| Alaso OKE Estates Limited | Real estate | 2026 |
| Alaso OKE Ltd | Health & social care | 2025 |
| Alesbrook & Sowley Properties Ltd | Real estate | 2018 |
| Alex Mooneyen Services Limited | Administrative & support | 2025 |
| Alex Trans ALX Limited | Transport & logistics | 2019 |
| Alex&Giufu Ltd | Transport & logistics | 2024 |
| Alexstefl Ltd | Transport & logistics | 2023 |
| ALF Building Services Ltd | Construction | 2022 |
| Alice Lisbeth Ltd | Professional & scientific | 2013 |
| Alie Street LLP | | 2010 |
| ALIEN8 Supplements Ltd | Wholesale & retail | 2026 |
| ALL About Cash Ltd | Extraterritorial | 2013 |
| ALL Access Scaffolding Midlands Limited | Construction | 2015 |
| ALL Solutions (Leics) Ltd. | Construction | 2018 |
| Alpha Asset Holdings (UK) Ltd | Construction | 2023 |
| AM Coalville Ltd | Hospitality | 2022 |
| AM Recruitment Solution Ltd | Administrative & support | 2025 |
| AM Software Services Ltd | Information & communication | 2023 |
| Amaford Solutions Ltd | Wholesale & retail | 2003 |
| Amanda Lynn Law Limited | Professional & scientific | 2022 |
| Ambrose Builders Limited | Professional & scientific | 1975 |
| AMC Quarry Services Ltd | Construction | 2024 |
| Amhconsulting Limited | Professional & scientific | 2024 |
| AMT Machine Tools Ltd | Manufacturing | 2011 |
| Amyy Enterprises Ltd | Wholesale & retail | 2024 |
| Anchor Inn (Sutton Bonington) Ltd | Hospitality | 2009 |
| Andrawn Professional Services Ltd | Professional & scientific | 2020 |
| Andrei Mihai Company 01 Ltd | Administrative & support | 2017 |
| Andrew Klimowicz Limited | Administrative & support | 2010 |
| Andy Crewe Scaffolding Ltd | Construction | 2002 |
| Andy Elton Property Services Ltd | Real estate | 2015 |
| Angel Transport Ltd | Transport & logistics | 2020 |
| Anglo Aylesbury Management Ltd | Real estate | 2004 |
| Anita Super Cleaner Limited | Administrative & support | 2025 |
| ANJ CPC Solutions Ltd | Professional & scientific | 2023 |
| Annecy Property Ltd | Real estate | 2025 |
| Anson Building Ltd | Construction | 2018 |
| Antalis Limited | Professional & scientific | 1972 |
| Antalis Services Limited | Administrative & support | 2010 |
| Antenatal Training Ltd | Professional & scientific | 2023 |
| Anti Ramraid Solutions Ltd | Construction | 2021 |
| AP Cottages Limited | Households | 2020 |
| AP Sports Management Ltd | Arts & recreation | 2025 |
| AP22 Properties Limited | Real estate | 2024 |
| Apex Appoint Ltd | Administrative & support | 2020 |
| Apollo's Angels Enterprises Limited | Wholesale & retail | 2023 |
| Apply IT Consulting Ltd | Information & communication | 2019 |
| Appm Facilities Services Limited | Administrative & support | 2011 |
| Appm Lighting Contracts Ltd | Construction | 2019 |
| Aprime Ltd | Professional & scientific | 2021 |
| Aqua Ltd | Professional & scientific | 2010 |
| Arabis Couriers Limited | Administrative & support | 2008 |
| Arbor Print Management Limited | Manufacturing | 2003 |
| Archidexign Construction Ltd | Construction | 2026 |
| Ardh Limited | Professional & scientific | 2019 |
| Argyle Civil Engineering Ltd | Construction | 2026 |
| Arirai Property Limited | Real estate | 2022 |
| Aristica Stan Ltd | Transport & logistics | 2026 |
| Arjco Limited | Professional & scientific | 2020 |
| Arrida Financial Services Ltd | Financial services | 2026 |
| Artyarn Trading Limited | Wholesale & retail | 2010 |
| ASA Property Rentals Limited | Real estate | 2019 |
| Ascension Property & Holdings Limited | Financial services | 2025 |
| Ascension Scaffold Ltd | Construction | 2024 |
| ASH Tree Court Management Co. Ltd | Construction | 2006 |
| Ashby Moto Park Limited | Arts & recreation | 2016 |
| Ashfield Aesthetics Ltd | Other services | 2024 |
| Aspect Accountants Ltd | Professional & scientific | 2003 |
| Aspects Music Limited | Administrative & support | 2017 |
| Aspirant Coaching Limited | Professional & scientific | 2024 |
| Assistbda Ltd | Information & communication | 2026 |
| Associaction Enterprises Limited | Professional & scientific | 2003 |
| Associated International Cement Limited | Financial services | 1949 |
| Astalis Heating Ltd | Construction | 2024 |
| Astill Property Investments Ltd | Real estate | 2025 |
| ATB Landscapes Ltd | Administrative & support | 2022 |
| ATB Training Solutions Ltd | Education | 2025 |
| Atco Limited | Wholesale & retail | 2020 |
| Atjd Limited | Transport & logistics | 2025 |
| Atlas Plastering & DRY Lining (Holdings) Limited | Construction | 2011 |
| Atlas Plastering & DRY Lining Contractors Limited | Administrative & support | 2001 |
| Atmc UK Limited | Extraterritorial | 2012 |
| Atmosphere Landscapes Ltd | Administrative & support | 2025 |
| ATR Projects Ltd | Professional & scientific | 2025 |
| Auto Union Hire Ltd | Professional & scientific | 2012 |
| Autoquip of Leicester Limited | Wholesale & retail | 1993 |
| Autoscope Holdings Limited | Financial services | 2020 |
| Autoscope Limited | Wholesale & retail | 2012 |
| Autoworks U.K. Limited | Wholesale & retail | 2021 |
| Avanti Electrical Ltd | Construction | 2021 |
| Avat Hinckley Ltd | Hospitality | 2026 |
| Avery Richmond Ltd | Financial services | 2023 |
| AWB Estates Limited | Real estate | 2025 |
| AWK Ground Testing Limited | Administrative & support | 2017 |
| Axis Culture Group Ltd | Professional & scientific | 2025 |
| Axis Engineering Ltd | Professional & scientific | 2025 |
| Aydemir Brothers Property Limited | Real estate | 2025 |
| Ayliz & Co. Ltd | Manufacturing | 2025 |
| AYM Recruitment Ltd | Administrative & support | 2024 |
| Ayres Flooring Ltd | Wholesale & retail | 2023 |