| Building Mechanical Maintenance Services Limited | Construction | 2020 |
| Bull in a Barbershop Ltd | Other services | 2022 |
| Bullseye Cleaning Ltd | Administrative & support | 2014 |
| Bumblebee Strategies Ltd | Information & communication | 2023 |
| Bumps Away UK Limited | Wholesale & retail | 2017 |
| Burliss Properties Limited | Real estate | 2012 |
| Burnham Waters 2 Ltd | Construction | 2022 |
| Burnham Waters 3 Ltd | Construction | 2022 |
| Burnham Waters Ltd | Construction | 2020 |
| Burnham Waters Management (2024) Limited | Households | 2024 |
| Burritos and Bowls Ltd | Hospitality | 2026 |
| Business Voip & Data Limited | Information & communication | 2024 |
| Buta Construction Ltd | Construction | 2017 |
| Butek Group Limited | Manufacturing | 2019 |
| Butek Landline Limited | Manufacturing | 2014 |
| Buttsbury Pre-School | Education | 2010 |
| Buttsbury Primary School | Education | 2011 |
| Buy Prop Limited | Real estate | 2020 |
| Buy to LET (Yorkshire) Ltd | Real estate | 2022 |
| BXT Management Limited | Administrative & support | 2014 |
| C & P (UK) Ltd | Other services | 2010 |
| C Byrne & Sons London Limited | Construction | 2017 |
| C H Containers Limited | Transport & logistics | 2021 |
| C K R Telecom Limited | Information & communication | 2012 |
| C Knight Dance School Ltd | Arts & recreation | 2023 |
| C M Pallet Services Limited | Transport & logistics | 2012 |
| C S White Consultancy Ltd | Professional & scientific | 2019 |
| C. & L. Plant Limited | Construction | 1973 |
| C. Bateman and Sons Ltd | Extraterritorial | 2012 |
| C. K. H. Facilities Limited | Construction | 2015 |
| C.A.D. Management Services Limited | Professional & scientific | 1999 |
| C.H Tree Care Ltd | Administrative & support | 2023 |
| C.Tomov Building Services Limited | Construction | 2008 |
| C4BITS Limited | Information & communication | 2008 |
| C5 Property Group Limited | Real estate | 2023 |
| C5 Property Investments Limited | Real estate | 2019 |
| CA Digital Ltd | Information & communication | 2019 |
| CAB Consult Ltd | Professional & scientific | 2022 |
| Cactus 8 Ltd | Real estate | 2018 |
| CAD Holdings Limited | Professional & scientific | 2001 |
| Cad-Man (UK) Limited | Manufacturing | 2013 |
| Cadman Property Holdings Ltd | Real estate | 2024 |
| Caelum Moffatt Consulting Ltd | Other services | 2022 |
| Cafe Air Limited | Hospitality | 2024 |
| Cafe O'Portugues Limited | Hospitality | 2017 |
| Caffe Piaggio Ltd | Hospitality | 2006 |
| Calloway QS Services Ltd | Professional & scientific | 2026 |
| Calmarsh Limited | Real estate | 2026 |
| Campo Inc Ltd | Administrative & support | 2012 |
| Canine Advisory Dog Training Ltd | Wholesale & retail | 2020 |
| Canine Advisory Ltd | Other services | 2014 |
| Canine Aquatic Leisure Ltd | Arts & recreation | 2023 |
| Cantron Developments Limited | Professional & scientific | 2014 |
| CAP Coffee Company Ltd | Wholesale & retail | 2025 |
| Capexia Limited | Construction | 2014 |
| Capital Air CON Limited | Energy | 2018 |
| Capital Computer Care Limited | Other services | 1988 |
| Capital Heritage Ltd | Construction | 2018 |
| Capital Holdings Real Estate Limited | Real estate | 2022 |
| Capital Land Partners LLP | | 2011 |
| Capital Lettings Plus Limited | Real estate | 2019 |
| Capstain Venture Ltd | Real estate | 2011 |
| Care Compliance Ltd | Professional & scientific | 2018 |
| Care Environmental Ltd | Administrative & support | 2009 |
| Care Safety Ltd | Administrative & support | 2020 |
| Care Surveyors Ltd | Professional & scientific | 2022 |
| CARING4PAWS Limited | Professional & scientific | 2016 |
| Carl Finn Consulting Ltd | Professional & scientific | 2018 |
| Carlene Noel Limited | Other services | 2015 |
| Carole Herman Education Consultancy Limited | Education | 2022 |
| Carpet Preservation Services Ltd | Other services | 2001 |
| Carpets & Floor Coverings Direct Limited | Wholesale & retail | 2004 |
| Carrera 100 Limited | Professional & scientific | 2021 |
| Casa Construction 01 Limited | Professional & scientific | 2023 |
| Casa Construction 02 Limited | Professional & scientific | 2023 |
| Casa Construction 03 Limited | Professional & scientific | 2023 |
| Casa Investments UK Ltd | Real estate | 2023 |
| Case Analytics Limited | Information & communication | 2018 |
| Casperlight Limited | Real estate | 2014 |
| Cassadian Homes (Bicester) Limited | Administrative & support | 2010 |
| Castle East Limited | Professional & scientific | 2025 |
| Castle Property Development Ltd | Construction | 2025 |
| Castor ARB Limited | Construction | 2016 |
| Cat Accounting Ltd | Professional & scientific | 2019 |
| Cat&Mol Ltd | Real estate | 2020 |
| Catch the Feeling Limited | Other services | 2019 |
| Cathedral Meadows Management Company Limited | Real estate | 1999 |
| Cavalier Print Services Limited | Manufacturing | 2017 |
| Cavaye Cocktails Ltd | Hospitality | 2026 |
| Caylock Management Limited | Real estate | 2017 |
| Caylock Properties Limited | Real estate | 2016 |
| CB Athletics Limited | Education | 2022 |
| CB Flavours Limited | Hospitality | 2019 |
| CB Secure Systems Installation Ltd | Administrative & support | 2023 |
| CBR Productions Limited | Professional & scientific | 2020 |
| CBY Transport Ltd | Transport & logistics | 2026 |
| CC Electrical Supplies Limited | Wholesale & retail | 2016 |
| Ccrs Sells Ltd | Wholesale & retail | 2022 |
| CCS Jeweltone Limited | Administrative & support | 2003 |
| Ccvs Tech Ltd | Information & communication | 2025 |