| AUS Group Limited | Financial services | 2023 |
| Austin & Bones Law Ltd | Professional & scientific | 2025 |
| Austin, Wolstencroft & Co. Limited | Manufacturing | 1954 |
| Authentically Audhd CIC | Education | 2026 |
| Autique Limited | Wholesale & retail | 2026 |
| Autism World CIC | Other services | 2024 |
| Auto Body Solutions Group Ltd | Wholesale & retail | 2018 |
| Auto Electronics Repairs Ltd | Other services | 2025 |
| Auto Elite Valeting Ltd | Administrative & support | 2022 |
| Auto Mats (Europe) Ltd | Wholesale & retail | 2025 |
| Auto PAL Limited | Wholesale & retail | 2019 |
| Auto Stop Motoring Limited | Wholesale & retail | 2016 |
| Auto Valets (Leeds) Limited | Administrative & support | 2018 |
| Auto-Serve Car Sales Ltd | Wholesale & retail | 2022 |
| Auto-Serve Oldham Ltd | Wholesale & retail | 2018 |
| Autoaura Ltd | Wholesale & retail | 2025 |
| Autoclaims Hire Recovery & Storage Ltd | Transport & logistics | 2024 |
| Autoclaims Solutions Ltd | Professional & scientific | 2017 |
| Autoeight Ltd | Information & communication | 2024 |
| Autoever Limited | Wholesale & retail | 2019 |
| Automaster Repair Centre Ltd | Wholesale & retail | 2023 |
| Automotive Marketplaces Ltd | Information & communication | 2024 |
| Automotive Parts Northwest Ltd | Wholesale & retail | 2024 |
| Autonel Ltd | Information & communication | 2025 |
| Autoplex Diagnostic and Repairs Ltd | Wholesale & retail | 2026 |
| Autoprofes Ltd | Wholesale & retail | 2017 |
| Autostream Logistics Ltd | Administrative & support | 2025 |
| Autotech Llanrwst Ltd | Wholesale & retail | 2026 |
| AUTOTEILE-MILLER24 Ltd. | Administrative & support | 2013 |
| Autowatt Ltd | Professional & scientific | 2025 |
| AV Auto Experts Ltd | Wholesale & retail | 2023 |
| AV Warranties Limited | Administrative & support | 2023 |
| Available Energy Ltd. | Construction | 2013 |
| Avalon Developments (Royton) Limited | Manufacturing | 2016 |
| Avani UN Limited | Wholesale & retail | 2025 |
| Avant-Green Express Services and Properties Limited | Construction | 2025 |
| Avanti Business Solutions Limited | Professional & scientific | 2010 |
| Avanti Commercial Limited | Wholesale & retail | 2026 |
| Avanti Gold Properties Ltd | Real estate | 2025 |
| Avantshield Limited | Real estate | 2006 |
| Avarlo Consultants Ltd | Professional & scientific | 2026 |
| Avaunt Group Limited | Professional & scientific | 2017 |
| Avela Ltd | Information & communication | 2026 |
| Avella People Ltd | Administrative & support | 2026 |
| Avencha Ltd | Information & communication | 2021 |
| Aventra Investments Ltd | Real estate | 2025 |
| Averia Ltd. | Administrative & support | 2009 |
| Averlade Limited | Manufacturing | 2024 |
| Averna Technical Ltd | Construction | 2022 |
| Averywell Limited | Professional & scientific | 2023 |
| Avisa Professional Services Ltd | Administrative & support | 2010 |
| Avondale Finance Ltd | Administrative & support | 2022 |
| Avro Community Football Club Limited | Arts & recreation | 2023 |
| Avro FC First Team Limited | Arts & recreation | 2023 |
| Avro Public House Limited | Hospitality | 2022 |
| Avscarenw Ltd | Health & social care | 2025 |
| AW Locums Limited | Professional & scientific | 2023 |
| AW Motors Ltd | Wholesale & retail | 2024 |
| AW Salvage Limited | Wholesale & retail | 2021 |
| AWA Manchester Ltd | Transport & logistics | 2025 |
| Awaan Services Limited | Transport & logistics | 2017 |
| Awais Trading Ltd | Wholesale & retail | 2025 |
| Awaly Properties Ltd | Real estate | 2022 |
| Awan Holdings Ltd | Financial services | 2023 |
| Awan Proprty Group Ltd | Real estate | 2026 |
| Away WE Spray MCR Ltd | Construction | 2023 |
| AWC Windows and Home Improvements Ltd | Construction | 2021 |
| Awkdiagnostics Limited | Public administration | 2021 |
| Awot Ltd | Health & social care | 2025 |
| AWS Project Group Ltd | Construction | 2025 |
| AWS Trading Ltd | Wholesale & retail | 2017 |
| Axel Laith Developments Ltd | Real estate | 2024 |
| Axiom Imaging Ltd | Health & social care | 2026 |
| Axis Publications Limited | Information & communication | 2002 |
| Axob Ltd | Professional & scientific | 2020 |
| Axtella Developments Limited | Administrative & support | 2016 |
| AY Partners Ltd | Real estate | 2024 |
| Ayaan Enterprises Ltd | Real estate | 2019 |
| Ayaan Holding Group Limited | Financial services | 2025 |
| Ayaan Housing Ltd | Real estate | 2022 |
| Ayaan Jewellers Ltd | Wholesale & retail | 2026 |
| Ayaan Property Management Ltd | Real estate | 2014 |
| Ayaan Realty UK Limited | Real estate | 2025 |
| Ayaan Saab Residency Ltd | Real estate | 2024 |
| Ayaans Express Limited | Hospitality | 2025 |
| Ayah Services Limited | Health & social care | 2025 |
| Ayan Travels and Tours Ltd | Administrative & support | 2019 |
| Aydin Properties Ltd | Real estate | 2023 |
| Ayesha Catering Ltd | Hospitality | 2024 |
| Ayesha Sweet Centre Ltd | Hospitality | 2023 |
| Ayesha,S Global Limited | Wholesale & retail | 2025 |
| Aygtrading Ltd | Wholesale & retail | 2021 |
| Aykiz Properties Ltd | Real estate | 2025 |
| Ayla Health Care Ltd | Health & social care | 2022 |
| Aylward Town Planning Limited | Professional & scientific | 2013 |
| AYM Oldham Ltd | Wholesale & retail | 2025 |
| AYN Investments Ltd | Real estate | 2021 |
| Ayra Fashion Boutique Ltd | Wholesale & retail | 2019 |
| Ayrton Senna Motors Limited | Wholesale & retail | 2023 |
| Ayrton Taylor Fitness Ltd | Arts & recreation | 2022 |