| Abbey Marble (East Anglia) Limited | Manufacturing | 2007 |
| Abbey Thermal Insulation Limited | Construction | 1993 |
| ABC Cladding Limited | Construction | 2020 |
| ABC Visuals Ltd | Wholesale & retail | 2021 |
| Abc-Lings & Walls Limited | Construction | 2011 |
| Abcast Engineering Limited | Extraterritorial | 2008 |
| Abdeal Properties Ltd | Real estate | 2025 |
| Abenberg Way (Brentwood) Management Co. Limited | Real estate | 1984 |
| ABF Furniture & IT Experts Ltd | Other services | 2021 |
| ABG Logistic Ltd | Transport & logistics | 2023 |
| ABI LED Limited | Manufacturing | 2025 |
| ABI Utilities Ltd | Manufacturing | 2025 |
| Abi's Catering Supplier Ltd. | Administrative & support | 1996 |
| Abiconsult Ltd | Administrative & support | 2023 |
| Abie Chikwanha Cares Ltd | Health & social care | 2013 |
| ABM Property Ltd | Real estate | 2024 |
| Abode & Beyond UK Ltd | Wholesale & retail | 2025 |
| Abode Building & Restoration Services Ltd | Construction | 2026 |
| Abound Investment Ltd | Other services | 2017 |
| Above and Beyond Care Services Ltd | Health & social care | 2023 |
| ABP Landscapes Limited | Construction | 2019 |
| ABP Oasis Ltd | Information & communication | 2023 |
| Abramova Ltd | Real estate | 2023 |
| Abrovics Medics Ltd | Health & social care | 2012 |
| ABS Building Specialist Ltd | Construction | 2022 |
| ABS Strength and Conditioning Ltd | Arts & recreation | 2025 |
| Absolute Accomodation Limited | Real estate | 2017 |
| Absolute Enforcement Limited | Other services | 2017 |
| Absolute Estate Management Limited | Real estate | 2017 |
| Absolute Harmony Limited | Health & social care | 2010 |
| Absolute Scaffolding Limited | Construction | 2015 |
| Absolute Security Management Limited | Professional & scientific | 1987 |
| Absolute UK Group Limited | Professional & scientific | 2023 |
| Absolutely Advertising Limited | Professional & scientific | 2015 |
| Absolutely Health Limited | Other services | 2024 |
| Absolutelyyours Limited | Wholesale & retail | 2019 |
| AC Electrical Services (UK) Limited | Construction | 2012 |
| Academia Consultants Ltd | Education | 2013 |
| Academy of Learning Ltd | Professional & scientific | 2024 |
| Acceber Limited | Professional & scientific | 2007 |
| Accepted Group Ltd | Professional & scientific | 2022 |
| Access Logistics Limited | Transport & logistics | 1999 |
| Accor Construction Limited | Construction | 2025 |
| Accordant Estates Company Limited | Real estate | 2018 |
| Accountax Associates Ltd | Professional & scientific | 2011 |
| Accounting Company Forpost Ltd | Professional & scientific | 2025 |
| Accurate Health Limited | Health & social care | 2024 |
| ACD Site Services Ltd | Construction | 2014 |
| Ace B Flooring Limited | Construction | 2024 |
| Ace Bathrooms Installation Limited | Construction | 2017 |
| Ace Bros Ltd | Wholesale & retail | 2019 |
| Ace Court Management Limited | Households | 2024 |
| Ace GAS Plumbing & Heating Limited | Construction | 2021 |
| Ace Group Holdings Ltd | Administrative & support | 2024 |
| Ace Impact CIC | Education | 2025 |
| Ace of Diamonds Events Limited | Arts & recreation | 2023 |
| Ace Resin Ltd | Construction | 2018 |
| Ace UK Properties Limited | Construction | 2022 |
| Ace's Electrical Limited | Construction | 2022 |
| Acibo Ltd | Manufacturing | 2025 |
| ACJ Interiors Limited | Construction | 2020 |
| ACM Abatement Limited | Water & waste | 2018 |
| Acorn Components Limited | Wholesale & retail | 2004 |
| Acorn House Developments (Basildon) Limited | Professional & scientific | 2018 |
| Acorn Property Management Essex Limited | Other services | 2015 |
| ACR Single PLY Roofing Ltd | Construction | 2023 |
| Acramans Autos Ltd | Wholesale & retail | 2026 |
| Acro Motors Ltd | Information & communication | 2024 |
| ACS Proactive Ltd | Construction | 2021 |
| Action EPC Limited | Administrative & support | 2002 |
| Actiontactic Limited | Information & communication | 1996 |
| Active Body Reformer Ltd | Arts & recreation | 2025 |
| Active Body Sgpt Ltd | Arts & recreation | 2025 |
| Active Comms Limited | Administrative & support | 2015 |
| Active Signs and Designs Ltd | Manufacturing | 2018 |
| Activeaze Ltd | Wholesale & retail | 2026 |
| Actso Limited | Other services | 2012 |
| Actual Entertainments Ltd | Arts & recreation | 2025 |
| Actual Radio Ltd | Information & communication | 2016 |
| ACW Construction (U.K) Limited | Construction | 2020 |
| AD Active Ltd | Professional & scientific | 2025 |
| AD Building & Groundworks Limited | Construction | 2014 |
| AD Care Fire and Security Ltd | Construction | 2022 |
| AD Fresh Food Ltd | Transport & logistics | 2015 |
| AD Predictive Services Limited | Other services | 2013 |
| AD World IT Ltd | Wholesale & retail | 2010 |
| ADA Catering Limited | Hospitality | 2026 |
| ADA Mechanical (U.K) Limited | Construction | 2025 |
| ADA Powers Ltd | Wholesale & retail | 2021 |
| ADA Telecoms Ltd | Information & communication | 2023 |
| Adal Drylining Ltd | Construction | 2024 |
| Adalan Ltd | Construction | 2017 |
| Adalex Global Ltd | Wholesale & retail | 2021 |
| Adam Charles & Co Ltd | Wholesale & retail | 2016 |
| Adam Gutteridge Limited | Construction | 2015 |
| Adamazi Passionate Care Ltd | Health & social care | 2023 |
| Adamek Ltd | Wholesale & retail | 2024 |
| Adamson Conservation Limited | Construction | 2011 |
| Adapt Talent Limited | Administrative & support | 2019 |
| Adaptive VR Ltd | Information & communication | 2019 |