| Bach Visitor & Education Centre Limited | Education | 2006 |
| Bakers Butchers (Witney) Limited | Administrative & support | 1967 |
| Ball Colegrave Limited | Wholesale & retail | 1981 |
| Banbury (Baker's Dozen) Limited | Hospitality | 2003 |
| Banbury Heights Ltd. | Health & social care | 2003 |
| Banzai Action Sports Ltd. | Arts & recreation | 1998 |
| Barnsley Canister Co. Limited | Manufacturing | 1919 |
| Barry Callebaut Manufacturing (UK) Limited | Manufacturing | 1974 |
| Basin Capital Partners LLP | | 2008 |
| Bayfield Associates Ltd. | Professional & scientific | 1997 |
| BDS Vehicle Management Limited | Wholesale & retail | 2006 |
| Beadlight Limited | Manufacturing | 1987 |
| Beans&Blends Limited | Hospitality | 2021 |
| Beansheaf Limited | Professional & scientific | 1966 |
| Bear Video Ltd | Information & communication | 2024 |
| Beard Mill Clinic Limited | Health & social care | 2006 |
| Beechcroft Developments Limited | Construction | 1984 |
| Beechcroft Employee Benefits Trust Limited | Construction | 2003 |
| Beechcroft Limited | Construction | 2003 |
| Beechcroft UK Limited | Construction | 1994 |
| Bermondsey ST Limited | Real estate | 2007 |
| Berol Quarter Limited | Real estate | 2022 |
| Best Morning Star Limited | Health & social care | 2018 |
| Best Years Limited | Wholesale & retail | 1999 |
| Bezant Solutions Limited | Professional & scientific | 2005 |
| Bibbynet Limited | Information & communication | 1998 |
| Bicester Limited Partnership | | 2017 |
| Bicester Print Limited | Wholesale & retail | 2001 |
| Bird in Hand Limited | Hospitality | 2002 |
| BJ & R Foord Limited | Agriculture & fishing | 2003 |
| Blackbird Leys Neighbourhood Support Scheme Limited | Health & social care | 1991 |
| Blagrove Holdco Limited | Financial services | 2025 |
| Blayhall Marine Limited | Information & communication | 2014 |
| Blossom Heights Social Care Ltd | Health & social care | 2023 |
| Blue Cross | Wholesale & retail | 1940 |
| Blue Cross Trading Company Limited | Wholesale & retail | 1987 |
| Bluehill Limited | Professional & scientific | 1995 |
| Bonidon Limited | Construction | 1979 |
| Booktic Limited | Wholesale & retail | 2002 |
| Border Technology and Innovations (UK) Ltd | Wholesale & retail | 1997 |
| Borsuk Software Engineering Limited | Information & communication | 1996 |
| Boswell Management Limited | Real estate | 2004 |
| Bowren Limited | Professional & scientific | 1994 |
| Boyd Holborn Limited | Real estate | 2003 |
| Brady Corporation Limited | Other services | 2001 |
| Breathable Space Ltd | Wholesale & retail | 2025 |
| Bristol York Limited | Financial services | 2004 |
| Brook House Residential Care Home Ltd | Health & social care | 2005 |
| Brook House Trading Ltd | Wholesale & retail | 2003 |
| Brooker and Breeze Goldsmiths Limited | Wholesale & retail | 2003 |
| BRT Solutions Ltd | Information & communication | 2007 |
| Bscope Limited | Administrative & support | 2012 |
| Bukka.Bliss Limited | Wholesale & retail | 2024 |
| Burning Helix Limited | Information & communication | 2001 |
| Business Manoeuvres Limited | Professional & scientific | 2013 |
| Butler & Proctor Limited | Construction | 2007 |
| Butler-Valet School Domestic Agency Ltd | Administrative & support | 2018 |
| Buzz Holdco Limited | Financial services | 2026 |
| Buzzbroadcasts Limited | Professional & scientific | 2014 |
| BW H&S Ltd | Professional & scientific | 2022 |
| C & L Wood Holdings Limited | Financial services | 2002 |
| C & S Plumbing and Heating Limited | Construction | 2003 |
| C Houlihan Ltd | Professional & scientific | 2018 |
| C&R Carpentry & Renovations Limited | Manufacturing | 2021 |
| C. Parker & Sons Limited | Wholesale & retail | 1991 |
| C.N. Building Limited | Construction | 2002 |
| Cabs 4 U Ltd | Transport & logistics | 2014 |
| Cadre Solutions Limited | Professional & scientific | 1994 |
| CAE Aircrew Training Services PLC | Professional & scientific | 1997 |
| Caffyn Engineering Ltd | Manufacturing | 2020 |
| Caldecourt Carpets Limited | Wholesale & retail | 2002 |
| Calm Control Systems Limited | Professional & scientific | 2003 |
| Cameco UK Ltd | Administrative & support | 2023 |
| Capricorn Controls Limited | Manufacturing | 1996 |
| Carnaudmetalbox Group UK Ltd. | Professional & scientific | 1988 |
| Carnaudmetalbox Overseas Ltd. | Professional & scientific | 1948 |
| Carter Manufacturing Limited | Wholesale & retail | 2003 |
| Caversfield Management Company Limited | Households | 1982 |
| Cb&F Groundworks Limited | Construction | 2022 |
| Cb&F Plumbing Heating and Bathrooms Ltd | Construction | 2024 |
| Cesare & Co Limited | Real estate | 2006 |
| Ceta Insurance Ltd | Financial services | 1993 |
| Ceta Software Limited | Information & communication | 1995 |
| Chameleon PDE Ltd | Education | 2020 |
| Change Audit Limited | Real estate | 2006 |
| Chase Cadogan Ltd | Extraterritorial | 2011 |
| Chase Financial Holdings Ltd | Professional & scientific | 2007 |
| Cherry Products Limited | Manufacturing | 1997 |
| Cherwell Land Development Company Limited(The) | Construction | 1954 |
| Cherwell Properties Limited | Real estate | 1963 |
| Cherwell Property Services Limited | Real estate | 2003 |
| Chidem Limited | Other services | 2012 |
| Chinnor Motors Limited | Wholesale & retail | 1986 |
| Chippy Flower Farm Limited | Extraterritorial | 2022 |
| Chit Chat Limited | Other services | 2020 |
| Chochin Limited | Financial services | 2025 |
| Christine O'Connell Consulting Ltd | Professional & scientific | 2017 |
| CHT Enterprises Limited | Hospitality | 2007 |
| Church Lane Joinery Limited | Manufacturing | 2004 |
| CIB Retail Limited | Wholesale & retail | 2001 |