| Axelerate Consulting Limited | Professional & scientific | 2016 |
| Axial Consultants Ltd | Information & communication | 2006 |
| Axios Capital Ltd | Real estate | 2026 |
| Axis Global Ltd | Information & communication | 2025 |
| AZ Automobiles Limited | Wholesale & retail | 2011 |
| Aztec Aviators Limited | Administrative & support | 2012 |
| Azurea Care Limited | Health & social care | 2023 |
| Azzurri Cambridge Limited | Hospitality | 2026 |
| Azzurri Hitchin Limited | Hospitality | 2026 |
| Azzurri Investments Limited | Financial services | 2020 |
| B & D Civil Engineers Ltd | Construction | 2017 |
| B & G Property Renovations Limited | Construction | 2012 |
| B & K Jackson Limited | Professional & scientific | 2013 |
| B and J Cutting Services Ltd | Administrative & support | 2021 |
| B Lawson Property Limited | Real estate | 2022 |
| B Natural Limited | Extraterritorial | 2011 |
| B&G Property Rentals Ltd | Real estate | 2024 |
| B&J Corporate Consulting Limited | Professional & scientific | 2023 |
| B&Wh Ltd | Real estate | 2020 |
| B' Smart DRY Cleaners Ltd | Other services | 1997 |
| B.S. Global Invest Limited | Financial services | 2017 |
| B2ME Tourism Marketing Limited | Administrative & support | 2009 |
| Babies: Birth and Baby Information, Education, Support CIC | Education | 2000 |
| Back 2 Schoolival C.I.C. | Arts & recreation | 2016 |
| Back Care Trading Limited | Wholesale & retail | 1999 |
| Backitup Limited | Information & communication | 2012 |
| Badget Limited | Professional & scientific | 2011 |
| Baggy Ltd | Construction | 2009 |
| Baird Chatfield Research & Strategy Ltd | Professional & scientific | 2020 |
| Baitul Qur’An Online Academy Ltd | Education | 2025 |
| Baker & Burke Caterers Ltd | Hospitality | 2026 |
| BAL & K Homes Ltd | Real estate | 2022 |
| Balance Recruitment Ltd | Administrative & support | 2007 |
| Balazymedia Limited | Information & communication | 2022 |
| Balco Brands Limited | Wholesale & retail | 2019 |
| Baldock Top Dogs Ltd | Professional & scientific | 2015 |
| Ballinger Equine Limited | Professional & scientific | 2017 |
| Balliol Management Limited | Households | 1994 |
| Bambuka Ltd. | Wholesale & retail | 2018 |
| Banana UK Media Ltd | Manufacturing | 2011 |
| Bancroft Dental Limited | Health & social care | 2008 |
| Baobab Horticulture and Design Limited | Administrative & support | 2021 |
| Barber Pro Ltd | Other services | 2025 |
| Barcroft Technology Limited | Information & communication | 2006 |
| Barker Parry Town Planning Limited | Professional & scientific | 2004 |
| Barking Vale Limited | Administrative & support | 2005 |
| BARN2YARN Limited | Manufacturing | 2018 |
| Barnet Park Homes Limited | Construction | 2020 |
| Barracuda Shop Fitting Limited | Construction | 2006 |
| Barrington Harvey Limited | Professional & scientific | 2025 |
| Bartlett & Johnston Lettings Ltd | Real estate | 2024 |
| Barton Moorhouse Ltd | Real estate | 2024 |
| Base Property Management Ltd | Construction | 2026 |
| BASE52 Ltd | Professional & scientific | 2003 |
| Basedata Business Intelligence Ltd | Information & communication | 2019 |
| Batch Fifty Two Limited | Hospitality | 2022 |
| Battcomms Limited | Information & communication | 2005 |
| Baxter's Holdings Limited | Financial services | 1942 |
| Bay Mining Consultants Limited | Mining & quarrying | 2012 |
| BB06 Consulting Limited | Administrative & support | 2020 |
| BBK Corporation Limited | Administrative & support | 2020 |
| BBR Design Services Limited | Professional & scientific | 2019 |
| BBS Bar Ltd | Hospitality | 2018 |
| BBS Building Services Limited | Construction | 2018 |
| BC Dynamics Ltd | Information & communication | 2022 |
| BC Worldwide Ltd | Wholesale & retail | 2017 |
| BDE Trading Limited | Wholesale & retail | 2026 |
| BE Abrasive Limited | Wholesale & retail | 2015 |
| Beacon Close (Management Company) Limited | Households | 2017 |
| Beacon Social Care Ltd | Health & social care | 2024 |
| Beam Construction Limited | Construction | 2011 |
| Beam Holdings Ltd | Real estate | 2021 |
| Bearton Court Residents Association Limited | Households | 1999 |
| Beastie Buddies Ltd | Administrative & support | 2024 |
| Beaulieu Property Holdings Limited | Construction | 2023 |
| Beauty at NO.10 Limited | Other services | 2024 |
| Bebe M T Limited | Other services | 2024 |
| Beckett Consultancy Limited | Other services | 2020 |
| Bedford Court Hitchin Limited | Real estate | 1975 |
| Bedfordshire Car Chargers Ltd | Extraterritorial | 2021 |
| Beds and Borders Gardening Company Limited | Administrative & support | 2026 |
| Beds Herts & Cambs Land Rover Club Limited | Arts & recreation | 2004 |
| Beds High Performance Self Drive Ltd | Administrative & support | 2026 |
| BEE 1ST Limited | Wholesale & retail | 2024 |
| Beebooks Limited | Financial services | 2019 |
| Beech Tree Management Ltd | Real estate | 2020 |
| Beechey Holdings Limited | Real estate | 2022 |
| Beechtopequerry Ltd | Real estate | 2021 |
| Beer Belly Hospitality Ltd | Hospitality | 2024 |
| Beer Passport Ltd | Wholesale & retail | 2019 |
| Behold.Ai Global Technologies Ltd | Information & communication | 2025 |
| Belfield Welding Limited | | 1979 |
| Belgravia Chase Estates Limited | Financial services | 2025 |
| Belief Dynamics Ltd | Other services | 2024 |
| Belitang Properties Limited | Real estate | 2024 |
| Bell Advisers Ltd | Professional & scientific | 2023 |
| Bellair Farms Jamaica Ltd | Wholesale & retail | 2021 |
| Bellegove Limited | Health & social care | 2023 |
| Bellemare Chartering Consultancy Ltd | Administrative & support | 2021 |
| Bellgove Properties Limited | Real estate | 2025 |