| Carlton Food S80 Ltd | Hospitality | 2024 |
| Carlton IT Assistance Limited | Information & communication | 2013 |
| Carlton MOT Centre Limited | Wholesale & retail | 2018 |
| Carman Consultancy Ltd | Financial services | 2023 |
| Carmodities Limited | Wholesale & retail | 2011 |
| Carnoustie 1972 Limited | Extraterritorial | 2013 |
| Carr's Farming Limited | Wholesale & retail | 2017 |
| Carr's UK Limited | Agriculture & fishing | 2003 |
| Carter's Canines Ltd | Other services | 2021 |
| Cashflo (UK) Limited | Financial services | 1997 |
| Castle Jewellers (Worksop) Ltd | Wholesale & retail | 2018 |
| CATCH1905 Ltd | Hospitality | 2025 |
| CB Barbers Shop Ltd | Other services | 2025 |
| CBS ENG Consultants Limited | Construction | 2011 |
| CCJ Brundrit Transport Ltd | Transport & logistics | 2024 |
| CDE Rentals and Renovations Ltd | Real estate | 2024 |
| CDM Merchandise Ltd | Professional & scientific | 2024 |
| Cerealto UK Limited | Manufacturing | 1999 |
| Chalice Medical Limited | Manufacturing | 1998 |
| Chameleon (Retford) Ltd | Professional & scientific | 2013 |
| Chameleon (Tickhill) Limited | Professional & scientific | 2004 |
| Charm Windows Limited | Construction | 1993 |
| Cheethams (Worksop) Limited | Financial services | 1941 |
| Chef's Perspective Limited | Hospitality | 2025 |
| Cherry Grove Development Limited | Construction | 2026 |
| Chestnut Grove (Shireoaks) Management Company Limited | Households | 2021 |
| Chick'N Slice Limited | Hospitality | 2026 |
| Chimelda Limited | Information & communication | 2026 |
| Chimera Financial Solutions Limited | Financial services | 2012 |
| Chocolate Orange (MD) Limited | Hospitality | 2017 |
| Choice Housing | Real estate | 2014 |
| Choose Purple Limited | Information & communication | 2014 |
| Chris Breen Management & Consulting Ltd. | Professional & scientific | 2018 |
| Chris Lakey Jewellery Limited | Manufacturing | 2024 |
| Chris Mather Mechanical Services Limited | Professional & scientific | 2025 |
| Chris Moore Joinery Ltd | Construction | 2019 |
| Chrisrushayes Limited | Health & social care | 2013 |
| Ciesielski Transport Limited | Transport & logistics | 2021 |
| CIJ Consultancy Ltd | Professional & scientific | 2025 |
| Cindy Top Chef Ltd | Hospitality | 2019 |
| Cints Plumbing and GAS Heating Ltd | Construction | 2024 |
| City York Limited | Wholesale & retail | 2025 |
| CJ Frank Property Limited | Real estate | 2020 |
| CJV Engineering Ltd | Manufacturing | 2022 |
| CK Leases Ltd | Real estate | 2024 |
| Claire Latreille Consultancy Ltd | Professional & scientific | 2021 |
| Clarity Healthcare Recruitment Ltd | Health & social care | 2013 |
| Clariva Holdings Limited | Professional & scientific | 2022 |
| Clariva PLC | Professional & scientific | 2012 |
| Clark Recruitment Services Ltd | Administrative & support | 2013 |
| Clarke's Rentals Ltd | Real estate | 2025 |
| Claylands Wines Limited | Agriculture & fishing | 2015 |
| Claylite Aggregates Limited | Manufacturing | 2000 |
| CLC Housing Limited | Real estate | 2025 |
| CLC Machining Limited | Wholesale & retail | 2015 |
| Clean @ CUT Limited | Manufacturing | 2015 |
| Cleaning Perfect Ltd | Wholesale & retail | 2023 |
| Clear the Decks Ltd | Administrative & support | 2020 |
| Clearcrest Exterior Care Ltd | Administrative & support | 2026 |
| Cleo Healthcare Limited | Public administration | 2021 |
| Cloudre Ltd | Administrative & support | 2020 |
| CLS Machining Ltd | Manufacturing | 2013 |
| Clumber Agriculture Ltd | Agriculture & fishing | 2023 |
| Clumber Kitchens Limited | Wholesale & retail | 2016 |
| Clumber Livery Limited | Agriculture & fishing | 2012 |
| Clumber Pigs Ltd | Agriculture & fishing | 2014 |
| Clumber Products Ltd | Manufacturing | 2020 |
| CM Quality Services Limited | Professional & scientific | 2022 |
| CMH Electrical Ltd | Construction | 2025 |
| CNC Contracting Ltd | Manufacturing | 2025 |
| Coach Check App Ltd | Information & communication | 2025 |
| Coburg Homes Ltd | Real estate | 2013 |
| Codeui Limited | Information & communication | 2022 |
| Coggan Commercial Surveying Limited | Real estate | 2003 |
| Cognitronics Limited | Information & communication | 1977 |
| Collinghamco Ltd | Professional & scientific | 2024 |
| Colman Transport Limited | Transport & logistics | 1991 |
| Colmo Investments Limited | Real estate | 2024 |
| Composite Centre Limited | Professional & scientific | 2021 |
| Concept REI Limited | Real estate | 2026 |
| Concrete Drilling UK Limited | Construction | 2024 |
| Confident Home Care Limited | Health & social care | 2022 |
| Connected Hospitality Limited | Information & communication | 2024 |
| Construction by REA Ltd | Construction | 2025 |
| Construction, Rail and Engineering Recruitment Ltd | Administrative & support | 2020 |
| Cool - Air (Worksop) Ltd | Energy | 2009 |
| Cooper Security Systems Limited | Administrative & support | 2002 |
| Coos Trans Ltd | Transport & logistics | 2019 |
| Corey Mitchell Cladding Services Limited | Construction | 2022 |
| Cormed-Dx Ltd | Wholesale & retail | 2022 |
| Cornerstone Cleaning Services Limited | Administrative & support | 2025 |
| Corton CAD Solutions Ltd | Administrative & support | 2013 |
| Corus Commercial Vehicles Limited | Wholesale & retail | 2021 |
| Cosma Distribution Ltd | Transport & logistics | 2021 |
| Costa Food Ltd | Other services | 2025 |
| Cosy Fireplaces Limited | Wholesale & retail | 2013 |
| COT Electrical Ltd | Construction | 2020 |
| Counter Measure Limited | Information & communication | 2013 |
| Countywide Homecare & Construction Ltd | Construction | 2015 |
| Courier Translog Ltd | Transport & logistics | 2019 |