| Absolute Merc-Commercial Ltd | Wholesale & retail | 2020 |
| Absolutio Ltd | Financial services | 2018 |
| Absurd Curds Limited | Hospitality | 2025 |
| ABU Consultancy Limited | Professional & scientific | 2023 |
| Abubakarwaqas Ltd | Information & communication | 2025 |
| Abundant World Ltd | Information & communication | 2020 |
| AC Business Consultant Ltd | Financial services | 2012 |
| AC Commerce BR Limited | Wholesale & retail | 2025 |
| AC Gametech Ltd | Wholesale & retail | 2025 |
| AC Health Ltd | Health & social care | 2026 |
| AC Human Capital Consulting Ltd | Professional & scientific | 2019 |
| ACA World Ltd | Wholesale & retail | 2022 |
| Acacia Buildings Ltd | Construction | 2010 |
| Acacia Knowledge Limited | Professional & scientific | 2016 |
| Acacia Premium Healthcare Ltd | Health & social care | 2024 |
| Acca Hub Ltd | Wholesale & retail | 2025 |
| Accessible Property Lets Ltd | Hospitality | 2019 |
| Accidental Alchemy Ltd | Wholesale & retail | 2024 |
| Accolade Windows Limited | Construction | 2015 |
| Acconomy Limited | Professional & scientific | 2009 |
| Acconomy VFD Limited | Professional & scientific | 2014 |
| Account Release Partners Ltd | Information & communication | 2026 |
| Accountancy Plus Group Ltd | Professional & scientific | 2019 |
| Accountants & Business Solutions Limited | Information & communication | 2001 |
| Accounting and Payroll Services Limited | Professional & scientific | 2001 |
| Accounts Made Easy Limited | Professional & scientific | 2022 |
| Accquis Group Limited | Administrative & support | 2019 |
| Accrue Accounting Limited | Extraterritorial | 2023 |
| Accrue Sales and Marketing Limited | Professional & scientific | 2023 |
| Accujet Limited | Manufacturing | 2009 |
| Accupapers Limited | Information & communication | 2026 |
| Accuretta Systems Limited | Wholesale & retail | 2021 |
| Acdx Limited | Wholesale & retail | 2021 |
| Ace Clan Nexus Ltd | Wholesale & retail | 2025 |
| Ace Freehold Limited | Real estate | 2023 |
| Ace Glass & Mirrors Limited | Manufacturing | 2007 |
| Ace High Sports Ltd | Information & communication | 2023 |
| Ace Machinery Limited | Manufacturing | 2024 |
| Ace Property Restoration Limited | Construction | 1986 |
| Ace Reclamation Ltd | Wholesale & retail | 2004 |
| Ace Safes (UK) Ltd | Administrative & support | 2015 |
| Aceably Limited | Transport & logistics | 2017 |
| Aceusmle Ltd | Wholesale & retail | 2024 |
| Acfa Ltd | Households | 2016 |
| Achiever's Infotech Ltd | Wholesale & retail | 2024 |
| Achille Construction Service Ltd | Administrative & support | 2025 |
| Achw Limited | Administrative & support | 2025 |
| ACM Facilities Management Services Ltd | Administrative & support | 2012 |
| ACM Property Ltd | Real estate | 2022 |
| ACO Building Company UK Limited | Administrative & support | 2019 |
| Acps Projects Limited | Construction | 2025 |
| Acqua Dell'Elba UK Ltd | Wholesale & retail | 2024 |
| Acqua Homes Ltd | Real estate | 2023 |
| Acquit Debt Recovery Limited | Administrative & support | 2010 |
| Acre & Artisan Ltd | Wholesale & retail | 2026 |
| Acre Network Limited | Information & communication | 2025 |
| Acre Solutions Limited | Professional & scientific | 2018 |
| Across 110TH Ltd. | Professional & scientific | 2015 |
| ACS Absolute Cleaning Supplies Limited | Wholesale & retail | 2007 |
| ACS Event Services Limited | Extraterritorial | 2013 |
| ACS Group of Companies Limited | Extraterritorial | 2015 |
| ACS Testing Limited | Professional & scientific | 2003 |
| ACT Safe Global Ltd | Professional & scientific | 2026 |
| Actalink Limited | Information & communication | 2025 |
| Actiholdings Limited | Households | 2015 |
| Action Clearance Ltd | Water & waste | 2025 |
| Action Points Consulting Ltd | Information & communication | 2020 |
| Actisense Limited | Extraterritorial | 2010 |
| Active Energy Information Systems Ltd | Professional & scientific | 2020 |
| Active Gymnastics Club Limited | Arts & recreation | 2025 |
| Active Health Limited | Health & social care | 2006 |
| Active HIP and Knee Limited | Health & social care | 2014 |
| Active Research Limited | Manufacturing | 1996 |
| Active Solutions WW Ltd | Professional & scientific | 2023 |
| Activeweartrade Limited | Wholesale & retail | 2023 |
| Actuality 360 Limited | Extraterritorial | 2024 |
| ACU Handyman Ltd | Construction | 2019 |
| Acuarty Creative Services Limited | Arts & recreation | 2018 |
| Acumed Group Ltd | Professional & scientific | 2020 |
| Acumen Business & Compliance Limited | Financial services | 2018 |
| AD Group Limited | Administrative & support | 2016 |
| AD Levett Ltd | Information & communication | 2019 |
| ADA Hand Car Wash Ltd | Wholesale & retail | 2024 |
| Adam Joyce Content Creator Limited | Information & communication | 2026 |
| Adams & Rose Limited | Real estate | 2011 |
| Adams Marine Engineering Limited | Administrative & support | 2025 |
| Adapt to Perform Ltd | Information & communication | 2021 |
| Adapt Wellness Ltd | Other services | 2023 |
| Adaptogenic Apothecary Limited | Wholesale & retail | 2022 |
| Adaso UK Ltd | Professional & scientific | 2022 |
| ADB Properties Limited | Administrative & support | 2010 |
| Adcohealth Consultancy Limited | Professional & scientific | 2015 |
| Adcorex Ltd | Information & communication | 2025 |
| Addev Materials Aerospace Limited | Manufacturing | 2002 |
| Addev Materials UK Limited | Professional & scientific | 1996 |
| Addicus Plus Limited | Professional & scientific | 2004 |
| Addis Homes Construction Ltd | Construction | 2021 |
| Addis Homes Group Ltd | Construction | 2021 |
| Addis Homes Ltd | Construction | 2015 |
| Addisrentalpoole Ltd | Real estate | 2025 |