| Akkadium College of Education Research and Development Limited | Professional & scientific | 2017 |
| Akkadium Consulting Limited | Professional & scientific | 2018 |
| Akkadium Limited | Professional & scientific | 2017 |
| AKP Training Ltd | Arts & recreation | 2020 |
| AKS Brickwork Ltd | Construction | 2014 |
| Alarm ME Fast Ltd | Administrative & support | 2013 |
| ALB Transport & Logistics Ltd | Transport & logistics | 2024 |
| Alberto Engineering Ltd | Professional & scientific | 2024 |
| Alchemy Business Services Limited | Construction | 1998 |
| Alecia Antonette Property Investment Ltd | Real estate | 2023 |
| Alex Leonard Edit Ltd | Information & communication | 2017 |
| Alex Repair Ltd | Construction | 2018 |
| Alexander Stephens Ltd | Extraterritorial | 2008 |
| Alexandra Wilson Curtains & Blinds Ltd | Manufacturing | 2022 |
| Alexandra Wilson Interior Design Ltd | Professional & scientific | 2016 |
| Alhen Pro-Services Ltd | Construction | 2025 |
| Alkemist Media Limited | Arts & recreation | 2002 |
| Allen Event Catering Ltd | Hospitality | 2023 |
| Alliance Heat Ltd | Construction | 2017 |
| Allround Tech Services Limited | Arts & recreation | 2012 |
| Alonat Group International Ltd | Transport & logistics | 2026 |
| Alpha Numeric Multi-Media Ltd | Information & communication | 2008 |
| Alpine Interiors Ltd | Construction | 2023 |
| Alsa Consultancy Services Limited | Professional & scientific | 2019 |
| Alvex Ltd | Manufacturing | 2025 |
| Amba Installations Limited | Construction | 2015 |
| Amber ARC Studio Ltd | Manufacturing | 2024 |
| Amber Engineering Services Ltd | Wholesale & retail | 2017 |
| Amialo Limited | Wholesale & retail | 2021 |
| Amoc Foods Ltd | Hospitality | 2025 |
| Amore Auctions and Clearance Limited | Wholesale & retail | 2023 |
| Amya Limited | Professional & scientific | 2006 |
| Andrew Rawlings Building Ltd | Construction | 2022 |
| Andrews Primespace Ltd | Real estate | 2026 |
| Andy Cooling Haulage Limited | Transport & logistics | 2020 |
| Andy Foster Commercial Services Ltd | Professional & scientific | 2019 |
| Angel Wings Properties Ltd | Real estate | 2026 |
| Angels-Touch Care Ltd | Public administration | 2022 |
| ANN Mcgregor Limited | Wholesale & retail | 2025 |
| AP2 Maintenance Services Ltd | Manufacturing | 2024 |
| Apbl Limited | Wholesale & retail | 2026 |
| APC Therapies Ltd | Other services | 2023 |
| Apex Appointments Ltd | Information & communication | 2018 |
| Apex Comms Limited | Administrative & support | 2019 |
| Apex Premium Car Care Ltd | Administrative & support | 2024 |
| Apex Pubs Ltd | Hospitality | 2026 |
| Aphex Properties & Co Ltd | Real estate | 2023 |
| Aphex Properties ( Projects ) Ltd | Construction | 2024 |
| APM Electrical and Mechanical Ltd | Construction | 2026 |
| Aqua Pro Maintenance Ltd | Construction | 2026 |
| Aralex Property Limited | Real estate | 2019 |
| Aralex Property Sourcing Ltd | Real estate | 2023 |
| ARB Controls Ltd | Professional & scientific | 2014 |
| Arburies Ltd | Construction | 2000 |
| Architecture Workshop Ltd | Professional & scientific | 2021 |
| Arcsilea Ltd | Professional & scientific | 2018 |
| Arcsilea Partners LLP | | 2023 |
| Ardit Building Ltd | Construction | 2022 |
| Argus Black Swan International Limited | Administrative & support | 2022 |
| Argus Black Swan Limited | Mining & quarrying | 2013 |
| Arianna and Oana Ltd | Transport & logistics | 2019 |
| Aristo Universal Limited | | 1982 |
| Arloweservices Limited | Construction | 2017 |
| Art Catering Ltd | Hospitality | 2019 |
| Art Equipment Ltd | Manufacturing | 2007 |
| Art Software Ltd | Information & communication | 2007 |
| Artax Accountancy Services Ltd | Professional & scientific | 2017 |
| Artcon Electronics Ltd | Manufacturing | 2023 |
| Artificial Lawns & Landscaping (Northants) Ltd | Administrative & support | 2024 |
| ARV Chimney Sweeps Ltd | Administrative & support | 2013 |
| AS James Holdings Ltd | Hospitality | 2022 |
| Asancha Limited | Real estate | 2024 |
| Asfi Limited | Real estate | 2025 |
| Ashishveda PVT Ltd | Health & social care | 2023 |
| Ashlyn's Cafe Limited | Hospitality | 2025 |
| Asia-Tek Ltd | Manufacturing | 2009 |
| Aspendos Ltd | Hospitality | 2018 |
| Astonmart World Limited | Other services | 2025 |
| Atm-First Project Consultants Ltd. | Construction | 2017 |
| Atom Cutting Systems (UK) Ltd | Extraterritorial | 2021 |
| ATP Foods Ltd | Hospitality | 2020 |
| Attgills Limited | Water & waste | 2019 |
| Aura&Bilt Limited | Transport & logistics | 2025 |
| Auto Telecom Solutions Ltd | Information & communication | 2013 |
| Autocentre (Rushden) Limited | Wholesale & retail | 2005 |
| Avardi Limited | Construction | 2020 |
| Awake Organics Ltd | Manufacturing | 2017 |
| Axisbyte Group Limited | Wholesale & retail | 2025 |
| Ayden Kayla Properties Ltd | Real estate | 2024 |
| Azizi Properties Limited | Real estate | 2018 |
| Aztec (U.K.) Limited | Wholesale & retail | 1987 |
| Azul Events Ltd | Administrative & support | 2025 |
| B B Canopies Ltd | Construction | 2016 |
| B&R Electrical Team Ltd | Construction | 2019 |
| B.P.H Driver Services Ltd | Administrative & support | 2013 |
| B1D Auctions Ltd | Wholesale & retail | 2023 |
| B2B Graphics Ltd | Manufacturing | 2025 |
| Babas Diner Ltd | Hospitality | 2025 |
| Bade Catering Limited | Hospitality | 2014 |
| Bagmagic Ltd | Wholesale & retail | 2026 |