| Athina PR Limited | Professional & scientific | 2012 |
| Athzaar Limited | Health & social care | 2024 |
| Aticus Law Ltd | Professional & scientific | 2012 |
| Atlas Corporate Finance Limited | Professional & scientific | 2012 |
| Atlas Laboratories Ltd | Health & social care | 2023 |
| Atma Consulting Services Limited | Financial services | 2024 |
| Atom LAB Tech Ltd | Wholesale & retail | 2025 |
| Atom Ology Ltd | Wholesale & retail | 2025 |
| Atomic Trading Group Ltd | Wholesale & retail | 2022 |
| Atoro 18 Limited | Other services | 2023 |
| Attachment Concerns Ltd | Health & social care | 2024 |
| Atticus Enterprises Ltd | Administrative & support | 2010 |
| ATX Properties Limited | Real estate | 2025 |
| August 2022 Limited | Health & social care | 2022 |
| Aura Investment Services Limited | Real estate | 2024 |
| Aura Technical Services Limited | Construction | 2014 |
| Aureous Ltd | Wholesale & retail | 2022 |
| Aus-Bore Build Limited | Construction | 1995 |
| Aus-Bore Estates Holdings Limited | Administrative & support | 2019 |
| Aus-Bore Estates Limited | Construction | 1995 |
| Aus-Bore Holdings Limited | Construction | 1997 |
| Aus-Bore Legal Ltd | Real estate | 2012 |
| Austin Informatics Ltd | Information & communication | 2016 |
| Australia Post Global Ecommerce Solutions (UK) Limited | Transport & logistics | 2016 |
| Auto Finance Online Limited | Financial services | 2015 |
| Auto Fusion Trader Limited | Wholesale & retail | 2025 |
| Automation & Controls Limited | Information & communication | 2025 |
| Automation ENG Limited | Professional & scientific | 2023 |
| Autumn Dreams Ltd | Manufacturing | 2025 |
| Autumns END Limited | Professional & scientific | 2022 |
| Auxilian Ltd | Other services | 2018 |
| Ava-V Limited | Professional & scientific | 2024 |
| Avace Clinic Limited | Health & social care | 2011 |
| Avalon (Europe) Limited | Other services | 1999 |
| Avalon Analytics Limited | Administrative & support | 2019 |
| Avant Garde Distribution Limited | Administrative & support | 2005 |
| AVG Investments Limited | Real estate | 2021 |
| AVG Medical Services Ltd | Health & social care | 2015 |
| Avicenna Medical Estates Limited | Health & social care | 2011 |
| AVO Consulting Limited | Construction | 2025 |
| AVO Mechanical Limited | Construction | 2021 |
| AW Investments 2023 Limited | Financial services | 2023 |
| AWD Building Limited | Construction | 2022 |
| AWS Capital Partners Ltd | Professional & scientific | 2026 |
| AX Property Group UK Limited | Real estate | 2025 |
| Axentia Biotech Limited | Information & communication | 2023 |
| Axentia Consulting Ltd | Professional & scientific | 2022 |
| Axiom Vision Ltd | Education | 2024 |
| Axipro Ltd | Wholesale & retail | 2025 |
| Axis Property Rentals Ltd | Real estate | 2025 |
| AXL Holdings Ltd | Financial services | 2026 |
| AXL Labs Ltd | Information & communication | 2026 |
| Ayakoo Limited | Information & communication | 2025 |
| Ayursavvyveda Limited | Wholesale & retail | 2016 |
| AZC Allergy Limited | Health & social care | 2025 |
| Aztekee Ltd | Wholesale & retail | 2019 |
| B & Combes LLP | | 2019 |
| B Chew Limited | Health & social care | 2014 |
| B D I Group Ltd | Professional & scientific | 1998 |
| B L Shipping (Holdings) Limited | Financial services | 2017 |
| B Moriarty Limited | Health & social care | 2010 |
| B Siddique Ltd | Health & social care | 2015 |
| B&A Medical Limited | Health & social care | 2019 |
| B&S Controls Limited | Professional & scientific | 2013 |
| B2B Product Consultancy Ltd | Professional & scientific | 2025 |
| BA Group Topco Limited | Financial services | 2025 |
| BAD Bitch Limited | Arts & recreation | 2024 |
| Badger Construction (Bury) Limited | Construction | 1974 |
| Bagdas Accounting and Management Consultancy Service Ltd | Professional & scientific | 2020 |
| Baggia Ltd | Hospitality | 2012 |
| Bail's Next GEN Limited | Real estate | 2025 |
| Bailey Dyson International Consultants Ltd | Other services | 2014 |
| Baileys of Alnwick Limited | Hospitality | 2009 |
| Bakesense Limited | Professional & scientific | 2010 |
| Balance Wilmslow Ltd | Arts & recreation | 2024 |
| Ball Ainsdale Limited | Professional & scientific | 2013 |
| Ballantine Recruitment Limited | Administrative & support | 2025 |
| Ballyalton Holdings Limited | Financial services | 2018 |
| Bamboo Brands Ltd | Wholesale & retail | 2022 |
| Bamboo Capital Limited | Extraterritorial | 2016 |
| Bamford Business Park Management Limited | Real estate | 1991 |
| Banks & Lloyd (Shipping) Limited | Transport & logistics | 1995 |
| Bankside Court (Heaton Mersey) RTM Company Ltd. | Households | 2019 |
| Bansal Eyecare Ltd | Health & social care | 2015 |
| Barakah 7 Ltd | Health & social care | 2014 |
| Barber-Brown Strategic Consulting Limited | Professional & scientific | 2016 |
| Bardill Digital Limited | Professional & scientific | 2022 |
| Bare Face Beauty Limited | Other services | 2015 |
| Baresi & Caine Ltd | Manufacturing | 2020 |
| Bargain World Cheshire Limited | Wholesale & retail | 2020 |
| Barker Financial Solutions Limited | Administrative & support | 2005 |
| Barlow Orthopaedics Ltd | Health & social care | 2024 |
| Barratt Electrical Limited | Construction | 2015 |
| Barratt Energy Group Limited | Financial services | 2011 |
| Barratt Energy Holding Limited | Financial services | 2013 |
| Barratt Energy Installations & Maintenance Limited | Construction | 2011 |
| Barratt Energy Limited | Professional & scientific | 2011 |
| Barratt Energy Power & Utility Services Limited | Construction | 2013 |
| Barratt Energy Solutions Ltd | Extraterritorial | 2016 |
| Bartle Meadows (Cottam) Management Company Limited | Households | 2016 |