| Boxgola Ltd | Manufacturing | 2022 |
| Boyle & Hooke Oxford Ltd | Administrative & support | 2018 |
| Boynat MED Ltd | Health & social care | 2015 |
| BPR North Ltd | Other services | 2025 |
| BR Motors Oxford Ltd | Wholesale & retail | 2024 |
| Bracco Horizons Limited | Professional & scientific | 2019 |
| Bracco UK Limited | Wholesale & retail | 2000 |
| Bradford LOW Carbon Hydrogen Limited | Administrative & support | 2022 |
| Bradford Securities Limited | Real estate | 1958 |
| Bradglade Limited | Real estate | 1992 |
| Bradley Employment Consulting Ltd | Professional & scientific | 2019 |
| Bradley Smith Racing Limited | Arts & recreation | 2004 |
| Bradshaws (Car Repairs) Ltd | Extraterritorial | 2015 |
| Brady Fabrications Limited | Professional & scientific | 1984 |
| Brainomix Limited | Information & communication | 2010 |
| Brainwaves and Blueprints Ltd | Professional & scientific | 2025 |
| Brakerman Property Management Limited | Real estate | 2017 |
| Bramble Verbiage CIC | Arts & recreation | 2014 |
| Brambleside Management Company (High Wycombe) Limited | Real estate | 1983 |
| Bramley Construction Limited | Construction | 2013 |
| Brammeier Limited | Professional & scientific | 2014 |
| Brand New Start Ltd | Education | 2009 |
| Brandbloom Ltd | Professional & scientific | 2022 |
| Branded Products Services Limited | Administrative & support | 2008 |
| Brandway Creative Ltd | Professional & scientific | 2026 |
| Branos Oxford Ltd | Hospitality | 2023 |
| Brasenose Limited | Construction | 1994 |
| Bratby Medical Ltd | Health & social care | 2020 |
| Braveheart Financial Services Limited | Extraterritorial | 2007 |
| Bravo Energy Ltd | Professional & scientific | 2022 |
| Brazilian Soccer Schools and Football Academies Limited | Arts & recreation | 1999 |
| BRC Scientific Ltd | Professional & scientific | 2023 |
| Bread Oxford Limited | Manufacturing | 2019 |
| Break OFF Capital LLP | | 2016 |
| Break OFF Mark I LLP | | 2016 |
| Break OFF Mark II LLP | | 2019 |
| Breamgale Limited | Administrative & support | 1983 |
| Breatheox Limited | Health & social care | 2017 |
| Breckon & Breckon (Asset Management & Consultancy) Limited | Real estate | 2009 |
| Breckon & Breckon (Letting & Management) Ltd | Real estate | 2003 |
| Breckon Commercial Estates Limited | Professional & scientific | 2011 |
| Bree&Dave Limited | Wholesale & retail | 2025 |
| Breken Properties Ltd | Construction | 2019 |
| Brentstar Holdings Limited | Professional & scientific | 2009 |
| Brew Oxford Ltd | Wholesale & retail | 2014 |
| Brew People Limited | Professional & scientific | 2021 |
| Brewhouse Yard (Wallingford) Management Company Limited | Households | 2024 |
| Brian Watts Partners Ltd | Households | 2012 |
| Briarwood 26 Limited | Real estate | 2026 |
| Briarwood Development 22 Limited | Construction | 2022 |
| Brick Kiln (UK) Limited | Manufacturing | 1998 |
| Bricks N Daughter Ltd | Extraterritorial | 2014 |
| Brickwood Investments & Holdings Limited | Construction | 2017 |
| Brics Bridge Ltd | Information & communication | 2025 |
| Bridge International Study Ltd | Education | 2012 |
| Bridge Street FH Limited | Real estate | 2025 |
| Bridge Street Mill (Witney) Management Company Limited | Households | 2004 |
| Bridge to Care Ltd | Health & social care | 2021 |
| Bridgegate Business Centre Management Company Ltd | Households | 2006 |
| Bridgelabs Ltd | Information & communication | 2025 |
| Bridgemark Education Limited | Financial services | 2020 |
| Bright App Enterprises Limited | Information & communication | 2021 |
| Bright Bonhomme Ltd | Real estate | 2020 |
| Bright Cleaning Services Oxford Ltd | Administrative & support | 2019 |
| Bright Lights Studio Ltd | Information & communication | 2023 |
| Bright Mile Transport Ltd | Transport & logistics | 2025 |
| Bright Planet Ltd | Professional & scientific | 2025 |
| Brightest Events Ltd | Extraterritorial | 2016 |
| Brightlight Support Ltd | Health & social care | 2021 |
| Brighton Marina Block F1 Ltd | Real estate | 2014 |
| Brighton Marina Block F2 Ltd | Extraterritorial | 2014 |
| Brit Auto Global Ltd | Wholesale & retail | 2025 |
| Britannia Blinds Limited | Manufacturing | 1989 |
| Britannia Property Agency Ltd | Hospitality | 2019 |
| Briten Choice UK Limited | Wholesale & retail | 2026 |
| Britgrowth Limited | Financial services | 2017 |
| British Archaeological Reports (Oxford) Limited | Information & communication | 1992 |
| British Democratic Alliance Ltd | Information & communication | 2025 |
| Britmark Trading Ltd | Wholesale & retail | 2025 |
| Britongates Ltd | Education | 2013 |
| Brittains,Limited | | 1890 |
| Brittains-Arborfield Limited | | 1903 |
| BRO & BRO Ltd | Real estate | 2025 |
| Broadcast Ltd | Professional & scientific | 2015 |
| Broadoakdata Ltd | Information & communication | 2017 |
| Broadsword International Limited | Wholesale & retail | 1998 |
| Broadway Cottages Chalgrove Management Company Limited | Households | 2011 |
| Brokai Ltd | Professional & scientific | 2024 |
| Broken MAN Music Ltd | Information & communication | 2025 |
| Bromlee Limited | Wholesale & retail | 2023 |
| Bromwest Limited | Financial services | 1954 |
| Bronte School and Nursery Limited | Education | 2013 |
| Bronzefast Limited | Professional & scientific | 2007 |
| Bronzeglass Limited | Professional & scientific | 2007 |
| Bronzekey Limited | Professional & scientific | 2007 |
| Bronzemain Limited | Professional & scientific | 2007 |
| Bronzepatch Limited | Professional & scientific | 2007 |
| Bronzepitch Limited | Professional & scientific | 2007 |
| Brookes Carpentry Ltd | Construction | 2006 |
| Brookes Event Management Ltd | Hospitality | 2024 |