| ALL 4 Corners Ltd | Construction | 2025 |
| ALL for Theodore Ltd | Wholesale & retail | 2024 |
| Allegro Gymnastic Academy Limited | Arts & recreation | 2016 |
| Alpha 2 Bravo Aircraft Delivery Ltd | Other services | 2022 |
| Alpha 3 Manufacturing Limited | Manufacturing | 1972 |
| Alpha Marketing Solutions Limited | Administrative & support | 2016 |
| Alphabite Ltd | Information & communication | 2022 |
| Altiorvita Trading Ltd | Wholesale & retail | 2010 |
| Altomode Limited | Real estate | 1986 |
| Aly&Faby Trans Ltd | Transport & logistics | 2026 |
| AM & Tech Ltd | Construction | 2020 |
| AM Interim Limited | Professional & scientific | 2015 |
| AMA Properties (Lincolnshire) Limited | Real estate | 2022 |
| Ambara Ltd | Wholesale & retail | 2026 |
| Ambassador Training and Consultancy Limited | Education | 2013 |
| Amber Adult Social Care Limited | Health & social care | 2007 |
| AMC Portfolio Ltd | Real estate | 2017 |
| Amelio Ltd | Information & communication | 2009 |
| American Diner 6 Ltd | Hospitality | 2025 |
| AMERICANDINERROUTE16 Limited | Hospitality | 2025 |
| AMG Capital Ltd | Real estate | 2024 |
| Ammg Care Limited | Hospitality | 2011 |
| Amor Cleaning Ltd | Administrative & support | 2025 |
| Amped Ltd | Wholesale & retail | 2022 |
| Amphion Home Care Services Limited | Health & social care | 1997 |
| Amphion Lodge Limited | Health & social care | 2004 |
| Amphion View Limited | Health & social care | 2007 |
| Amps Express Logistics Ltd | Transport & logistics | 2025 |
| Amps Surgical Limited | Health & social care | 2017 |
| Amrz Ltd | Health & social care | 2024 |
| AMS Bobcat Limited | Wholesale & retail | 1999 |
| AMS IT Systems Limited | Information & communication | 2026 |
| AMS No-Dig Limited | Construction | 1992 |
| AMS Pathology Limited | Health & social care | 2022 |
| Amscrub Limited | Health & social care | 2023 |
| AMT2 Limited | Financial services | 2015 |
| Amvale Holdings Limited | Financial services | 2015 |
| Amvale Limited | Administrative & support | 1985 |
| Amvale Medical Transport Limited | Administrative & support | 2002 |
| Amvale Trustees Limited | Administrative & support | 2025 |
| AMW Ceng Ltd | Professional & scientific | 2022 |
| AMY Transport Solution Ltd | Transport & logistics | 2025 |
| AN Dermatology Consulting Ltd | Health & social care | 2024 |
| Ana-Sofia Ltd | Transport & logistics | 2024 |
| Anaabia’S Ltd | Hospitality | 2026 |
| Anastasia Valeria Ltd | Transport & logistics | 2023 |
| ANC Roofing Ltd | Construction | 2015 |
| Anchorpoint Safety Systems Limited | Construction | 2007 |
| Ancora Healthcare Limited | Wholesale & retail | 2011 |
| Anderson Catering Scunthorpe Ltd | Hospitality | 2023 |
| ANDKOZU43 Ltd | Wholesale & retail | 2024 |
| Andreea-Roxana Ltd | Transport & logistics | 2023 |
| Andrei Transport Services Limited | Transport & logistics | 2023 |
| Andrew Fletcher Photo Journalist Limited | Arts & recreation | 2010 |
| Andrew Levison Ltd | Health & social care | 2010 |
| Andrew Page Consulting Limited | Administrative & support | 2016 |
| Andrew Thomas Accountancy Limited | Professional & scientific | 2007 |
| Andy Bancroft Contracting and Consultancy Limited | Construction | 2017 |
| Andy Thompson Limited | Real estate | 2014 |
| ANG Urbantrans Ltd | Transport & logistics | 2024 |
| Angel Paws Ltd | Other services | 2020 |
| Anglo Plastics Limited | Wholesale & retail | 1994 |
| Anidd Ltd | Transport & logistics | 2018 |
| Animal Heaven Ltd | Other services | 2026 |
| ANIMALROB88TCG Ltd | Wholesale & retail | 2024 |
| Anjali Advisory Ltd | Professional & scientific | 2024 |
| Anna Health and Beauty Treatments Ltd | Health & social care | 2022 |
| Anna's Nails Limited | Other services | 2017 |
| Annmar Limited | Transport & logistics | 2024 |
| ANP Unicorn Limited | Health & social care | 2020 |
| Ansz Builds Ltd | Construction | 2024 |
| Antarix Medical Ltd | Professional & scientific | 2026 |
| Anthony's Korean Kitchen Ltd | Hospitality | 2025 |
| Antohe Properties Ltd | Real estate | 2025 |
| Antonio Haulage Ltd | Transport & logistics | 2025 |
| Antonio Marius Couriers Ltd | Transport & logistics | 2025 |
| Antony's Catering and Bakes Ltd | Wholesale & retail | 2026 |
| Antyx Animation (Phobes) Limited | Information & communication | 2009 |
| Antyx Ltd | Information & communication | 2011 |
| Anubis Delivery Ltd | Wholesale & retail | 2026 |
| AOG Services Ltd | Professional & scientific | 2023 |
| AP Property Management U.K. Services Ltd | Real estate | 2020 |
| Apassessments Limited | Professional & scientific | 2010 |
| APB Landscaping Limited | Construction | 2023 |
| APC Leisure Ltd | Arts & recreation | 2026 |
| APC Recruitment Limited | Administrative & support | 2026 |
| Apex DR Ltd | Health & social care | 2024 |
| Apex Initiatives (Apexi) Limited | Administrative & support | 2023 |
| Apex Keys & Tuning Ltd | Wholesale & retail | 2025 |
| Apexi Digital Limited | Information & communication | 2026 |
| Aphrodite Aesthetics & Skincare Limited | Other services | 2022 |
| Apicius Catering Ltd | Hospitality | 2020 |
| Apna Local (Beechway) Limited | Wholesale & retail | 2012 |
| Apnwis Ltd | Transport & logistics | 2019 |
| Apollo Air Conditioning Ltd | Energy | 2013 |
| Apollo Industrial Supplies Limited | Administrative & support | 2017 |
| Apollo Recruitment Limited | Administrative & support | 1998 |
| Apollo Site Services Limited | Administrative & support | 1996 |
| App Frod Sports Club CIC | Arts & recreation | 2025 |
| Appleby Frodingham Football Club Sports Bar Ltd | Other services | 2026 |