| Coronation Indian Restaurant Ltd | Hospitality | 2018 |
| Corporate Staff Benefits Partnership LP | | 2010 |
| Cosco Construction Management Limited | Professional & scientific | 2007 |
| Coser's Electrical Ltd | Construction | 2024 |
| Cosgrove Decorators Limited | Construction | 2002 |
| Cosmed Couture Ltd | Health & social care | 2021 |
| Cosmic.Horse Ltd | Information & communication | 2021 |
| Costello Safety Limited | Professional & scientific | 2023 |
| Costello Site Safety Limited | Professional & scientific | 2013 |
| Coull SM Services Ltd | Construction | 2025 |
| Coulson Bioinformatics Ltd | Professional & scientific | 2017 |
| Coulter OIL & GAS Ltd | Professional & scientific | 2022 |
| Countrywise Leisure Limited | Administrative & support | 1997 |
| Courageous Safety Consultants Limited | Professional & scientific | 2025 |
| Cousins Kitchen Ltd | Hospitality | 2025 |
| CP Inspection and Maintenance Limited | Manufacturing | 2014 |
| CR Renewable Solutions Ltd | Professional & scientific | 2025 |
| Crafters’ Drop-In C.I.C. | Wholesale & retail | 2024 |
| Crafty Monkey Brewing Co Limited | Manufacturing | 2017 |
| Craigarran Limited | Health & social care | 2015 |
| Cram Holdings Ltd | Real estate | 2019 |
| Cranwell Motors Limited | Manufacturing | 2002 |
| Create Images ION Limited | Wholesale & retail | 1996 |
| Creative Agenda Ltd | Professional & scientific | 2019 |
| Creative Community Enterprise CIC | Health & social care | 2021 |
| Creative Management NE Limited | Arts & recreation | 2023 |
| Creative Minds North East CIC | Education | 2020 |
| Creme Services Ltd | Construction | 2016 |
| Critical Cards Ltd | Wholesale & retail | 2024 |
| Croft Construction NE Limited | Construction | 2013 |
| Croft Plumbing, Heating, Electrical Contractors Ltd | Construction | 2017 |
| Croft Residential Lettings Limited | Real estate | 2015 |
| Crooks Barn Lane Engineering Ltd | Professional & scientific | 2018 |
| Crossroads Tattoo Studio Limited | Arts & recreation | 2015 |
| Crown English Ltd | Education | 2025 |
| Crowngreen Limited | Construction | 2010 |
| Crtr Holdings Ltd | Financial services | 2021 |
| Crtr Ltd | Professional & scientific | 2016 |
| Crumbs Yarm Limited | Hospitality | 2021 |
| Crusader Lifting Services Ltd | Professional & scientific | 2019 |
| Crusader Property Limited | Wholesale & retail | 2025 |
| Crypto Engineering Ltd | Professional & scientific | 2018 |
| Crystal Edge Trading Ltd | Wholesale & retail | 2023 |
| Crystal Hartlepool Limited | Hospitality | 2021 |
| Crystal Maids Domestic Cleaning Ltd | Administrative & support | 2023 |
| CS BEL Teesside Ltd | Construction | 2026 |
| CS Optics Ltd | Construction | 2023 |
| CSG Safety Solutions Ltd | Health & social care | 2025 |
| Csjsts Engineering Ltd | Construction | 2024 |
| Cstldn Studios Ltd | Real estate | 2021 |
| CT Tech Limited | Construction | 2024 |
| Curios House Finance Lending Limited | Financial services | 2022 |
| Curios House Finance Limited | Financial services | 2010 |
| Curios House Gifted 555 Limited | Wholesale & retail | 2022 |
| Curios House Gifted Limited | Wholesale & retail | 2022 |
| Curios House Limited | Wholesale & retail | 2010 |
| Curious Arts | Arts & recreation | 2017 |
| Custom Windows Ltd | Wholesale & retail | 2007 |
| Custos Safety Ltd | Professional & scientific | 2026 |
| Cwbjointingservices Ltd | Construction | 2022 |
| CWW Construct Limited | Construction | 2023 |
| Cwwoods Ltd | Information & communication | 2013 |
| Cyclone Rigging Limited | Construction | 2013 |
| D & M Cabling Solutions Limited | Construction | 2012 |
| D and C Electricians Ltd | Construction | 2026 |
| D Barker Services Ltd | Construction | 2012 |
| D C Material Management Limited | Mining & quarrying | 2019 |
| D C Materials and Logistics Limited | Professional & scientific | 2026 |
| D Findlay Limited | Professional & scientific | 2013 |
| D Harker Supplies Ltd | Wholesale & retail | 2008 |
| D Hersi Electricals Limited | Construction | 2017 |
| D L M Property Repairs Ltd | Manufacturing | 2024 |
| D Stephenson North East Limited | Other services | 2023 |
| D T Solutions (NE) Ltd | Construction | 2009 |
| D W M Offshore Limited | Construction | 2015 |
| D&D Painting and Decorating Services Ltd | Construction | 2026 |
| D&H Civils Ltd | Administrative & support | 2025 |
| D&L Plumbing & Heating (NE) Limited | Construction | 2015 |
| D. E. M. S. B Limited | Construction | 2011 |
| D. H. Potter Construction Limited | Construction | 2017 |
| D.P.S Dent Plumbing Services Ltd | Construction | 2022 |
| D.S.J Site Services Ltd | Administrative & support | 2024 |
| D2D Solar Services Ltd | Construction | 2020 |
| Daaj Ltd | Wholesale & retail | 2018 |
| DAC Electrical Services Limited | Construction | 2025 |
| DAC Inspection Services Ltd | Construction | 2016 |
| Daisy and Beas C.I.C. | Hospitality | 2020 |
| Daisy and Beas Highlight Ltd | Hospitality | 2026 |
| Dakota Systems Ltd | Construction | 2026 |
| Dalton Autos Limited | Wholesale & retail | 2008 |
| Dalton Lodge Ltd | Hospitality | 2019 |
| Dalydarby Media Ltd | Information & communication | 2024 |
| DAN Perry Productions Ltd | Information & communication | 2009 |
| Danab Limited | Financial services | 2002 |
| Danby Fish Limited | Wholesale & retail | 2024 |
| Dancing CUP Group Ltd | Hospitality | 2025 |
| Dancing CUP Middleton Grange Ltd | Hospitality | 2026 |
| Dandelion Cleaning Ltd | Administrative & support | 2026 |
| Daniel Marc Consulting Limited | Professional & scientific | 2018 |
| Daniel Marc Property Limited | Real estate | 2024 |