| Autobahn Haus Ltd | Wholesale & retail | 2026 |
| Autoglide Ltd | Wholesale & retail | 2024 |
| Autograph Bookkeeping & Accountancy Limited | Professional & scientific | 2014 |
| Autograph Fair Trade Assoc (2013) Ltd | Other services | 2013 |
| Autokims Ltd | Information & communication | 2024 |
| Automatic Transmission Services Limited | Other services | 2010 |
| Automotive Auditors Limited | Professional & scientific | 2011 |
| Automotive Glazing Academy Limited | Education | 2022 |
| Autosmith Ltd | Wholesale & retail | 2012 |
| Autym Developments Limited | Construction | 2020 |
| AUZ3 Ltd | Real estate | 2023 |
| AV Training and Consultancy Ltd | Professional & scientific | 2026 |
| Avalon Bars & Events Limited | Hospitality | 2009 |
| Avalon Business Services Ltd | Administrative & support | 2014 |
| Avalon Luxe Cars Ltd | Wholesale & retail | 2017 |
| Avalon Ventures Holdings Ltd | Financial services | 2018 |
| Avalon Ventures Ltd | Administrative & support | 2018 |
| Avanti Gym Installations and Repairs Ltd | Manufacturing | 2026 |
| Avarin Advisory Ltd | Information & communication | 2026 |
| Avatarai United Kingdom Ltd | Information & communication | 2024 |
| Avellana Place (Colchester) Management Company Limited | Real estate | 2015 |
| Avenrise Properties Limited | Real estate | 1994 |
| Avensis International Commerce UK Limited | Wholesale & retail | 2022 |
| Aventi Electrical Ltd | Construction | 2024 |
| Avenue 88 Properties Ltd | Administrative & support | 2020 |
| AVI Commercial Holdings Limited | Administrative & support | 2013 |
| Avia BLU Flightline Limited | Transport & logistics | 1986 |
| Aviation Business Limited | Professional & scientific | 2015 |
| Aviation Business Publications Limited | Information & communication | 1996 |
| Aviation Covers Ltd | Manufacturing | 2024 |
| Avid Fire & Safety Ltd | Public administration | 2023 |
| Avid Landscapes Ltd | Administrative & support | 2025 |
| Avighna Estate Limited | Real estate | 2018 |
| Avin Consulting Ltd | Financial services | 2020 |
| Avita Properties Ltd | Real estate | 2019 |
| Avocet Place Management Company Limited | Real estate | 2017 |
| Avom Care Limited | Health & social care | 1999 |
| Avom Ltd | Health & social care | 2015 |
| AVR Services Ltd | Information & communication | 2025 |
| Avrm Management Company Limited | Households | 2021 |
| AVT Distribution Limited | Wholesale & retail | 2021 |
| Avvas Studio Ltd | Wholesale & retail | 2021 |
| AW Accounts Office Ltd | Professional & scientific | 2025 |
| AW Auto Locks Ltd | Wholesale & retail | 2024 |
| AW Invest Ltd | Real estate | 2019 |
| AWA Building Services Consultants Limited | Other services | 1997 |
| AWB Consulting Ltd | Professional & scientific | 2025 |
| AWF Electrical Engineers Ltd | Construction | 2026 |
| AWL Commercial GAS Limited | Energy | 2016 |
| AWM Consults Ltd | Professional & scientific | 2019 |
| AWS Construction Management Ltd | Construction | 2012 |
| Axcess Networks Ltd | Construction | 2019 |
| Axel Arty Ltd | Wholesale & retail | 2025 |
| AXI Foods Ltd | Hospitality | 2024 |
| Axial Holdings Limited | Real estate | 2025 |
| Axielmax Capital Limited | Financial services | 2025 |
| Axin Media Ltd | Information & communication | 2026 |
| Axis Accounting and Bookkeeping Ltd | Professional & scientific | 2005 |
| Axnar UK Ltd. | Wholesale & retail | 2020 |
| Ayat Mirza Ltd | Other services | 2019 |
| Aydin IBZ Investments Ltd | Real estate | 2025 |
| Ayling Building Services Ltd | Construction | 2018 |
| Aylott Construction Services Limited | Construction | 2010 |
| AYM Property Limited | Real estate | 2023 |
| AYS Care Ltd | Health & social care | 2022 |
| Ayten Ltd | Construction | 2026 |
| Ayur Medix Ltd | Health & social care | 2025 |
| Ayurveda Cures Ltd | Wholesale & retail | 2020 |
| Ayurveda World Ltd | Wholesale & retail | 2023 |
| Ayurvedicheritage Ltd | Other services | 2024 |
| Azcon Component Solutions Limited | Wholesale & retail | 2014 |
| Azcon CSL Limited | Wholesale & retail | 2009 |
| Azmi Transport Ltd | Transport & logistics | 2019 |
| Aztec IT Solutions Limited | Information & communication | 2011 |
| Aztek 1994 Limited | Extraterritorial | 2012 |
| B & D Partnership Ltd | Other services | 2022 |
| B & S Confectionery Limited | Wholesale & retail | 2004 |
| B & S Davies Printing Company Limited | Manufacturing | 1997 |
| B and C Educational Limited | Education | 2002 |
| B Anderson Consultancy Ltd | Wholesale & retail | 2023 |
| B Calm Ltd | Wholesale & retail | 2020 |
| B Clark Property Group Ltd | Real estate | 2026 |
| B Clark Vehicle Body Repairs Limited | Wholesale & retail | 2014 |
| B English Roofing & Sons Ltd | Construction | 2025 |
| B Executive Support Ltd | Administrative & support | 2026 |
| B H Concepts Limited | Professional & scientific | 1982 |
| B Home Sales Ltd | Construction | 2024 |
| B Independent Support Limited | Health & social care | 2023 |
| B Kitchen Limited | Hospitality | 2025 |
| B Pump Room Ltd | Real estate | 2026 |
| B Smart Repairs Limited | Wholesale & retail | 2005 |
| B UT Construction Company Ltd | Construction | 2024 |
| B Youngson Property and Lettings Limited | Real estate | 2017 |
| B&D Trading Collectibles Ltd | Wholesale & retail | 2026 |
| B&G Vapes Ltd | Wholesale & retail | 2018 |
| B&M Mart Limited | Wholesale & retail | 2026 |
| B&O Training Limited | Health & social care | 2018 |
| B&P Developers Limited | Construction | 2020 |
| B&S Contracts Limited | Construction | 2021 |
| B&S Installations Limited | Construction | 2007 |