| Birketts LLP | | 2006 |
| Birketts Secretaries Limited | Extraterritorial | 1990 |
| Birketts Solicitors Limited | Professional & scientific | 1988 |
| Birketts Trust Corporation Limited | Administrative & support | 2023 |
| Biryani HUT Ipswich Ltd | Hospitality | 2026 |
| Bishop Consultancy (UK) Limited | Information & communication | 2002 |
| Bishop Triathlon Limited | Arts & recreation | 2016 |
| Biskitchen Worldwide Limited | Hospitality | 2023 |
| Bist Limited | Professional & scientific | 2021 |
| Bist Services Ltd | Construction | 2025 |
| BIT More Media Limited | Information & communication | 2015 |
| Bitcon Surfacing Limited | Construction | 2014 |
| Bitumen Flat Roofing Association | Other services | 2024 |
| Bitwen Ltd | Other services | 2022 |
| Bitz N Bobz Ltd | Wholesale & retail | 2025 |
| Bixley Pharma Limited | Wholesale & retail | 2008 |
| BIZ Guru Limited | Information & communication | 2008 |
| BIZIT4ALL Limited | Information & communication | 2009 |
| Bizsyscon Ltd | Information & communication | 2017 |
| BJA Roofing Ltd | Construction | 2015 |
| BJB 2025 Ltd | Transport & logistics | 2025 |
| BJK Entertainment Limited | Arts & recreation | 2017 |
| Bjorn Trading Ltd | Financial services | 2025 |
| BK Garcia Consultancy Limited | Professional & scientific | 2014 |
| BK Livings Ltd | Real estate | 2026 |
| Bkairali Ltd | Health & social care | 2020 |
| BKB1 Ltd | Real estate | 2022 |
| Bkhd Ltd | Real estate | 2025 |
| BKR Construction (Essex) Limited | Construction | 2011 |
| BKT Transport Ltd | Transport & logistics | 2026 |
| Bl.Ez Holdings Ltd | Wholesale & retail | 2021 |
| Black and Blue Rowing Limited | Arts & recreation | 2009 |
| Black Barbary Lion Ltd | Wholesale & retail | 2024 |
| Black Skip Machinery Ltd | Manufacturing | 2024 |
| Black Stag Styling Ltd | Wholesale & retail | 2018 |
| Black Star Books Limited | Extraterritorial | 2019 |
| Black Swan Developments East Anglia Ltd | Construction | 2012 |
| Black Venture Capital Ltd | Financial services | 2018 |
| Blackbot Developments Limited | Wholesale & retail | 2025 |
| Blackdg Limited | Professional & scientific | 2020 |
| Blacksmiths Way (Laxfield) Management Company Limited | Households | 2022 |
| Blackstock Grange (Campsea Ashe) Residents Management Company Limited | Households | 2012 |
| Blackstone Consulting Ipswich Ltd | Information & communication | 2025 |
| Blackstone Hair Limited | Other services | 2021 |
| Blackwater Products Ltd | Wholesale & retail | 2023 |
| Blackwell Academy LLP | | 2016 |
| Blackwell Fitness Limited | Arts & recreation | 2008 |
| Blackwood Bay Ltd | Other services | 2025 |
| Bladen Consultancy Limited | Administrative & support | 2022 |
| Bladen Investments Limited | Financial services | 2022 |
| Blades Pest Solutions Ltd | Administrative & support | 2024 |
| Blake Heating & Property Services Ltd | Construction | 2018 |
| Blake Mayhew Limited | Real estate | 2010 |
| Blake Terry Holdings Ltd | Financial services | 2020 |
| Blanche Park Consulting Limited | Professional & scientific | 2024 |
| Blankbox Technologies Ltd | Information & communication | 2023 |
| Blaylock UK Limited | Professional & scientific | 2021 |
| Blazing Barrell Smokeworks Ltd | Financial services | 2024 |
| Blckout Ltd | Professional & scientific | 2023 |
| BLD Construction Suffolk Ltd | Construction | 2025 |
| BLD Homes Ltd | Real estate | 2025 |
| Blends Hospitality Ltd | Hospitality | 2026 |
| Blenheim Construction Services Limited | Construction | 2019 |
| Blessed Hope Enterprises Limited | Wholesale & retail | 2012 |
| Bletta Services Limited | Professional & scientific | 2023 |
| Blinkbotai Ltd | Information & communication | 2025 |
| Blissbalance Wellness Ltd | Extraterritorial | 2026 |
| Blizanic (UK) Limited | Wholesale & retail | 2021 |
| Blockley Court Management Company Limited | Real estate | 1992 |
| Blois Properties Limited | Real estate | 2018 |
| Bloom Eatery Ltd | Hospitality | 2024 |
| Bloom Global Trading Ltd | Wholesale & retail | 2025 |
| Bloom Lounge Ltd | Hospitality | 2024 |
| Bloom Theory Ltd | Wholesale & retail | 2026 |
| Bloom Yoga & Wellbeing Ltd | Arts & recreation | 2025 |
| Bloom'N'Skin Medical Aesthetics Limited | Health & social care | 2019 |
| Bloome Construction Ltd | Construction | 2016 |
| Bloome Investments Ltd | Professional & scientific | 2017 |
| Bloomfield Electrical Ltd | Construction | 2021 |
| Blooming and Blissful Spa Ltd | Other services | 2026 |
| Blooming Balance Limited | Information & communication | 2009 |
| Blooms Birds Limited | Agriculture & fishing | 2008 |
| Blossoms Trading Limited | Health & social care | 2017 |
| Blouberg Packing Solutions Ltd | Administrative & support | 2026 |
| BLT Direct Limited | Other services | 2004 |
| Blue 68 Ltd | Administrative & support | 2011 |
| Blue and Red Hear Clear Ltd | Wholesale & retail | 2022 |
| Blue Bard Holdings Ltd | Financial services | 2026 |
| Blue Bazaar Ltd | Wholesale & retail | 2024 |
| Blue Beyond Books Limited | Information & communication | 2015 |
| Blue Button Legal Indemnities Ltd | Financial services | 2016 |
| Blue Carpet Management Limited | Arts & recreation | 2015 |
| Blue Flame Abbott Ltd | Real estate | 2015 |
| Blue Flame Properties Limited | Real estate | 2000 |
| Blue Fusion Ltd | Professional & scientific | 2026 |
| Blue Haven Care Limited | Health & social care | 2018 |
| Blue Hexagon Ltd | Professional & scientific | 2023 |
| Blue Kingfisher Limited | Real estate | 2018 |
| Blue Light Exterior Cleaning Ltd | Administrative & support | 2019 |
| Blue Light Windows Ltd | Construction | 2021 |