
| Curator GEZ Ltd | Financial services | 2026 |
| Curator MTD Ltd | Information & communication | 2026 |
| Curator Ryan Ltd | Financial services | 2026 |
| Curator TIM Ltd | Financial services | 2026 |
| Curious World Limited | Arts & recreation | 2022 |
| Curitex Ltd | Wholesale & retail | 2025 |
| Curryleafs Foods Ltd | Hospitality | 2025 |
| Cushty Cushty Competition's Limited | Arts & recreation | 2025 |
| Custom Asset Finance Ltd | Financial services | 2016 |
| Custom BF Services Ltd | Financial services | 2018 |
| Custom Business Finance Ltd | Financial services | 2016 |
| Cusworth Occupational Health Limited | Health & social care | 2025 |
| CUT Price Kimbo Ltd | Wholesale & retail | 2026 |
| CUT to the Chase Consulting Limited | Professional & scientific | 2010 |
| CUT Wheels Ltd | Wholesale & retail | 2021 |
| Cutacre Country Park Management Company Limited | Households | 2019 |
| Cutler Communications Group Limited | Financial services | 2017 |
| Cutler Communications Holdings Limited | Professional & scientific | 2012 |
| Cutler Communications Solutions Limited | Information & communication | 2002 |
| Cutler SYH Ltd | Financial services | 2023 |
| Cutthroats Barbershop Limited | Other services | 2019 |
| Cutting Room (the Salon) Ltd | Other services | 2011 |
| CVC Consultancy Ltd | Professional & scientific | 2017 |
| CW Joinery and Property Solutions Limited | Construction | 2025 |
| CW Tank Installations Limited | Construction | 2024 |
| CX01 Ltd | Real estate | 2020 |
| Cxxc Transport Ltd | Transport & logistics | 2025 |
| CY Ocean City Limited | Hospitality | 2025 |
| Cyber Alchemy Limited | Information & communication | 2022 |
| Cyber Spider Ltd | Information & communication | 2017 |
| Cyberate Global Ltd | Information & communication | 2022 |
| Cybershift Limited | Extraterritorial | 1998 |
| Cyclotron Specialists Ltd | Health & social care | 2019 |
| Cyril Cooper & Sons Limited | Agriculture & fishing | 1964 |
| CZS Property Ltd | Construction | 2025 |
| D & a Investments Partnership Limited | Professional & scientific | 2016 |
| D & a Partnership Limited | Professional & scientific | 2013 |
| D & G Pipeline Contracting Limited | Construction | 2012 |
| D & G Utilities Limited | Construction | 2011 |
| D & G Water Infrastructure Limited | Construction | 2020 |
| D & L Limited | Construction | 1997 |
| D & R Autokraft Suppliers Ltd | Wholesale & retail | 2010 |
| D & T Dairy Limited | Wholesale & retail | 2011 |
| D and E Wholesale Ltd | Wholesale & retail | 2018 |
| D Birkett Interiors Ltd | Administrative & support | 2017 |
| D Briggs Properties Ltd | Real estate | 2025 |
| D Caswell Services Ltd | Construction | 2015 |
| D Challinor Kitchen Installations Limited | Construction | 2015 |
| D Charlton Transport Ltd | Transport & logistics | 2025 |
| D Downs Interiors Ltd | Construction | 2026 |
| D Everton Plastering Limited | Construction | 2015 |
| D G & B Holdings Limited | Financial services | 2020 |
| D H Automation Ltd | Professional & scientific | 2025 |
| D H Trade Cars Ltd | Wholesale & retail | 2020 |
| D J Building & Developments Ltd | Real estate | 2018 |
| D J Close & Sons Ltd | Construction | 2010 |
| D Johnson Brickwork Ltd | Construction | 2023 |
| D K W Brickwork Limited | Construction | 2023 |
| D Lewis Paving Limited | Administrative & support | 2016 |
| D P Fast Transport Ltd | Transport & logistics | 2025 |
| D R Plastering Yorkshire Ltd | Construction | 2023 |
| D Rose Green Technologies Ltd | Construction | 2021 |
| D S Motors (UK) Ltd | Wholesale & retail | 2010 |
| D Smith Engineering Services Limited | Manufacturing | 2015 |
| D&B Light Ltd | Administrative & support | 2017 |
| D&L Clothing Sales Ltd | Wholesale & retail | 2026 |
| D&M Service Provider Ltd | Hospitality | 2019 |
| D&R Tyres (SY) Limited | Wholesale & retail | 2017 |
| D'N'A Building & Roofing Limited | Construction | 2015 |