| Besa Electrical Services Ltd | Construction | 2021 |
| Besa Properties Ltd | Real estate | 2023 |
| Bespoke Ready Solutions Limited | Wholesale & retail | 2022 |
| Bespoke Real Estate Services Ltd | Real estate | 2025 |
| Bespoke Resin Finishes Ltd | Construction | 2025 |
| Bespoke Skin Clinic Ltd | Other services | 2020 |
| Bespoke Tax Advisory Ltd | Professional & scientific | 2025 |
| Bespoke Utilities Ltd | Professional & scientific | 2012 |
| Bespoke Visa Solutions Limited | Professional & scientific | 2025 |
| Best Cleaners Ltd | Administrative & support | 2023 |
| Best FIX Roofing Solutions Ltd | Construction | 2024 |
| Best FM Consulting Ltd | Professional & scientific | 2021 |
| Best Home Control Ltd | Construction | 2017 |
| Best Kebab Van Ltd | Hospitality | 2026 |
| Best Nicholas Construction Ltd | Construction | 2016 |
| Bestzone Limited | Construction | 2001 |
| Betson Ltd | Arts & recreation | 2017 |
| Better Than the Pest Ltd | Administrative & support | 2023 |
| Betus Limited | Administrative & support | 2017 |
| Beverly Securities Limited | Professional & scientific | 1983 |
| Beweaders Properties Limited | Real estate | 2024 |
| Beyond the Chaos Ltd | Administrative & support | 2022 |
| BGM Advisors Ltd | Professional & scientific | 2021 |
| BGU Media Ltd | Information & communication | 2021 |
| Bhiindi X Limited | Extraterritorial | 2019 |
| Bhik Kotecha Ltd | Health & social care | 2010 |
| Bibi Docker Properties Limited | Real estate | 2016 |
| Bibi Real Estate Ltd | Real estate | 2022 |
| Bibolini & Co (Finance) Limited | Financial services | 2013 |
| Bibolini & Co Limited | Real estate | 2009 |
| Bientry Ltd | Information & communication | 2017 |
| Big BOY Empire Ltd | Arts & recreation | 2022 |
| Big Construction Limited | Construction | 2012 |
| Big NOW Limited | Wholesale & retail | 2025 |
| Billet Land Two Limited | Construction | 2020 |
| Bimex Engineers UK Ltd | Professional & scientific | 2025 |
| Binder Consultancy Ltd | Professional & scientific | 2024 |
| Birch & Hayer Ltd | Wholesale & retail | 2018 |
| Birchwood Properties Limited | Construction | 2003 |
| Biriyani Center Ilford Ltd | Wholesale & retail | 2025 |
| Birks Building Services Limited | Construction | 1999 |
| Bishop Waste Management Limited | Water & waste | 2020 |
| Bishops Stortford Developments Ltd | Real estate | 2017 |
| Bisi Investments Limited | Construction | 2020 |
| Bisset Holdings Ltd | Professional & scientific | 2019 |
| Bitnautic UK Ltd | Transport & logistics | 2020 |
| Bizim Evimiz Limited | Real estate | 2021 |
| Bizsphere 360 Ltd | Professional & scientific | 2025 |
| Bizworks International Limited | Professional & scientific | 2025 |
| BK IT Technology Ltd | Information & communication | 2018 |
| BKE Enterprise Ltd | Administrative & support | 2023 |
| BKN Platinum Ltd | Wholesale & retail | 2025 |
| Blac Opal Lounge Ltd | Health & social care | 2025 |
| Black Bear Creative Ltd | Professional & scientific | 2017 |
| Black Sheep Shepherd Huts Ltd | Manufacturing | 2018 |
| Black Taxi Hire Ltd | Transport & logistics | 2025 |
| Black Widow Security Solutions Limited | Administrative & support | 2024 |
| Blackstar Investments Limited | Real estate | 2020 |
| Blackstone Group Ltd | Real estate | 2022 |
| Blackwood Real Estate Ltd | Real estate | 2024 |
| Blade Craft Ltd | Other services | 2023 |
| Blaeberry Residents Company Limited | Households | 1989 |
| Blakemor Ltd | Construction | 2016 |
| Blanchard Legal Services Limited | Professional & scientific | 2025 |
| Blenheim Court (Woodford Green) Limited | Households | 1991 |
| Blitz IT Limited | Administrative & support | 2001 |
| Block D Jack Clow Road (Freehold) Limited | Other services | 2017 |
| Blockchain Bulls Limited | Administrative & support | 2020 |
| Blocx Matrix Limited | Construction | 2020 |
| BLU Sky Studios Ltd | Manufacturing | 2026 |
| Blucatin Associates Ltd | Hospitality | 2012 |
| Blue & Green Enterprises Limited | Administrative & support | 2018 |
| Blue Ichor Limited | Real estate | 2019 |
| Blue Sky ADR Limited | Professional & scientific | 2012 |
| Bluebell (Loughton) Estates Limited | Real estate | 2026 |
| Bluecroft Riverdale LLP | | 2013 |
| Bluespot Homecare Contractor Limited | Public administration | 2021 |
| Blurton Road Management Company Limited | Households | 2018 |
| BM Enforcement Limited | Administrative & support | 2016 |
| BM Internet (Management) Limited | Information & communication | 2019 |
| BM Internet LLP | | 2024 |
| BM Partners Limited | Households | 2017 |
| BMB Survey Ltd | Professional & scientific | 2012 |
| Bmtc Property and Buidling Ltd | Construction | 2026 |
| Bnifty Ltd | Wholesale & retail | 2017 |
| BOB Kirkland Steeplejacks Limited | Construction | 2015 |
| Bobcat TV Ltd | Information & communication | 2012 |
| Bobser Limited | Construction | 2026 |
| Boiera Developments Ltd | Real estate | 2026 |
| Boira Consultants Limited | Professional & scientific | 2024 |
| Bolab Concepts Limited | Real estate | 2024 |
| Bold & Beautiful Ltd | Other services | 2023 |
| Bold Minds Media Ltd | Professional & scientific | 2024 |
| Boldbridge Capital Limited | Construction | 2024 |
| Bollyhush Sekal Limited | Financial services | 2021 |
| Bombay Street Developments Ltd | Real estate | 2016 |
| Bomm Homes Ltd | Real estate | 2024 |
| Bond Landscape Design Limited | Construction | 2016 |
| Bono Homes Ltd | Real estate | 2020 |
| BOO Hewerdine Music Ltd | Arts & recreation | 2014 |