| Cosz Enterprise UK Limited | Manufacturing | 2019 |
| Coulthard Properties Limited | Real estate | 2025 |
| Country Kitchen JS Ltd | Hospitality | 2024 |
| Country Manor Retreats Ltd | Real estate | 2025 |
| Courage Creative Ltd | Arts & recreation | 2011 |
| Coursebox Limited | Education | 2021 |
| Courtney's Hair & Beauty NE Ltd | Other services | 2025 |
| CPB Electrical Services Ltd | Construction | 2024 |
| CPT Accountants Ltd | Professional & scientific | 2013 |
| CPT Business Consultants Ltd | Professional & scientific | 2016 |
| CPT Payroll Services Ltd | Administrative & support | 2016 |
| CPT Support Services Ltd | Professional & scientific | 2013 |
| CPT Tax Planning Ltd | Professional & scientific | 2016 |
| Craig's Timber Supplies(North East) Ltd | Wholesale & retail | 2022 |
| Crawford Cladding Solutions Ltd | Construction | 2023 |
| CRE8 Print & Sign Limited | Manufacturing | 2010 |
| Crispy COD Penshaw Limited | Hospitality | 2025 |
| Critical Risk Management Limited | Administrative & support | 2014 |
| Crownies Holdings Ltd | Real estate | 2024 |
| CRV Cars Ltd | Wholesale & retail | 2024 |
| Cryo Rentals Limited | Administrative & support | 2010 |
| Crystal Investment Holdings Limited | Financial services | 2014 |
| Csdp (UK) Ltd | Health & social care | 2010 |
| CSP Services Ltd | Other services | 2020 |
| Cummings and Pattison Limited | Construction | 2003 |
| Cumulate Ltd | Information & communication | 2016 |
| Current Electrical North East Limited | Construction | 2025 |
| CVF Psychology Ltd | Health & social care | 2022 |
| CWL Home Improvements Ltd | Construction | 2019 |
| Cybermoor Community Services Ltd | Information & communication | 2018 |
| Cygnet Sourcing Ltd | Administrative & support | 2023 |
| D & B Wise Properties Limited | Real estate | 2021 |
| D & C Collinson Limited | Hospitality | 2007 |
| D & K Transport Solutions Ltd | Administrative & support | 2025 |
| D J Hemmings Industrial Roofing & Cladding Ltd | Construction | 2022 |
| D Parsons Accountancy Ltd | Professional & scientific | 2014 |
| D&J Cars Ltd | Wholesale & retail | 2020 |
| D&M Recycling Ltd | Wholesale & retail | 2023 |
| D&S Property Lets Limited | Real estate | 2023 |
| D.K Pallet Services Ltd | Wholesale & retail | 2005 |
| D.S.J Access Ltd | Manufacturing | 2018 |
| D2 Publications Ltd | Information & communication | 2021 |
| Dairy Lane (ST. Michael's) Limited | Health & social care | 2013 |
| Dalk Services Limited | Professional & scientific | 2017 |
| Damsongreen Energyfarm Limited | Energy | 2024 |
| DAN Prince Productions Limited | Professional & scientific | 2013 |
| Danal Logistics Limited | Transport & logistics | 2021 |
| Daniel John Car Sales Ltd | Wholesale & retail | 2024 |
| Dannat Drywall Limited | Construction | 2002 |
| Danu II Holdings Limited | Administrative & support | 2008 |
| Darras Hall Bespoke Properties Ltd | Real estate | 2020 |
| Darren Youll Mortgage and Protection Consultant Ltd | Professional & scientific | 2022 |
| Dave Saul Limited | Information & communication | 2017 |
| David Baker Offshore Ltd | Mining & quarrying | 2026 |
| David Baxter Consultancy Limited | Professional & scientific | 2016 |
| Davidson's Kitchen Ltd | Hospitality | 2025 |
| Davison Blade Access Ltd | Other services | 2022 |
| Day & Night Property Services Limited | Construction | 2011 |
| DB Skip Hire Limited | Water & waste | 2025 |
| DB Tree & Garden Services Ltd | Administrative & support | 2026 |
| DC Inspection and Verification Services Ltd | Professional & scientific | 2018 |
| DE LA Casa Limited | Construction | 2009 |
| Debaze Ltd | Wholesale & retail | 2024 |
| Decom Limited | Construction | 2023 |
| Decom Offshore Limited | Construction | 2013 |
| Deltarad Limited | Health & social care | 2022 |
| Design Concepts (Northern) Limited | Professional & scientific | 2002 |
| Designer Cucina Ltd | Administrative & support | 2019 |
| Detailed 2 YOU Limited | Households | 2025 |
| DFI Films Limited | Information & communication | 2009 |
| DFI Properties Limited | Construction | 2014 |
| Dgps Partnership LLP | | 2013 |
| DGR Assessment Solutions Limited | Other services | 2009 |
| DGR Consultancy Services Ltd | Information & communication | 2016 |
| DGW (2005) Limited | Manufacturing | 2005 |
| DH Project Solutions Ltd | Construction | 2024 |
| DH5 Spice Junction Ltd | Hospitality | 2025 |
| Dhesi Holdings Limited | Real estate | 2017 |
| Dhesi Property 1 Limited | Real estate | 2017 |
| Dhesi Property 2 Limited | Real estate | 2017 |
| Dhesi Property 3 Limited | Real estate | 2017 |
| Dhesi Property 4 Limited | Real estate | 2018 |
| Dhesi Property 5 Limited | Real estate | 2019 |
| Dhpp Asset Management Limited | Real estate | 2022 |
| Dhqt Yummy Limited | Hospitality | 2025 |
| Digishop Ecommerce Limited | Wholesale & retail | 2013 |
| Dinky Solutions UK Ltd | Manufacturing | 2021 |
| Direct Global Group Limited | Financial services | 2024 |
| Distance Learning Courses Limited | Education | 2016 |
| DJH Resources Ltd | Health & social care | 2023 |
| DJL Capital Ltd | Financial services | 2022 |
| DM Property Solutions (NE) Limited | Construction | 2017 |
| DMC Newsplus Limited | Wholesale & retail | 1999 |
| DMK Cleaning Solutions Ltd | Wholesale & retail | 2024 |
| Doncaster Foot Clinic Ltd | Health & social care | 2020 |
| Dotty's Bar Limited | Hospitality | 2024 |
| DP Payroll Ltd | Professional & scientific | 2017 |
| DR Gracia Rose Aesthetics Ltd | Other services | 2022 |
| Dragonflies Ltd | Arts & recreation | 2016 |
| DRC Home&Business Ltd | Construction | 2025 |