| Aytac Property Ltd | Real estate | 2026 |
| Azdex Labs Ltd | Wholesale & retail | 2025 |
| Azkaar Ltd | Wholesale & retail | 2024 |
| Azta Consulting Ltd | Information & communication | 2017 |
| Azuria UK Holdings Limited | Professional & scientific | 2019 |
| B & I Logistics Ltd | Transport & logistics | 2020 |
| B Brogan Limited | Construction | 2014 |
| B Gorgeous Ltd | Other services | 2025 |
| B Jewellery Ltd | Wholesale & retail | 2020 |
| B Jones & Daughters Ltd | Transport & logistics | 2020 |
| B Warwick Brickwork Limited | Construction | 2019 |
| B X Diner Limited | Hospitality | 2021 |
| B Y G Investments Limited | Financial services | 2018 |
| B&B Windows & Metalwork Ltd | Construction | 2011 |
| B.H.Brawn & Co.Limited | Manufacturing | 1957 |
| B.K Stud Ltd | Wholesale & retail | 2025 |
| B.L. Pneumatics Limited | Wholesale & retail | 1975 |
| B.W. Racing Limited | Real estate | 2003 |
| Baadal Accountancy Ltd | Information & communication | 2022 |
| Babybliss Limited | Arts & recreation | 2008 |
| Bagel BOB Ltd | Hospitality | 2024 |
| Bailey and Sons (Plumbers) Limited | Construction | 1959 |
| Bailey Murphy Holdings Ltd | Real estate | 2025 |
| Bailey Murphy Properties Ltd | Real estate | 2025 |
| Bailey Murphy Properties SPV1 Ltd | Real estate | 2025 |
| Bailey's Travel Limited | Administrative & support | 1998 |
| Baiman Construction Ltd | Construction | 2024 |
| Bains Co (Northants) Limited | Administrative & support | 2022 |
| Baird CNC Limited | Manufacturing | 2018 |
| BAK UP CIC | Information & communication | 2020 |
| Balantib Ltd | Transport & logistics | 2015 |
| Baleine Consulting Limited | Professional & scientific | 2026 |
| Ballard IT Services Limited | Administrative & support | 2014 |
| Balvoi Ltd | Transport & logistics | 2024 |
| Banana Estates Ltd | Information & communication | 2019 |
| BANDREI91 Ltd | Transport & logistics | 2021 |
| Baramft Limited | Wholesale & retail | 2026 |
| Barleys Warehouse Limited | Wholesale & retail | 1989 |
| Barnabas Trust Limited | Hospitality | 1978 |
| Barrington Lamont & Associates Ltd | Professional & scientific | 2024 |
| Barritt C.S. Ltd | Construction | 2002 |
| Barry Thomas News Ltd | Wholesale & retail | 2021 |
| Barton Energy Ltd | Transport & logistics | 2023 |
| Barton Petroleum (Holdings) Limited | Transport & logistics | 2004 |
| Barton Petroleum Limited | Transport & logistics | 1944 |
| Baruk Concepts Ltd | Wholesale & retail | 2015 |
| Basia Transport Ltd | Transport & logistics | 2024 |
| Basics Heating Ltd | Professional & scientific | 2016 |
| Basilico Kitchens Limited | Professional & scientific | 2021 |
| Basilico Limited | Hospitality | 1998 |
| Basilico Properties Limited | Real estate | 2021 |
| Bassetform Limited | Construction | 1998 |
| Battery Pack UK Ltd | Wholesale & retail | 2018 |
| Baulogic UK Ltd | Information & communication | 2019 |
| Baxell Ltd | Health & social care | 2013 |
| Bay Farm Power Limited | Energy | 2013 |
| BBE Training Ltd | Education | 2012 |
| Bbwg Services Ltd | Construction | 2025 |
| Bclifts Ltd | Construction | 2024 |
| BE Clean Commercial Limited | Administrative & support | 2023 |
| BE Inspired Holdings Ltd | Wholesale & retail | 2023 |
| BE Your Unique Ltd | Health & social care | 2026 |
| Be-Inventive Limited | Professional & scientific | 2006 |
| Beacon Water Treatments Holdings Limited | Financial services | 2025 |
| Bean Craft Roasters Limited | Manufacturing | 2025 |
| Beaty Farms Holdings Limited | Financial services | 2020 |
| Beauty Cabin Artistry Ltd | Other services | 2024 |
| Beauty Corner Ltd | Other services | 2023 |
| Beauty Panache Ltd | Wholesale & retail | 2026 |
| Beautybysara Ltd | Other services | 2019 |
| Beauzead Ltd | Professional & scientific | 2025 |
| Becks Homecare Services Limited | Health & social care | 2018 |
| BED & Suites Limited | Wholesale & retail | 2003 |
| Bedlam Enterprises Ltd | Hospitality | 2017 |
| Bednarz Logistic Ltd | Transport & logistics | 2023 |
| BEE Fire Ltd | Wholesale & retail | 2018 |
| BEE Friendly Limited | Wholesale & retail | 2018 |
| BEE Social Marketing Ltd | Information & communication | 2020 |
| Beechtree Landscaping Limited | Administrative & support | 2014 |
| Beedham Properties Limited | Real estate | 2016 |
| Beezy World Limited | Extraterritorial | 2022 |
| Belamey Ltd | Hospitality | 2022 |
| Believe Lettings Ltd | Real estate | 2020 |
| Belkin Limited | Manufacturing | 1996 |
| Bella Barista Ltd | Manufacturing | 1988 |
| Bellcar Limited | Professional & scientific | 2017 |
| Belle Casa (East Anglia) Limited | Households | 2015 |
| Belle Casa (UK) Limited | Transport & logistics | 2011 |
| Bellview Scaffolding Ltd | Construction | 2019 |
| Bellway Close Management Company Limited | Households | 2005 |
| BEM Transport Ltd | Transport & logistics | 2025 |
| BEN 2 Ltd | Health & social care | 2023 |
| Bendis Farm Ltd | Agriculture & fishing | 2026 |
| Benita Ajyiman Luxury Suites Ltd | Other services | 2025 |
| Benjamin Franklin Brewery Ltd | Manufacturing | 2020 |
| Bentley Court (Wellingborough) Limited | Real estate | 1989 |
| Bentley Wells Limited | Wholesale & retail | 2005 |
| Berdenela Ltd | Hospitality | 2024 |
| Berenyi Ltd | Transport & logistics | 2018 |
| Berry Close Management Company Limited | Households | 2022 |