| AARVIENTERPRISE5912 Ltd | Information & communication | 2021 |
| Aatb Limited | Administrative & support | 2025 |
| Aats (Accounting and Tax Solutions) Ltd | Real estate | 2024 |
| Aayan & Co Luton Limited | Wholesale & retail | 2025 |
| AB Acres Ltd | Real estate | 2023 |
| AB Adventure Builders Ltd | Construction | 2024 |
| AB Cars Limited | Wholesale & retail | 2019 |
| AB Cricket Ltd | Wholesale & retail | 2026 |
| AB Driving Ltd | Education | 2024 |
| AB Furniture and Appliances Ltd | Wholesale & retail | 2022 |
| AB Health Consultancy Ltd | Health & social care | 2023 |
| AB Mini Market Limited | Wholesale & retail | 2026 |
| AB Property Group Ltd | Real estate | 2019 |
| AB Software Solutions Ltd | Information & communication | 2019 |
| AB3PROPERTY Ltd | Real estate | 2025 |
| AB3RECRUITMENT Ltd | Other services | 2023 |
| AB3SECURITY Ltd | Administrative & support | 2024 |
| ABA Atelier Ltd | Wholesale & retail | 2026 |
| Abaa Consulting Limited | Other services | 2012 |
| Ababil Travel and Tours Ltd | Transport & logistics | 2016 |
| Abacus Electrical Services Ltd | Construction | 2025 |
| Abacus Financial Services Limited | Professional & scientific | 1987 |
| Abam Foods Limited | Wholesale & retail | 2020 |
| Abatee Ltd | Wholesale & retail | 2017 |
| Abbas Foundation | Other services | 2023 |
| Abbasy Consulting Ltd | Professional & scientific | 2019 |
| Abbey Land Developments Limited | Construction | 2014 |
| Abbey Mage I.T. Services Ltd | | 2013 |
| Abbeygate Business Centre Management Limited | Administrative & support | 1982 |
| Abbot Duplicate Book Company Limited | Real estate | 1924 |
| Abbot Print Ltd | Manufacturing | 1980 |
| Abbott Solicitors LLP | | 2015 |
| Abbotts Properties Limited | Real estate | 2024 |
| Abbran Homes Limited | Real estate | 2021 |
| ABC Bar Ltd | Hospitality | 2025 |
| ABC Construction Projects Ltd | Wholesale & retail | 2003 |
| ABC Family Law Services Limited | Professional & scientific | 2017 |
| ABD Superstore Ltd | Wholesale & retail | 2024 |
| Abdex Hose & Couplings Limited | Manufacturing | 1982 |
| Abdul Go Limited | Transport & logistics | 2025 |
| Abdul Hafiz Properties Ltd | Real estate | 2024 |
| Abdul Halal Meat Marsh Farm Limited | Wholesale & retail | 2024 |
| Abdulenterprise Ltd | Wholesale & retail | 2025 |
| Abdullah Transport Limited | Transport & logistics | 2019 |
| Abdulsalam Traderz Ltd | Wholesale & retail | 2026 |
| Abdur Rahmaan & Co Limited | Transport & logistics | 2017 |
| ABE Zamzam Ltd | Hospitality | 2021 |
| Abedin & Associates Limited | Health & social care | 2017 |
| Abefe Global Limited | Wholesale & retail | 2024 |
| Abegye Ltd | Health & social care | 2019 |
| Abel Property Investments Ltd | Real estate | 2021 |
| Abella Properties Limited | Real estate | 1981 |
| Abena's Authentic Kitchen Ltd | Hospitality | 2023 |
| ABF Accounting Services Ltd | Professional & scientific | 2023 |
| ABF Smart Solutions Limited | Wholesale & retail | 2024 |
| Abhaysingh Manoharsingh Ltd | Construction | 2024 |
| Abhz Supplies Ltd | Wholesale & retail | 2025 |
| Abibi Investments Ltd | Real estate | 2017 |
| ABID94 Ltd | Health & social care | 2024 |
| Abidem Limited | Health & social care | 2020 |
| Abidev Ltd | Real estate | 2023 |
| Ability Housing Group Ltd | Real estate | 2025 |
| Abimaher Limited | Health & social care | 2021 |
| Abis Engineering Ltd | Professional & scientific | 2026 |
| Abjsm Ltd | Real estate | 2020 |
| ABK Automotive Ltd | Wholesale & retail | 2017 |
| ABK Trading Ltd | Wholesale & retail | 2023 |
| Abobvo Links Ltd | Public administration | 2021 |
| Abode Luton Ltd | Real estate | 2023 |
| Aboh Residentials Ltd | Real estate | 2020 |
| Aboo London Ltd | Real estate | 2015 |
| Abou Baker Security Ltd | Administrative & support | 2021 |
| About Burgers Ltd | Hospitality | 2024 |
| ABP Pharma Limited | Wholesale & retail | 2022 |
| Abraar Automotive Ltd | Wholesale & retail | 2019 |
| Abraham Euro Logistics Limited | Wholesale & retail | 2024 |
| Abrahams (Property & Civil Engineering Consultants) Limited | Administrative & support | 2015 |
| Abram Creative Ltd | Information & communication | 2025 |
| Abrudan Build Ltd | Construction | 2025 |
| ABS Collectors Ltd | Administrative & support | 2025 |
| ABS Tech Ltd | Information & communication | 2024 |
| ABS UK Luton Limited | Transport & logistics | 2025 |
| Absa Investments Limited | Real estate | 2015 |
| Absolute Paving Ltd | Administrative & support | 2024 |
| Absolute Plumbing & GAS Solutions Ltd | Construction | 2014 |
| Absolute Roofing Services Ltd | Construction | 2025 |
| Abstract Addict Ltd | Wholesale & retail | 2025 |
| ABU Construction Ltd | Construction | 2018 |
| Abu's Kitchen Ltd | Wholesale & retail | 2025 |
| Abubakar Traders Ltd | Wholesale & retail | 2025 |
| Abundance Alchemy Online Ltd | Information & communication | 2025 |
| ABZ Goodz and Fragrancez Ltd | Wholesale & retail | 2025 |
| Abzoya Ltd | Real estate | 2026 |
| Abztalks Ltd | Information & communication | 2021 |
| AC Herts Caravan Sites Limited | Real estate | 2023 |
| AC Legal Marketing Ltd | Professional & scientific | 2017 |
| AC Property Investment Ltd | Real estate | 2024 |
| AC10 Ltd | Wholesale & retail | 2020 |
| AC7 Group Ltd | Construction | 2023 |
| ACA Shah Marketing Ltd | Professional & scientific | 2026 |