| Bower Brothers Trading Ltd | Wholesale & retail | 2025 |
| Bp-Ra Consultancy Services Limited | Construction | 2025 |
| Bradshawbeau KBD Ltd | Wholesale & retail | 2025 |
| Branch Walkway Cafe Limited | Hospitality | 2017 |
| Brass Monkey Guisborough Ltd | Wholesale & retail | 2021 |
| Briight Line Gulf Limited | Wholesale & retail | 2025 |
| Bruces BD Ltd | Hospitality | 2025 |
| Bubbles Hand Services Ltd | Wholesale & retail | 2023 |
| Buck North East Limited | Construction | 2008 |
| Buildhire Solutions Ltd | Administrative & support | 2025 |
| Bull and Bone Pet Supplies Ltd | Wholesale & retail | 2026 |
| Bulmer Property Limited | Real estate | 2023 |
| C Sollett Ltd | Real estate | 2022 |
| C-Tech Solutions Limited | Information & communication | 2012 |
| C.J. Leonard & Sons (Holdings) Limited | Financial services | 2025 |
| C.J. Leonard & Sons Limited | Wholesale & retail | 1998 |
| Cafe Slapewath Ltd | Hospitality | 2024 |
| Cakeface Cycle Club Ltd | Wholesale & retail | 2024 |
| Candlewick of Guisborough Limited | Wholesale & retail | 2013 |
| Carbon SIX Engineering Limited | Professional & scientific | 2013 |
| Carp Life Competitions Limited | Wholesale & retail | 2023 |
| Castello Pizza Ltd | Hospitality | 2024 |
| Cataldo's Leisure Ltd | Wholesale & retail | 2025 |
| Cataldo's Pizzeria Limited | Hospitality | 2023 |
| Catch Life Tackle Ltd | Manufacturing | 2026 |
| Cats Whiskers Coffee Culture Limited | Hospitality | 2006 |
| CEG Technical Ltd | Professional & scientific | 2014 |
| CFT Conversions Ltd | Construction | 2021 |
| CGC Design Limited | Construction | 2020 |
| Chaloner Engineering Ltd | Information & communication | 1993 |
| Charles William Commercial Ltd | Administrative & support | 2020 |
| Charles William Garden Maintenance Ltd | Administrative & support | 2020 |
| CJA Property Limited | Construction | 2026 |
| CJN Engineering Services Ltd | Professional & scientific | 2024 |
| Claire's Daffodils Limited | Health & social care | 2025 |
| Clarity Counselling North East Ltd | Health & social care | 2023 |
| CLC Engineering Limited | Construction | 2019 |
| Cleopatra Pizza BEN Ltd | Hospitality | 2025 |
| Cleopatra Pizza UK Limited | Hospitality | 2026 |
| Cleveland Equine Services Limited | Professional & scientific | 2019 |
| Cleveland Land Services (Group) Limited | Extraterritorial | 2024 |
| Cleveland Land Services (Guisborough) Limited | Construction | 1978 |
| Cleveland Property and Garden Maintenance Ltd | Construction | 2020 |
| Cleveland School Sport Partnership CIC | Education | 2023 |
| Cleveland Tyre Services Ltd | Wholesale & retail | 2024 |
| Clevestone Properties Ltd | Real estate | 2016 |
| Cloud Nine Play Cafe Ltd | Hospitality | 2025 |
| Club Buddie Limited | Other services | 2012 |
| Club Buddy Limited | Other services | 2012 |
| CMB Dental Laboratory Ltd | Health & social care | 2019 |
| CMM Group Limited | Real estate | 2006 |
| CMP Consultants Ltd | Information & communication | 2019 |
| Coco Hill Ltd | Professional & scientific | 2018 |
| Colab Developments Ltd | Extraterritorial | 2017 |
| Colbert Leisure Limited | Hospitality | 2022 |
| Computing Systems Ltd | Information & communication | 2022 |
| Confi Consultancy Limited | Information & communication | 2024 |
| Connect Builds NE Ltd | Construction | 2018 |
| Contemporary Franchising Limited | Other services | 2024 |
| Contemporary Holdings Limited | Professional & scientific | 2003 |
| Contemporary Ltd | Other services | 2023 |
| Contemporary Salons Limited | Other services | 2009 |
| Continuitypoint Limited | Financial services | 2025 |
| Cook & Wilks Construction Ltd | Construction | 2021 |
| Cooke & Mitre Ltd | Construction | 2010 |
| Cookfella's Limited | Hospitality | 2012 |
| Copperas Limited | Professional & scientific | 2019 |
| Core and Flow Ltd | Health & social care | 2024 |
| Cosmic Wonders Ltd | Education | 2025 |
| Cotec Technology Services Limited | Professional & scientific | 2016 |
| Cowleigh Gate Limited | Information & communication | 1998 |
| Craig Leather Limited | Professional & scientific | 2010 |
| Create a Hype Ltd | Information & communication | 2026 |
| CT Engineering and Rigging Services Limited | Information & communication | 2024 |
| Cttorvill Ltd | Hospitality | 2025 |
| D L Property Developments NE Limited | Construction | 2021 |
| D M Hodgkiss Limited | Other services | 2023 |
| D.A.Williams Construction Ltd | Construction | 2020 |
| D.J.R. Smith Renewables Ltd | Construction | 2024 |
| Daf-Construction Ltd | Construction | 2022 |
| Dataguard Corporation Limited | Administrative & support | 2003 |
| David Sharples Site Services Ltd | Construction | 2017 |
| DB Sameday Couriers Ltd | Wholesale & retail | 2025 |
| DBT Engineering Ltd | Professional & scientific | 2024 |
| DCF Engineering Ltd | Professional & scientific | 2022 |
| Debmark Project Services Ltd | Construction | 2025 |
| Decked OUT TCG Ltd | Wholesale & retail | 2024 |
| Delegate Accounting CIC | Professional & scientific | 2025 |
| Delta Intelligence Limited | Information & communication | 2025 |
| Denham Hair and Beauty Studio Ltd | Other services | 2022 |
| Dependable Lettings Ltd | Real estate | 2024 |
| Derwent Plant Services Limited | Manufacturing | 2023 |
| Design-E-Lec Ltd | Construction | 2014 |
| Deuce Social Limited | Hospitality | 2026 |
| Dexcon Limited | Professional & scientific | 2026 |
| DH Lifting Services Ltd | Construction | 2024 |
| Diplomats Bureau Limited | Professional & scientific | 2020 |
| Discovery Digital Marketing Limited | Professional & scientific | 2016 |
| DJ Building & Scaffolding (NE) Ltd | Construction | 2024 |
| DJK Electrical Services Limited | Professional & scientific | 2019 |