| Alltrade BP Ltd | Wholesale & retail | 2025 |
| Allts & Co Limited | Professional & scientific | 2020 |
| Alltub UK Limited | Wholesale & retail | 2005 |
| Allways Concreting Ltd | Construction | 2021 |
| Allways Recruitment Ltd | Administrative & support | 2023 |
| Allworks Home Improvements Ltd | Construction | 2005 |
| Allystone Ltd | Other services | 2017 |
| Alma House Associates Ltd | Professional & scientific | 2013 |
| Almadeenahservices Ltd | Wholesale & retail | 2025 |
| Almes DRY Lining Ltd | Construction | 2025 |
| Almouslli Dental Ltd | Health & social care | 2019 |
| Almunir Specialist Catering Ltd | Hospitality | 2021 |
| Alnz Holding Co Ltd | Financial services | 2023 |
| Aloevera Cares Ltd | Administrative & support | 2018 |
| Alongwithyou Ltd | Administrative & support | 2026 |
| Alox HR Group Ltd | Transport & logistics | 2026 |
| ALP Developments (Cambs) Limited | Construction | 2008 |
| ALP Property Investments & Management Ltd | Real estate | 2017 |
| ALP Windows, Doors and Conservatories Ltd | Construction | 2017 |
| ALPH4 Cleaning Ltd | Administrative & support | 2024 |
| Alpha Accident Group Limited | Transport & logistics | 2025 |
| Alpha Barbering Limited | Other services | 2021 |
| Alpha Communications Limited | Administrative & support | 2007 |
| Alpha Law Chambers Ltd | Professional & scientific | 2019 |
| Alpha Milton Rentals Ltd | Real estate | 2025 |
| Alpha Motor Sales Limited | Wholesale & retail | 2025 |
| Alpha Park Management Company Limited | Real estate | 1987 |
| Alpha Powder Coatings (WET Paint) Limited | Manufacturing | 2009 |
| Alpha Stone Ltd | Construction | 2019 |
| Alpha Strike Games Limited | Information & communication | 2017 |
| Alpha Telecom Limited | Information & communication | 2019 |
| Alpha Training Personnel Ltd | Education | 2024 |
| Alpha Truck Limited | Transport & logistics | 2022 |
| Alphadatapapa Ltd | Information & communication | 2019 |
| Alphaguard Ltd | Administrative & support | 2023 |
| Alphamax Capital Limited | Administrative & support | 2008 |
| Alpine Auto Group Limited | Wholesale & retail | 2022 |
| Alpine Private Wealth Ltd | Financial services | 2024 |
| Alpine Tree Care & Landscaping Ltd | Construction | 2026 |
| Alps Investments Ltd | Real estate | 2025 |
| Alrend Design Services Ltd | Construction | 2022 |
| Alrose Products Limited | Manufacturing | 1985 |
| Alsam Catering Ltd | Hospitality | 2019 |
| Alshan Transport Ltd | Transport & logistics | 2022 |
| Alspedcargo Ltd | Transport & logistics | 2023 |
| Alston Country Homes Limited | Construction | 1983 |
| Alston Court (Langtoft) Management Limited | Households | 2004 |
| Alston Holdings (Lincs) Ltd | Administrative & support | 2024 |
| Alta Law Ltd | Professional & scientific | 2023 |
| Alter-Ego Athletic Limitless Projects CIC | Arts & recreation | 2025 |
| Alterdd Ltd | Information & communication | 2025 |
| Alternative Curriculum Education Centre C.I.C. | Education | 2006 |
| Altevus Ltd. | Professional & scientific | 2024 |
| Altin Makasi Ltd | Other services | 2025 |
| Altivium Ltd | Wholesale & retail | 2025 |
| Alto Environmental Ltd | Extraterritorial | 2013 |
| Altprocure Ltd | Professional & scientific | 2025 |
| Altrucare Limited | Information & communication | 2015 |
| Altta Group Limited | Education | 2013 |
| Altta Limited | Education | 2014 |
| Altynski Ltd | Transport & logistics | 2017 |
| Aluminium and Glass Facades Limited | Manufacturing | 1992 |
| Aluxeprints Ltd | Manufacturing | 2022 |
| Alva Generator and Excitation Services Ltd | Manufacturing | 2011 |
| Alvas Telecoms Ltd | Information & communication | 2021 |
| Alverton and Croyland Limited | Professional & scientific | 2020 |
| Alves Icare Ltd | Health & social care | 2018 |
| Alwalton Cars Ltd | Transport & logistics | 2026 |
| Alwalton Hall Limited | Professional & scientific | 2015 |
| Alwalton Management Company Limited | Real estate | 2021 |
| Always Jetlagged Limited | Administrative & support | 2025 |
| ALX Drivers Limited | Transport & logistics | 2018 |
| Alycare Ltd | Health & social care | 2020 |
| Alyn SI Carmen Ltd | Construction | 2024 |
| Alyn Transport Ltd | Transport & logistics | 2024 |
| AM Blinds Ltd | Manufacturing | 2025 |
| AM Fresh UK Limited | Wholesale & retail | 2002 |
| AM Land Ltd | Construction | 2023 |
| AMA City Investments Ltd | Real estate | 2025 |
| AMA Edition Limited | Transport & logistics | 2022 |
| AMA FRU Enterprises Limited | Professional & scientific | 2016 |
| AMA Motors Group Limited | Wholesale & retail | 2020 |
| Amaana Hair and Beauty Ltd | Other services | 2025 |
| Amace Ltd | Wholesale & retail | 2026 |
| Amachi Concept Limited | Administrative & support | 2025 |
| Amae Transport Ltd | Transport & logistics | 2026 |
| Amai Nest Ltd | Real estate | 2025 |
| Amaks Medical Services & Suppliers Ltd | Health & social care | 2018 |
| Amalia Transportation Ltd | Transport & logistics | 2023 |
| Amanda Collins Consulting Limited | Other services | 2021 |
| Amanda Court Management (Peterborough) Limited | Households | 1971 |
| Amanda Mealing Limited | Arts & recreation | 2004 |
| Amarax Limited | Information & communication | 2018 |
| Amase Group Holdings Limited | Real estate | 2025 |
| Amateur Darts Circuit E F Limited | Education | 2023 |
| AMAZE1 Ltd | Wholesale & retail | 2025 |
| Amazeu Solutions Limited | Administrative & support | 2017 |
| AMB Desserts Ltd | Hospitality | 2024 |
| AMB Financial Ltd | Financial services | 2017 |
| AMB Real Investment Ltd | Real estate | 2017 |