| CDG Engineering Services Limited | Construction | 2014 |
| CDM 360 Solutions Limited | Professional & scientific | 2026 |
| CE LA VI Living Ltd | Real estate | 2025 |
| Cece Plumbing & Heating Ltd | Construction | 2023 |
| Cedas S Ltd | Hospitality | 2016 |
| Celebrate-Now.Com Ltd. | Information & communication | 2026 |
| Celoriva Limited | Wholesale & retail | 2026 |
| Cels Business Services Limited | Professional & scientific | 2006 |
| Central PAD Ltd | Hospitality | 2011 |
| Centralus 022 Ltd | Administrative & support | 2019 |
| Centralus 023 Ltd | Administrative & support | 2019 |
| Centralus Spare 3 Limited | Administrative & support | 2020 |
| Centralus Spare 4 Limited | Administrative & support | 2020 |
| CF Fertilisers UK Limited | Manufacturing | 1997 |
| CF Industries (UK) Limited | Manufacturing | 2015 |
| CF System Solutions Ltd | Information & communication | 2019 |
| CG Auto Services Limited | Professional & scientific | 2021 |
| CH Consult Ltd | Professional & scientific | 2023 |
| CH Planning & Scheduling Limited | Construction | 2018 |
| CH Solutions Limited | Construction | 2009 |
| Challenge Wellbeing Limited | Health & social care | 2021 |
| Chambers Music Limited | Education | 2023 |
| Chan & Chan Ltd | Real estate | 2019 |
| Chan & LY Ltd | Real estate | 2019 |
| Chantelle Scott Coaching Ltd | Arts & recreation | 2025 |
| Chawla Professional Services Limited | Health & social care | 2010 |
| Cherry Orchards Care Ltd | Health & social care | 2014 |
| Cherry Tree Properties (N.E) Ltd | Real estate | 2023 |
| Chisholm Group Limited | Financial services | 2019 |
| Chitale Family Partnership LLP | | 2020 |
| Chitale Property Services Limited | Construction | 2015 |
| Chiu & Thong Holdings Ltd | Real estate | 2022 |
| Chiu & Thong Partnership LLP | | 2022 |
| Chorlex Consultancy LLP | | 2016 |
| Chosen and Crowned Ltd | Administrative & support | 2025 |
| Chris Beaney Bookkeeping Services Limited | Professional & scientific | 2015 |
| Chris Brogan Family Holdings Limited | Real estate | 2018 |
| Chris Eaton Consultants Limited | Professional & scientific | 2014 |
| Chris Musgrave Limited | Construction | 2002 |
| Christian Alexander Limited | Wholesale & retail | 2015 |
| Christie Coaching Limited | Education | 2021 |
| Ciao Consultancy Ltd | Professional & scientific | 2025 |
| CIS Services (North East) Limited | Construction | 2010 |
| Citro Outdoor Creations Ltd | Administrative & support | 2026 |
| Cityside Estates Limited | Real estate | 2011 |
| CJ Design Engineering Limited | Professional & scientific | 2017 |
| CJ Partners LLP | | 2022 |
| CJC Residential Limited | Real estate | 2025 |
| CJS Engagement Ltd | Professional & scientific | 2021 |
| Cjsr Ltd | Construction | 2018 |
| Cjwilson Ltd | Administrative & support | 2023 |
| CK Electrical Engineering Ltd | Professional & scientific | 2025 |
| Claire Barrow Limited | Professional & scientific | 2013 |
| Clarity Anaesthesia Limited | Health & social care | 2024 |
| Clarke Family Limited | Real estate | 2023 |
| Clarke Property Partnership LLP | | 2023 |
| Classic Yachts Fine Arts Ltd | Construction | 2011 |
| Clayton Vehicle Solutions Limited | Professional & scientific | 2011 |
| Cleasby Compliance Limited | Professional & scientific | 2014 |
| Cleveland Fire Safety Limited | Public administration | 2021 |
| Cleveland Powder Coating Ltd | Wholesale & retail | 2019 |
| Cleveland Residential Limited | Real estate | 2016 |
| Cleveland Retail Ltd | Wholesale & retail | 2022 |
| Clickflow Group Limited | Financial services | 2026 |
| Clie Inspection Services Ltd | Professional & scientific | 2024 |
| Clinic N Limited | Other services | 2026 |
| Cliniconsult Limited | Professional & scientific | 2017 |
| Clough Comms Ltd | Administrative & support | 2017 |
| Clover Sports Management Ltd | Arts & recreation | 2019 |
| Clover Traffic Management (Leeds) Ltd | Construction | 2020 |
| Clymps Ltd | Financial services | 2024 |
| CM93 Engineering Ltd | Construction | 2023 |
| CMA CGM Inland Services UK Ltd. | Transport & logistics | 1988 |
| CMD Recycling Limited | Wholesale & retail | 2020 |
| CMS Project Delivery Limited | Professional & scientific | 2016 |
| Cnmp Properties Partnership LLP | | 2016 |
| CNS Auto Electrics Ltd | Wholesale & retail | 2024 |
| Coaching Connection Ltd | Arts & recreation | 2007 |
| Coastal Productions Limited | Information & communication | 1996 |
| Coatham Ltd | Health & social care | 2020 |
| Cobbles to Country Cottages Limited | Real estate | 2025 |
| Cognexa Ltd | Wholesale & retail | 2025 |
| Colehouse Communications Limited | Information & communication | 2013 |
| Colin Wheelhouse Consultancy Ltd | Professional & scientific | 2024 |
| Collins Family Partnership LLP | | 2020 |
| Colton (JEF) Ltd. | Wholesale & retail | 1979 |
| Comfort Supplies Ltd | Wholesale & retail | 2016 |
| Commercial Land Investments Limited | Real estate | 2020 |
| Communicate Technology Limited | Information & communication | 2011 |
| Communicateplc Ltd | Information & communication | 2015 |
| Community Interest Family Partnership LLP | | 2020 |
| Community Interest Ltd | Real estate | 2020 |
| Conex Tooling Solutions Ltd | Manufacturing | 2023 |
| Confidence Property Ltd | Real estate | 2015 |
| Conlan Automotive Fleet Services Ltd | Wholesale & retail | 2025 |
| Conscious Content Limited | Professional & scientific | 2020 |
| Consett DP Limited | Wholesale & retail | 2012 |
| Console Heaven Limited | Wholesale & retail | 2022 |
| Consult NET Zero Ltd | Professional & scientific | 2023 |
| Consultancy Management & Procurement Limited | Professional & scientific | 2021 |