| Cheshire Consulting Limited | Professional & scientific | 2008 |
| Chester Systems Limited | Information & communication | 1993 |
| Chill Anaesthesia Ltd | Health & social care | 2019 |
| Chloe Upson Physiotherapy and Yoga Services Ltd | Other services | 2019 |
| Chloe Upson Physiotherapy Limited | Health & social care | 2015 |
| Chloe Upson Physiotherpay Holdings Limited | Health & social care | 2020 |
| Chlor Tech Services Ltd | Financial services | 2021 |
| Chris Clark Architectural Services Limited | Professional & scientific | 2005 |
| Church Hill Properties Limited | Real estate | 2002 |
| Churchside Mews Management Company Limited | Real estate | 2004 |
| Cider Solutions Limited | Professional & scientific | 2006 |
| Circle Loft Ltd. | Administrative & support | 2017 |
| Circling Squares Ltd | Professional & scientific | 2019 |
| Cityspace Limited | Extraterritorial | 2009 |
| Cjheaps Consulting Limited | Administrative & support | 2018 |
| CL Sales Consultancy Ltd | Wholesale & retail | 2023 |
| Claire Collins Property Limited | Real estate | 2008 |
| Claypitts Chiropractic Limited | Health & social care | 2024 |
| Claypitts Holdings Limited | Professional & scientific | 2025 |
| Clean Specialist Commercial Cleaners Ltd | Administrative & support | 2005 |
| Clear Water Supplies International Limited | Water & waste | 2014 |
| Clear Water Supplies Ltd. | Professional & scientific | 2013 |
| Cleopatra`S Needle Limited | Wholesale & retail | 2007 |
| Cliftonthorpe (Management) Company Limited | Households | 2005 |
| Cliq Consulting Ltd | Information & communication | 2021 |
| CLK Associates (Yorkshire) Ltd | Information & communication | 2003 |
| Cloud Aviation Ltd | Manufacturing | 2022 |
| Cloudgear Ltd | Information & communication | 2022 |
| Clough Property Ltd | Real estate | 2023 |
| CLT Limited | Financial services | 2022 |
| CLT Property Limited | Real estate | 2022 |
| Clubscomplete Limited | Arts & recreation | 2010 |
| CM Training and Assessment Ltd | Education | 2021 |
| Coalville Trophy Centre Ltd | Wholesale & retail | 2023 |
| Code & Evolve Ltd | Information & communication | 2020 |
| Cognitive Audit and Risk Services Ltd | Information & communication | 2017 |
| Colca Ltd | Professional & scientific | 2018 |
| Collier Aggregates Ltd | Wholesale & retail | 2024 |
| Collier Plant Ltd | Construction | 2021 |
| Comfort Care Consulting Limited | Health & social care | 2023 |
| Comment Associates Limited | Professional & scientific | 2011 |
| Commercial Refurbishment Specialists Ltd | Construction | 2018 |
| Commstech Limited | Construction | 2017 |
| Communicate O.C.E Ltd | Health & social care | 2006 |
| Complete Catering & Marketing Services Ltd | Wholesale & retail | 2024 |
| Compusoft GB Limited | Information & communication | 1999 |
| Conductor Capital Limited | Professional & scientific | 2022 |
| Conscious Conduct Solutions Ltd | Professional & scientific | 2020 |
| Conshelco Ltd | Other services | 2023 |
| Consilio Holdco Limited | Financial services | 2022 |
| Consilio Intermediateco Limited | Financial services | 2021 |
| Consilio Midco Limited | Financial services | 2021 |
| Consilio Topco Limited | Financial services | 2021 |
| Consult B Naylor Ltd | Professional & scientific | 2025 |
| Content Flow Limited | Information & communication | 2013 |
| Conway Land Management Ltd | Construction | 2000 |
| Cookie & Crumb Limited | Manufacturing | 2026 |
| Coombegrove Limited | Real estate | 1999 |
| Copyprint (Bromley) Limited | Manufacturing | 1985 |
| Cording IT Solutions Limited | Information & communication | 2007 |
| Cordson Property Solutions Ltd | Real estate | 2017 |
| Cosec Support Services Ltd | Administrative & support | 2005 |
| Cotswold Diesel Railcar Ltd | Transport & logistics | 2011 |
| Cotswold Holiday Breaks LLP | | 2024 |
| County Battery Services Limited | Manufacturing | 1996 |
| Coxon Electrical Limited | Construction | 2011 |
| CPC Electrical Services Ltd | Wholesale & retail | 2005 |
| CPP Ventures Ltd | Professional & scientific | 2023 |
| Crane Hire Solutions Limited | Construction | 2003 |
| Create and Print Limited | Wholesale & retail | 2025 |
| Creative Grids (UK) Limited | Manufacturing | 2000 |
| Creative Security Solutions Limited | Administrative & support | 2000 |
| Crewe Property Management Limited | Real estate | 2014 |
| CRG Aerospace Consulting Ltd | Professional & scientific | 2021 |
| Crime & Fire Defence Systems Limited | Administrative & support | 1999 |
| Criterion Analytics Ltd | Administrative & support | 2018 |
| Croft Domestic Services Limited | Professional & scientific | 2022 |
| Cross Paramedical Limited | Health & social care | 2014 |
| Crowned Confidence Coaching Ltd | Health & social care | 2025 |
| Croydon-Fowler Construction Ltd | Construction | 2016 |
| Crummie (Holdings) Limited | Financial services | 2017 |
| CT Glass and Glazing Ltd | Construction | 2021 |
| Ctrl Media Group Limited | Information & communication | 2021 |
| Cuckoo GAP Limited | Administrative & support | 1987 |
| Curated Rooms Ltd | Real estate | 2025 |
| Cureton Consulting Limited | Professional & scientific | 2007 |
| Custodian Plant Ltd | Construction | 2019 |
| D & H Rentals Ltd | Hospitality | 2018 |
| D & J Golly Limited | Financial services | 2015 |
| D & N Solutions Limited | Manufacturing | 2007 |
| D E M Hawkes Limited | Professional & scientific | 2019 |
| D Jain Solutions Limited | Information & communication | 2006 |
| D M Ennis Limited | Financial services | 2022 |
| D R Dickins Limited | Health & social care | 2018 |
| D R Price Associates Limited | Health & social care | 2002 |
| D Wright Utilities Limited | Energy | 2019 |
| D&E Business Marketing Ltd | Professional & scientific | 2018 |
| D&L COX Ltd | Financial services | 2019 |
| D&M Rides Ltd | Arts & recreation | 2026 |
| D-Esco Ltd | Professional & scientific | 2022 |