| Business Environment Head Office Limited | Administrative & support | 2007 |
| Business Environment Milton Keynes Limited | Administrative & support | 2006 |
| Business Environment NO.1 Limited | Administrative & support | 2006 |
| Business Environment NO.7 Limited | Administrative & support | 2010 |
| Business Environment Soanepoint Limited | Administrative & support | 2006 |
| Business Environment Virtual Offices Limited | Administrative & support | 2013 |
| Business Environment Wembley Limited | Administrative & support | 2006 |
| Business View Ltd | Administrative & support | 2016 |
| Businessfitnessuk Limited | Construction | 2014 |
| Busylizzy Herts Limited | Other services | 2021 |
| Butlers and Colonial Wharves Management Limited | Households | 1998 |
| Butterfly Business Co Ltd | Information & communication | 2026 |
| BVN Haus Ltd | Real estate | 2026 |
| BVO Consulting Ltd | Professional & scientific | 2024 |
| BVR Consult (UK) Ltd | Professional & scientific | 2014 |
| Byewaters Estate Management Company Limited | Households | 1998 |
| Byla Games Ltd | Information & communication | 2023 |
| Byun & Co Limited | Professional & scientific | 2019 |
| C & J Solutions (SE) Ltd | Construction | 2021 |
| C & P Management (Woolwich) Limited | Real estate | 2005 |
| C & R Building Solutions Limited | Construction | 2016 |
| C 4 Urselves Limited | Information & communication | 2017 |
| C a Abbiss Limited | Real estate | 1976 |
| C Fennelly Ltd | Information & communication | 2013 |
| C J H Promotions Limited | Other services | 2025 |
| C J Trading Associates Limited | Financial services | 2013 |
| C P Timber Limited | Wholesale & retail | 2025 |
| C-Suite Advisory Ltd | Information & communication | 2020 |
| C-Wise Property Investment Ltd | Real estate | 2019 |
| C. Woodward Consultancy Ltd | Extraterritorial | 2015 |
| C.A.M. Auto Developments Limited | Wholesale & retail | 1998 |
| C.E.S. Engineering UK Ltd | Professional & scientific | 2023 |
| C.Lingi Electrical Ltd | Construction | 2023 |
| C.O.Tilney Limited | Extraterritorial | 1946 |
| C.P.S. (H) Limited | Professional & scientific | 2001 |
| C.S Roofing Services Limited | Construction | 2019 |
| C.S. Process Engineering Limited | Professional & scientific | 2001 |
| CA Electrical Solutions Ltd | Construction | 2016 |
| CA Landscaping Limited | Administrative & support | 2026 |
| Caag Consulting Limited | Professional & scientific | 2014 |
| Cable Street Consulting Limited | Professional & scientific | 2025 |
| Cairnway Limited | Professional & scientific | 2003 |
| Caleb Homes Ltd | Real estate | 2024 |
| Calibre Auto Solutions Limited | Wholesale & retail | 2015 |
| Calish Ltd | Wholesale & retail | 2021 |
| CAM Investment Holdings Ltd | Real estate | 2020 |
| Cambar Engineering Limited | Manufacturing | 2001 |
| Cambridge Colour Render Ltd | Construction | 2023 |
| Cambridge Military Hospital (Aldershot) Management Company Limited | Real estate | 2021 |
| Cambridgeshire Artificial Grass Co Ltd | Administrative & support | 2011 |
| Camden Road WFC Ltd | Arts & recreation | 2024 |
| Camelphat Management Ltd | Real estate | 2023 |
| Cameo Commerce & Consulting Ltd | Wholesale & retail | 2024 |
| Cameron Payne Construction Ltd | Manufacturing | 2022 |
| Cameron Property Survey Ltd | Professional & scientific | 2009 |
| Camey BEE (London) Limited | Professional & scientific | 2016 |
| Camills Design Limited | Administrative & support | 2009 |
| Camo Group Ltd | Administrative & support | 2010 |
| Campbell Canoes Limited | Manufacturing | 2020 |
| CAN Art Ltd | Arts & recreation | 2026 |
| Canda Copying Limited | Wholesale & retail | 2021 |
| Cannons Court Management Company Limited | Households | 1988 |
| Cantrel Lodge Management Company Limited | Households | 1992 |
| Capa Valve Developments Limited | Other services | 2025 |
| Capa Valve Limited | Other services | 2012 |
| Capella Estates (Commercial) Limited | Real estate | 2016 |
| Capital Softeners Limited | Construction | 2017 |
| Caple Transport Services Limited | Transport & logistics | 2018 |
| Capri Property Developments & Home Improvements Ltd | Construction | 2023 |
| Capricorn Technology Limited | Information & communication | 2024 |
| Car History Check Limited | Information & communication | 2024 |
| Cara Inc Limited | Administrative & support | 1998 |
| Carbcam Ventures Ltd | Professional & scientific | 2024 |
| Carbon FC (Cambridge) Ltd | Financial services | 2021 |
| Carbon Funding Consultants Cambridge Ltd | Financial services | 2021 |
| Carbon Neutral Cleaning Ltd | Administrative & support | 2020 |
| Cardinal Properties Limited | Real estate | 1978 |
| Care in Herts Limited | Administrative & support | 2014 |
| Care Visions Healthy Ageing Ltd | Other services | 2020 |
| CARE2ELEVATE Ltd | Health & social care | 2023 |
| Carers in Hertfordshire | Health & social care | 2000 |
| Carey Associates -HR Search Ltd | Administrative & support | 2025 |
| Carlton Rhodes Associates Limited | Professional & scientific | 2017 |
| Carlton Rhodes Capital Limited | Real estate | 2017 |
| Carole Luck Marketing Limited | Professional & scientific | 2011 |
| Carpro Autos Limited | Wholesale & retail | 2023 |
| Carr Creative Services Limited | Professional & scientific | 2014 |
| Carrickfergus Precision Engineering Limited | Manufacturing | 2002 |
| Carter Hythe Limited | Financial services | 2019 |
| Carter School of Dance Limited | Education | 2009 |
| Cartouche UK London Limited | Manufacturing | 2006 |
| Casora Trading Ltd | Wholesale & retail | 2026 |
| Castellex Ltd | Manufacturing | 2015 |
| Castle Flooring Hertford Limited | Wholesale & retail | 2015 |
| Castle Street Hertford Management Limited | Households | 2002 |
| Castle Street Property Management Limited | Real estate | 1989 |
| Castleview BED & Breakfast Ltd | Hospitality | 2016 |
| Catalina Brusnevsky Signature Academy Ltd | Education | 2025 |
| Catalonia Residential Limited | Real estate | 2007 |
| Catalyst Coaching Clinics Ltd | Education | 2021 |