| AA Marketing Limited | Administrative & support | 2013 |
| Aaeon Systtem Ltd | Professional & scientific | 2021 |
| Aamax Consultants Limited | Professional & scientific | 2016 |
| AAO Alliance Venture Ltd | Real estate | 2024 |
| Aarmadillo Limited | Professional & scientific | 2015 |
| Aaro Consultancy Services Limited | Information & communication | 2015 |
| Aaron Camera Ltd | Information & communication | 2021 |
| Aashi Property Ltd | Real estate | 2024 |
| Aayu Corporation Ltd | Wholesale & retail | 2018 |
| Aayush Engineers Ltd | Construction | 2016 |
| AB & P Ltd | Wholesale & retail | 2026 |
| AB Consultancy for YOU Ltd | Information & communication | 2025 |
| AB Consultants Ltd | Professional & scientific | 2026 |
| AB Interiors London Ltd | Professional & scientific | 2025 |
| AB Load Haulage Ltd | Administrative & support | 2026 |
| ABA Professional Services Network Ltd | Professional & scientific | 2021 |
| Abacus Edge Stellar LLP | | 2024 |
| Abbeysafe Limited | Administrative & support | 2007 |
| Abbots Estates Ltd | Households | 2005 |
| Abbott T & C Limited | Transport & logistics | 2021 |
| Abc's Estates Ltd | Real estate | 2021 |
| Abelsimo Ltd | Manufacturing | 2019 |
| Abideen Ltd | Wholesale & retail | 2024 |
| Ability Security Consultants Ltd | Administrative & support | 2011 |
| Abitha Consulting Limited | Information & communication | 2018 |
| Able Construction Solutions Limited | Construction | 2023 |
| Abode Heating Ltd | Energy | 2020 |
| Abra Marketing Management Limited | Professional & scientific | 2026 |
| ABS Partnership Limited | Real estate | 2001 |
| ABS Transport Service Ltd | Transport & logistics | 2024 |
| Abyat Ltd | Real estate | 2023 |
| AC UK Consultants Limited | Information & communication | 2016 |
| Aca-Toro Ltd | Financial services | 2022 |
| Academic Aliance Ltd | Professional & scientific | 2025 |
| Academic Allianz Ltd | Professional & scientific | 2025 |
| Acadmed 1985 Ltd | Other services | 2019 |
| Acana Care Ltd | Wholesale & retail | 2020 |
| Accd Ltd | Transport & logistics | 2025 |
| Accession Plus Limited | Professional & scientific | 2019 |
| Accountancy of West London Ltd | Professional & scientific | 2021 |
| Accrue Holdings Limited | Real estate | 2015 |
| Ace Apartments and Properties Ltd | Construction | 2019 |
| Ace Investments Limited | Hospitality | 2006 |
| Ace PHG Ltd | Construction | 2021 |
| Acer Care Limited | Wholesale & retail | 2020 |
| ACG Flooring Ltd | Construction | 2017 |
| ACH Wood Ltd | Construction | 2024 |
| ACL Autos Ltd | Transport & logistics | 2025 |
| Acmi International Ltd | Transport & logistics | 2023 |
| Acorn 1 Ltd | Professional & scientific | 2011 |
| Acorn Gardens Ltd | Households | 2022 |
| Acorn Paving Contractors Ltd | Administrative & support | 2025 |
| Acorn Roofing Contractors Ltd | Construction | 2025 |
| ACR Motors Limited | Wholesale & retail | 2011 |
| Action for Reducing Carbon Limited | Professional & scientific | 2007 |
| Active Early Years Academy Limited | Education | 2016 |
| Active Penguin Limited | Administrative & support | 2017 |
| Active Roofing and General Builders Limited | Construction | 2012 |
| Active Swim Academy Ltd | Education | 2025 |
| Active Swim Dolphin Limited | Arts & recreation | 2017 |
| Active Swim Limited | Arts & recreation | 2016 |
| Active Swim Seahorse Ltd | Arts & recreation | 2019 |
| Acu-Herbs Health Care Limited | Health & social care | 2005 |
| Acucoaching Services Ltd | Administrative & support | 2016 |
| Acuconsult Limited | Professional & scientific | 1993 |
| AD Ducendum Limited | Professional & scientific | 2014 |
| Adams Schoolwear Limited | Manufacturing | 2017 |
| Adaptive Globalization Ltd | Administrative & support | 2020 |
| Addurn Ltd | Manufacturing | 2020 |
| Adedoyin Ltd | Health & social care | 2025 |
| Adekho Ltd | Wholesale & retail | 2021 |
| Adica Ltd | Construction | 2013 |
| Adiporium Ltd | Information & communication | 2019 |
| Adishka SPV Ltd | Real estate | 2021 |
| Aditud Ltd | Transport & logistics | 2021 |
| Aditya Prusty Limited | Information & communication | 2024 |
| ADL Crash Repairs Limited | Wholesale & retail | 2007 |
| ADL Investments Limited | Real estate | 2007 |
| Admiral Property Care Limited | Construction | 2023 |
| ADO90 Limited | Professional & scientific | 2023 |
| Adonis London Cosmetics Ltd | Health & social care | 2018 |
| Adorn LUX Jewel Ltd | Wholesale & retail | 2023 |
| ADP Design & Build Ltd | Construction | 2021 |
| ADP Windows Ltd | Construction | 2019 |
| Advance Car Specialists Ltd | Wholesale & retail | 2017 |
| Advance R Holdings Ltd | Real estate | 2024 |
| Advance Trading Partners Limited | Wholesale & retail | 2024 |
| Advanced Construction Iver Ltd | Construction | 2012 |
| Advanced Landscaping Services Limited | Agriculture & fishing | 2006 |
| Advanced Roofers Limited | Construction | 2023 |
| Advanced Tree Surgeons Limited | Agriculture & fishing | 2021 |
| Advanced Waste Management Limited | Water & waste | 2020 |
| ADW Financial Solutions Limited | Financial services | 2017 |
| AE Business Analysts Limited | Administrative & support | 2024 |
| AEA Construction Ltd | Construction | 2022 |
| AEA Transport Ltd | Transport & logistics | 2020 |
| Aegle Leaves Limited | Information & communication | 2021 |
| Aeson Limited | Wholesale & retail | 2026 |
| Aetherlite Ltd | Professional & scientific | 2025 |
| Aevus & Co Limited | Transport & logistics | 2014 |