| Alkap Resourcing Limited | Administrative & support | 2008 |
| Alkasis Ltd | Other services | 2019 |
| ALL About Names Limited | Wholesale & retail | 2002 |
| ALL About Newport Ltd | Information & communication | 2012 |
| ALL Bang & Strumit Limited | Extraterritorial | 2022 |
| ALL Glass Systems Limited | Manufacturing | 1984 |
| ALL Motor Leasing Limited | Financial services | 2017 |
| ALL Nations Inn Limited | Hospitality | 2004 |
| ALL Property Enterprise Ltd | Manufacturing | 2024 |
| ALL Weathers Lottery CIC | Financial services | 2021 |
| All-In-One Production Services Ltd | Administrative & support | 2024 |
| All-In-One Property Care Ltd | Administrative & support | 2025 |
| All-Tech Electronics Ltd | Manufacturing | 2023 |
| Allax Design Ltd | Professional & scientific | 2026 |
| Allen Consultancy Ltd | Professional & scientific | 2023 |
| Allen Farm Services Limited | Manufacturing | 2023 |
| Allen Nick Limited | Wholesale & retail | 2011 |
| Allerton 77 Limited | Real estate | 2022 |
| Allerton Road Investments Limited | Real estate | 2022 |
| Allesio Commerce Ltd | Wholesale & retail | 2025 |
| Allfleet Vehicle Solutions Limited | Administrative & support | 2014 |
| Alliance Estates Ltd | Real estate | 2016 |
| Allman JL Ltd | Wholesale & retail | 2023 |
| Allocate Resource Limited | Professional & scientific | 2023 |
| Alloy Ramps Limited | Manufacturing | 2021 |
| Allrounds Building Solutions Limited | Administrative & support | 2023 |
| Allscott Cars Ltd | Wholesale & retail | 2026 |
| Allscott Sports Club Cafe Limited | Hospitality | 2026 |
| Allscott Sports Club Ltd | Arts & recreation | 2022 |
| Allsports Coaches Coaching Academy CIC | Arts & recreation | 2020 |
| Allstar Flight Academy CIC | Education | 2026 |
| Alltech Consultancy Limited | Wholesale & retail | 2013 |
| ALM Engineering Ltd | Manufacturing | 2023 |
| Aloadofjunk.Com Ltd | Extraterritorial | 2018 |
| Alonson Ltd | Transport & logistics | 2026 |
| Aloyzas&Roberta Ltd | Transport & logistics | 2016 |
| Alpha Omega Safety Ltd | Construction | 2023 |
| Alpha Safety Specialist Ltd | Construction | 2025 |
| Alphanest Ltd | Information & communication | 2025 |
| Alphas Trades Ltd | Administrative & support | 2025 |
| Alpine Fireplace and Chimney Solutions Limited | Construction | 2023 |
| ALR Rentals Limited | Real estate | 2022 |
| Alrazak.Co.Uk Ltd | Hospitality | 2024 |
| Alrici Freight Limited | Transport & logistics | 2022 |
| ALS Fabs Limited | Manufacturing | 2009 |
| Alswines Limited | Wholesale & retail | 2012 |
| Altar of Worship Ministry Limited | Other services | 2025 |
| Alteo Expedition Ltd | Transport & logistics | 2019 |
| Altera Technologies Limited | Manufacturing | 2015 |
| Alternative Energy Solutions (Shropshire) Limited | Construction | 2011 |
| Altitude Aerial Photography Ltd | Information & communication | 2015 |
| Altitude Baits Ltd | Wholesale & retail | 2026 |
| Altitude Photography Ltd | Information & communication | 2017 |
| Altitude Photos Ltd | Information & communication | 2017 |
| Alto Electrical Limited | Construction | 2015 |
| Alubend Limited | Manufacturing | 2019 |
| Alubend UK Limited | Manufacturing | 2021 |
| Aluwall Ltd | Construction | 2023 |
| Alvaerium Ltd | Administrative & support | 2025 |
| Alvic Plastics Limited | Manufacturing | 2016 |
| Alx-Prox Limited | Transport & logistics | 2024 |
| Alyson Haywood Ltd | Professional & scientific | 2015 |
| AM & DA Group LLP | | 2017 |
| AM & Sons Property Maintenance Ltd | Other services | 2019 |
| AM Training Associates Ltd | Education | 2025 |
| AM08 Ltd | Wholesale & retail | 2026 |
| AMA Investment Properties Limited | Extraterritorial | 2019 |
| Amahera Ltd | Administrative & support | 2020 |
| Amalie Theatre Medic Limited | Health & social care | 2013 |
| Amanda JG Consultancy Limited | Information & communication | 2025 |
| Amanny Security Ltd | Administrative & support | 2026 |
| Amazing Alloys Shropshire Limited | Wholesale & retail | 2013 |
| Amazingict Limited | Information & communication | 2016 |
| Amber Loans Limited | Financial services | 2026 |
| Amclo Consultancy Limited | Information & communication | 2023 |
| Amcorp Estates Ltd | Construction | 2020 |
| Ameri Freight Limited | Transport & logistics | 2026 |
| American Nails in Wellington Limited | Other services | 2018 |
| Amery IT Support Ltd | Information & communication | 2022 |
| Amethyst (Telford) Limited | Real estate | 2011 |
| AMF SERVICES60 Ltd | Professional & scientific | 2026 |
| Amir White Galery Ltd | Wholesale & retail | 2025 |
| Amisela Ltd | Other services | 2020 |
| Ammp Ceylon Trading Limited | Wholesale & retail | 2026 |
| AMO Couriers Ltd | Transport & logistics | 2021 |
| Amore Moto Limited | Wholesale & retail | 2014 |
| Ampacet Distribution UK Limited | Manufacturing | 2013 |
| Ampacet UK Limited | Manufacturing | 2003 |
| Ample Power Limited | Construction | 2014 |
| Amplify Marketing U.K Ltd | Real estate | 2024 |
| Amrod (UK) Limited | Transport & logistics | 2012 |
| AMT Aircraft Engineering Ltd | Professional & scientific | 2026 |
| AMY Macs' Ltd | Wholesale & retail | 2025 |
| AN Electronics Company Ltd | Wholesale & retail | 2026 |
| AN Residential Ltd | Real estate | 2025 |
| Anagena Ltd | Other services | 2019 |
| Analytical Information Systems Limited | Information & communication | 1991 |
| Analytical Instrument Tube Systems Ltd | Manufacturing | 2012 |
| Anarew Ltd | Other services | 2019 |
| Anastom Ltd | Professional & scientific | 2026 |