| Custom Monkey Ltd | Wholesale & retail | 2018 |
| Custom Prefabricating Ltd | Manufacturing | 2026 |
| Customer First UK Limited | Other services | 2003 |
| Customer Hero Logistics Ltd | Transport & logistics | 2025 |
| Cusworth Croft Development Limited | Households | 2026 |
| Cusworth Education Services Limited | Education | 2012 |
| Cusworth Motor Company Doncaster Limited | Wholesale & retail | 2017 |
| Cusworth Motors Limited | Wholesale & retail | 2016 |
| Cutler IT Limited | Information & communication | 2010 |
| Cutting Edge Garden and Ground Maintenance Limited | Professional & scientific | 2022 |
| Cutting Edge Paving Limited | Construction | 2008 |
| CV TEC Ltd | Construction | 2021 |
| CVN Ltd | Construction | 2019 |
| CVS Truck Park Limited | Administrative & support | 2017 |
| CW Doncaster Investments Limited | Hospitality | 2026 |
| CW Roofing and Building Services Ltd | Construction | 2019 |
| Cwhf Property Limited | Real estate | 2026 |
| CWR Events Management Ltd | Administrative & support | 2024 |
| Cwss Ltd | Transport & logistics | 1998 |
| CWW Itconsulting Ltd | Information & communication | 2022 |
| Cybele Agency Ltd | Professional & scientific | 2020 |
| Cybershop Limited | Transport & logistics | 2007 |
| Cyberstar UK Limited | Real estate | 1997 |
| Cybrank Ltd | Financial services | 2025 |
| Cybraxo Ltd | Information & communication | 2024 |
| Cycene Investments Limited | Manufacturing | 2017 |
| Cycene Limited | Manufacturing | 2011 |
| Cygneture Bars Ltd | Wholesale & retail | 2024 |
| Cyml (Holdings) Limited | Financial services | 2025 |
| CZ -Design &Production Limited | Construction | 2024 |
| D & a Logistics Ltd | Transport & logistics | 2025 |
| D & C Cleaners Ltd | Administrative & support | 2025 |
| D & D Mining Limited | | 2014 |
| D & F Mccallum Ltd | Agriculture & fishing | 2014 |
| D & G Enterprises Limited | Professional & scientific | 2015 |
| D & G Investments Limited | Real estate | 2011 |
| D & G Plastic Fabrications Ltd | Manufacturing | 2009 |
| D & H Bates Estates Ltd | Real estate | 2020 |
| D & J Aloe Products Limited | Wholesale & retail | 2014 |
| D & L Bubble Packaging Ltd | Administrative & support | 2017 |
| D & M Body & Paint Ltd | Wholesale & retail | 2025 |
| D & P Consultancy Ltd | Information & communication | 2012 |
| D & SB Properties Ltd | Real estate | 2026 |
| D and P Fabrications Ltd | Manufacturing | 2022 |
| D Appleyard Welding Services Ltd | Manufacturing | 2014 |
| D Automotive Ltd | Wholesale & retail | 2026 |
| D B Drainage Ltd | Construction | 2006 |
| D Beniston Transport Ltd | Transport & logistics | 2016 |
| D Bennett Jewellers Limited | Wholesale & retail | 2006 |
| D Birkby Joinery Ltd | Construction | 2023 |
| D C Cook Autos Ltd | Wholesale & retail | 2025 |
| D C Properties (Doncaster) Ltd | Real estate | 2023 |
| D G Howard Ltd | Construction | 2003 |
| D Glover Limited | Construction | 2008 |
| D Groceries Limited | Wholesale & retail | 2023 |
| D H Langley and Company Limited | Wholesale & retail | 2004 |
| D Holbrey Limited | Construction | 2015 |
| D Hub Systems Ltd | Information & communication | 2024 |
| D Hughes Well Drillers Limited | Construction | 2008 |
| D J Brindley Holdings Ltd | Financial services | 2025 |
| D Jani Construction Ltd | Construction | 2019 |
| D Kelbie Truck & Machinery Sales Ltd | Wholesale & retail | 2011 |
| D Knowles Parks & Properties Ltd | Real estate | 2021 |
| D L J Electrical Contractors Ltd | Construction | 2020 |
| D L J Property Developments Limited | Real estate | 2024 |
| D M Square Ltd | Transport & logistics | 2019 |
| D Marshall Investments Limited | Administrative & support | 2019 |
| D Mould & Sons(Plastering Contractors) Limited | Construction | 2007 |
| D N Harvey Electrical Ltd | Construction | 2023 |
| D Noble Consultancy Ltd | Professional & scientific | 2021 |
| D Plus 3 Ltd | Administrative & support | 2020 |
| D R Howell Consultancy Ltd | Professional & scientific | 2024 |
| D S Logistics Ltd | Transport & logistics | 2018 |
| D S Realtors Limited | Real estate | 2025 |
| D S W Management Limited | Administrative & support | 2014 |
| D Swallow Builders Ltd | Construction | 2024 |
| D Tech Elevators Ltd | Manufacturing | 2018 |
| D&C Facilities Management Limited | Construction | 2015 |
| D&D Logistics 2018 Ltd | Transport & logistics | 2018 |
| D&D Rentals Ltd | Households | 2017 |
| D&D Trans Services Ltd | Transport & logistics | 2024 |
| D&D&A Ltd | Transport & logistics | 2025 |
| D&Gr Services Ltd | Professional & scientific | 2022 |
| D&H Building Services Ltd | Construction | 2022 |
| D&H One Ltd | Manufacturing | 2019 |
| D&J Plasterers Ltd | Construction | 2018 |
| D&Jp Investments Limited | Real estate | 2024 |
| D&K Properties Ltd | Households | 2026 |
| D&L Property & Developments Ltd | Construction | 2025 |
| D&L Spedition Ltd | Transport & logistics | 2021 |
| D&M Baines Ltd | Real estate | 2021 |
| D&M Bridge Estates Holding Limited | Financial services | 2025 |
| D&P Logistics Ltd | Transport & logistics | 2024 |
| D&R Insulations Services Limited | Construction | 2010 |
| D. & S. (Household Goods) Limited | Wholesale & retail | 1976 |
| D. Jackson Slurry Seal Ltd | Construction | 2023 |
| D. Marshall Contract Services Ltd | Transport & logistics | 2018 |
| D. Simcock & SON Limited | Construction | 2015 |
| D. Wilcock Properties Limited | Real estate | 2020 |
| D.A.L.E.S. Utilities Civils and Plant Limited | Administrative & support | 2015 |