| C Newman Properties Ltd | Real estate | 2025 |
| C&A Global Solutions Ltd | Transport & logistics | 2023 |
| C&D Mechanical Limited | Construction | 2018 |
| C&J (UK) Consultants Ltd | Professional & scientific | 2023 |
| C&M Automotive Ltd | Wholesale & retail | 2026 |
| C.C. Plant and Commercial Limited | Manufacturing | 2017 |
| C.T.Butterfield and Sons Limited | Other services | 1964 |
| CAA Holdings Limited | Other services | 2019 |
| Cairns Property Holdings Limited | Real estate | 2026 |
| Calvin Dexter Financial Solutions Limited | Financial services | 2014 |
| Campagna Estates Limited | Real estate | 2017 |
| Campagna Holdings Limited | Real estate | 2018 |
| Campervan Furniture Limited | Manufacturing | 2017 |
| Campion Consulting Services Limited | Professional & scientific | 2024 |
| CAN Securities Limited | Real estate | 2008 |
| Caring Hands and Warm Hearts CIC | Information & communication | 2025 |
| Carls Cabin Limited | Wholesale & retail | 2024 |
| Carmotion Approved Limited | Wholesale & retail | 2020 |
| Carmotion Limited | Wholesale & retail | 2009 |
| Carole Training & Assessments Ltd | Education | 2025 |
| Carr Rail Ltd | Construction | 2023 |
| Casper’S Coffee House Limited | Hospitality | 2018 |
| Cast & Martin Limited | Wholesale & retail | 1977 |
| Catalyst Academy Limited | Professional & scientific | 2019 |
| Catalyst Processes Limited | Professional & scientific | 2021 |
| Caven Shaw Rail Limited | Manufacturing | 2019 |
| CB Comms Ltd | Construction | 2022 |
| Cbeproperties Flip Limited | Real estate | 2024 |
| Cbeshortstays Limited | Real estate | 2026 |
| CBF Developments Limited | Real estate | 2004 |
| CBW Professional Services Limited | Professional & scientific | 2014 |
| Ccjw Accounting Limited | Professional & scientific | 2021 |
| Ccjw Consulting Limited | Professional & scientific | 2021 |
| CCL Joinery (Swinton) Ltd | Construction | 2022 |
| Ceejays Bars Limited | Hospitality | 2019 |
| Central Building Rentals Ltd | Administrative & support | 2025 |
| Central Repair Centre Limited | Wholesale & retail | 2014 |
| Century Cladding Holdings Ltd | Real estate | 2023 |
| Century Furniture Ltd | Manufacturing | 2025 |
| CG Development & Consultancy Ltd | Professional & scientific | 2021 |
| CGC Developments Ltd | Construction | 2020 |
| CGM Access Services Ltd | Manufacturing | 2025 |
| CH Plumbing & Heating (Yorkshire) Limited | Construction | 2022 |
| Chambers Cars Limited | Wholesale & retail | 2018 |
| Chapel Mews Properties Limited | Households | 2001 |
| Charles Thompson (UK) Holdings Limited | Financial services | 2019 |
| Charles Thompson Limited | Manufacturing | 1974 |
| Cherith Financial Limited | Financial services | 2013 |
| Cherry Tree Care Home Limited | Administrative & support | 2014 |
| Chesman Holdings Limited | Financial services | 2021 |
| Chesman Properties Limited | Real estate | 2021 |
| Chesman Property Ltd | Real estate | 2023 |
| Chesman Underfloor Heating Ltd | Construction | 2022 |
| Chic & Unique Boutique Ltd | Wholesale & retail | 2026 |
| Chief Facilities Group Ltd | Administrative & support | 2026 |
| Chiral Accountants Ltd | Professional & scientific | 2018 |
| Chris Mason Coaching Ltd | Arts & recreation | 2025 |
| Chris Mason Performance Doncaster Limited | Arts & recreation | 2025 |
| Chris Mason Performance Rotherham Limited | Arts & recreation | 2025 |
| Chrisand Fabrications Limited | Manufacturing | 2002 |
| Church Hall Garage Limited | Wholesale & retail | 2015 |
| Circuits Electrical Limited | Construction | 2000 |
| CLB Roofing Ltd | Construction | 2019 |
| Climax Entertainments and Events Limited | Information & communication | 2021 |
| Clinical Outcomes Limited | Administrative & support | 2005 |
| Cliningsolution Ltd | Administrative & support | 2020 |
| Cloudcrunch Limited | Professional & scientific | 2010 |
| CLS MOT & Diagnostic Centre Limited | Wholesale & retail | 2001 |
| CM Warranties Limited | Wholesale & retail | 2020 |
| Cmbcatering Ltd | Hospitality | 2024 |
| CMD Car & Van Sales Ltd | Wholesale & retail | 2023 |
| CMW Building Solutions Limited | Construction | 2015 |
| Coal Face AI Ltd | Information & communication | 2025 |
| Coal Heritage Pension Trustees Limited | Financial services | 2025 |
| Coccolare Events Limited | Hospitality | 2024 |
| Cock of the North (Holdings) Limited | Financial services | 2023 |
| Cock of the North (Poultry) Limited | Agriculture & fishing | 2002 |
| Codingloop Limited | Wholesale & retail | 2026 |
| Combat Academy (Rotherham) Ltd | Arts & recreation | 2020 |
| Commercial & Logistics Ltd | Real estate | 2021 |
| Commercial Property Rotherham Ltd | Real estate | 2008 |
| Commercial Vehicle Direct Ltd | Wholesale & retail | 2010 |
| Complex Build Ltd | Construction | 2019 |
| Conisbrough Slaughtering Company Limited | | 1979 |
| Constant Security Services Limited | Administrative & support | 1985 |
| Construction Supplies and Services Ltd | Wholesale & retail | 2024 |
| Converted LLP | | 2018 |
| Cookes Installations Ltd | Construction | 2023 |
| Cool Cube Logistics Ltd | Transport & logistics | 2010 |
| Coopers Business Services Limited | Construction | 2008 |
| Corashleigh Estates Limited | Real estate | 2002 |
| Corrigan Hospitality Ltd | Hospitality | 2025 |
| County Roadworks Limited | Construction | 2002 |
| Courtney’S Cleaning Services Limited | Wholesale & retail | 2022 |
| Cpsp Holdings Ltd | Real estate | 2019 |
| Craig Hickin Plumbing & Heating Ltd | Construction | 2012 |
| Creare IT Ltd | Extraterritorial | 2023 |
| Creating Warmer Spaces Limited | Wholesale & retail | 2014 |
| Creative Nail Studio Limited | Other services | 2006 |
| CRS (Yorkshire) Ltd | Construction | 2025 |