| Boost Media Limited | Information & communication | 2022 |
| Boostgrid Ltd | Information & communication | 2025 |
| Booterstown Group Ltd | Financial services | 2024 |
| Booth Tarmacadam Limited | Construction | 1975 |
| Boreasteel UK Limited | Wholesale & retail | 2016 |
| Boreva Staffing Solutions Limited | Administrative & support | 2023 |
| Born Artistic to Achieve Ltd | Arts & recreation | 2023 |
| Borough Homes Limited | Extraterritorial | 1998 |
| Borough Processing Ltd | Information & communication | 2023 |
| Bosmere Contracting Limited | Construction | 2020 |
| Bosmere Mill Limited | Real estate | 1996 |
| Boss Autos Ltd | Wholesale & retail | 2017 |
| Boss Chicken UK Ltd | Hospitality | 2025 |
| Boss Enclosures Limited | Extraterritorial | 2011 |
| Boss Media Limited | Professional & scientific | 2025 |
| Bosship Limited | Administrative & support | 2019 |
| Bought the Farm Limited | Information & communication | 2025 |
| Bougie Scents Ltd | Extraterritorial | 2020 |
| Boujee Renovation Ltd | Construction | 2023 |
| Boundary Oaks Management Company Ltd | Households | 2021 |
| Boundless Holidays Ltd | Administrative & support | 2020 |
| Bountiful Gardens Limited | Administrative & support | 2022 |
| Bouquet Garni Caterers Limited | Hospitality | 2001 |
| Bourne Garden Centre Ltd | Wholesale & retail | 2002 |
| Bournewood Park (Halstead) Management Company Limited | Households | 2026 |
| Bouw Consultancy Ltd | Professional & scientific | 2023 |
| Bowden & Brazil Ltd | Information & communication | 2018 |
| Bowers & Co Accountancy Ltd | Professional & scientific | 2019 |
| Bowls World Ltd | Wholesale & retail | 2003 |
| Bows and Arrows | Education | 2009 |
| Bowyer Close (Barham) Management Company Limited | Real estate | 2012 |
| Box Valley Architectural Design Limited | Professional & scientific | 2019 |
| Boxton Developments Limited | Construction | 2021 |
| Boxtree Game Supplies Limited | Agriculture & fishing | 2007 |
| Boyas Tech Services Ltd | Information & communication | 2026 |
| Boyle Developments Limited | Construction | 2021 |
| Boyten (Building and Property Maintenance) Limited | Wholesale & retail | 1990 |
| Bozhold Limited | Transport & logistics | 2008 |
| BP Electrical Services (EA) Ltd | Construction | 2020 |
| Braceforce Warehousing Limited | Professional & scientific | 1997 |
| Brad's Car Care Ltd | Wholesale & retail | 2026 |
| Brader & Harvey Ltd | Construction | 2010 |
| Bradley Building Contractors Limited | Construction | 2018 |
| Bradmanns Limited | Wholesale & retail | 2006 |
| Bradwell Lewis Properties and Developments Ltd | Construction | 2020 |
| Braemar Consulting Limited | Professional & scientific | 2025 |
| Braggons Trustees Limited | Professional & scientific | 2012 |
| Brain Stormer Ltd | Extraterritorial | 2025 |
| Brainwave Interactive Ltd | Information & communication | 2024 |
| Brajan Transporter Ltd | Transport & logistics | 2014 |
| Brambling Consulting Ltd | Information & communication | 2026 |
| Brambus Limited | Hospitality | 2019 |
| Brame Brickwork Ltd | Construction | 2019 |
| Bramford Chippy Ltd | Hospitality | 2025 |
| Bramford Gardening & Property Maintenance Ltd | Transport & logistics | 2010 |
| Bramford Gardens (Ipswich) Management Company Limited | Households | 2008 |
| Bramford Golf Centre Ltd | Arts & recreation | 2026 |
| Bramford Hand Car Wash Ltd | Other services | 2021 |
| Bramford Homes Limited | Real estate | 2013 |
| Bramford Road (Ipswich) Management Company Limited | Households | 2002 |
| Bramford Road Bakery Ltd | Hospitality | 2023 |
| Bramford Waterfront Cafe Limited | Hospitality | 2009 |
| Branbuild Ltd | Real estate | 2022 |
| Branded Garden Products Limited | Wholesale & retail | 1939 |
| Brandon Property Maintenance Specialists Ltd | Construction | 2025 |
| Brands Estore Limited | Wholesale & retail | 2024 |
| Brands Garage Limited | Wholesale & retail | 2003 |
| Brasov Ipswich Ltd | Wholesale & retail | 2024 |
| Brave Active Ltd | Wholesale & retail | 2024 |
| Brave Futures | Health & social care | 2012 |
| Bravo Print Limited | Manufacturing | 2011 |
| Bravo Theatre Arts Limited | Arts & recreation | 2015 |
| Brayborne Facilities Services Limited | Administrative & support | 1984 |
| Braysbuild Ltd | Construction | 2024 |
| BRC Residential Ltd | Construction | 2015 |
| BRC Welding & Fabrications Ltd | Manufacturing | 2019 |
| BRD MAX Ltd | Administrative & support | 2026 |
| Bread Bowl Limited | Hospitality | 2025 |
| Breadline Africa | Health & social care | 1998 |
| Breakspeare House Ltd | Real estate | 2025 |
| Breakthrough Fitness Limited | Arts & recreation | 2025 |
| Breast Friends CIC | Health & social care | 2022 |
| Bree's Decorating Ltd | Construction | 2019 |
| Breheny Group Limited | Construction | 2002 |
| Breheny Group Plant Limited | Administrative & support | 1975 |
| Brendon Utjita Limited | Construction | 2023 |
| Brentoak Investments Ltd | Real estate | 2015 |
| Brentoak Properties Limited | Real estate | 1983 |
| Brenton Rock Solutions Ltd | Financial services | 2018 |
| Brett Valley Builders Ltd | Construction | 2013 |
| Brett Valley Maintenance Services Limited | Administrative & support | 2002 |
| Brewer and Moss Ltd | Hospitality | 2015 |
| Breydon Way RTM Company Limited | Real estate | 2008 |
| BRH Recruiment Ltd | Administrative & support | 2025 |
| Briandaroe Limited | Real estate | 2019 |
| Briar Copywriting Ltd | Professional & scientific | 2011 |
| Briardale Orchard Maintenance Company Limited | Households | 1989 |
| Briarwood Furniture Limited | Construction | 2001 |
| Brick and Timber Limited | Real estate | 2021 |
| Brickfield Trades Ltd | Construction | 2025 |