| ADS Lofts and General Building Limited | Construction | 2021 |
| Adsparks Electrical Services Ltd | Construction | 2012 |
| Advance Building Control Ltd | Construction | 2022 |
| Advanced Building and Landscaping Limited | Administrative & support | 2017 |
| Advanced Drainage Technologies Ltd | Water & waste | 2022 |
| Advanced Infrastructure Solutions Ltd | Information & communication | 2015 |
| AEA Consultancy Ltd | Professional & scientific | 2025 |
| Aefs Services Limited | Public administration | 2023 |
| Aegis 2024 Ltd | Construction | 2023 |
| Afterglow Mechanical Limited | Other services | 2016 |
| AG Flooring Solutions Limited | Construction | 2023 |
| AGB Motorsport Ltd | Wholesale & retail | 2025 |
| AGC Accounting Solutions Ltd | Professional & scientific | 2025 |
| AGE Intelligence Ltd | Health & social care | 2026 |
| Agglo UK Ltd | Wholesale & retail | 2018 |
| Agile Specialist Consultancy Limited | Financial services | 2021 |
| AGL Advancement Ltd | Wholesale & retail | 2015 |
| AGS London Limited | Construction | 2022 |
| Ahhm Management Services RTM Company Limited | Households | 2023 |
| Aimtech Limited | Administrative & support | 2009 |
| Air Field Lighting Limited | Wholesale & retail | 1988 |
| Airfield Lighting Design and Training Limited | Education | 2025 |
| Airfield Lighting Systems UK Limited | Extraterritorial | 2008 |
| Airtech Analysis (UK) Ltd | Water & waste | 2016 |
| Airtightness Testing (UK) Ltd | Professional & scientific | 2007 |
| AJ Electrical Services (Essex) Ltd | Construction | 2011 |
| AJ Properties (Essex) Limited | Real estate | 2018 |
| Ajdiscounts Ltd | Wholesale & retail | 2025 |
| AJL Heating & Plumbing Ltd | Construction | 2024 |
| Ajpa Healthcare Ltd | Health & social care | 2025 |
| Ajpallets Limited | Other services | 2026 |
| AJS IT Services Limited | Information & communication | 2008 |
| AK Collective Properties Ltd | Real estate | 2026 |
| AK Cooling Solutions Limited | Energy | 2025 |
| AKB Aeronautics Limited | Construction | 2006 |
| AKR Surveying Services Limited | Professional & scientific | 2012 |
| AL Dente Coffee & Pasta Limited | Wholesale & retail | 2012 |
| AL Limos Ltd | Transport & logistics | 2022 |
| Alama MAY Pubs Limited | Hospitality | 2023 |
| Alan Boddy Accountancy Ltd | Professional & scientific | 2018 |
| Alan Neale Plumbing Services Limited | Construction | 2011 |
| Alchemy TV Limited | Administrative & support | 2011 |
| Alco Contracts Limited | Construction | 2013 |
| Alco Interiors Limited | Construction | 2013 |
| Alco Kitchens Ltd | Construction | 2023 |
| Alco Living Ltd | Wholesale & retail | 2018 |
| Alco Projects Limited | Construction | 2025 |
| Alco Property Management Ltd | Real estate | 2021 |
| Alcon Alarms Ltd | Construction | 2024 |
| Alexander Lansbury Limited | Professional & scientific | 2019 |
| Alexander Lawrence Limited | Construction | 2024 |
| Alexandra Paul Recruitment LLP | | 2016 |
| Alexandra Paul Saudi Limited | Administrative & support | 2016 |
| Alexandra Properties UK Ltd | Real estate | 2003 |
| Alexandra Road Property Ltd | Real estate | 2019 |
| Alflen Limited | Construction | 2025 |
| Algonova Limited | Real estate | 2005 |
| Align Property Finance Limited | Financial services | 2023 |
| Alisha Domestic Services Ltd | Real estate | 2026 |
| Alisha Property Management Ltd | Real estate | 2017 |
| Alisha Property Services Ltd | Construction | 2017 |
| ALL Numbers Accounting Limited | Professional & scientific | 2016 |
| ALL Numbers Limited | Professional & scientific | 2017 |
| ALL Scores Live Limited | Information & communication | 2021 |
| Allducts Contracting Services Ltd | Construction | 2025 |
| Allducts Maintenance Services Ltd | Construction | 2025 |
| Allducts Ventilation Services Limited | Construction | 2015 |
| Alley Homes Limited | Real estate | 2024 |
| Allsewpretty Ltd | Manufacturing | 2016 |
| Allstarz Productions Limited | Arts & recreation | 2016 |
| Allton Group Ltd | Real estate | 2024 |
| Allways International (Freight) Forwarding Limited | Transport & logistics | 1998 |
| Allways International Limited | Transport & logistics | 2005 |
| Alma Thermal Insulation Ltd | Manufacturing | 2018 |
| Alpert Management Limited | Professional & scientific | 2021 |
| Alpine ITC Ltd | Information & communication | 2022 |
| Alpine Pros Limited | Arts & recreation | 2018 |
| Aluminium Wheels Ltd | Wholesale & retail | 2018 |
| AM Transport 1 Ltd | Transport & logistics | 2025 |
| AMA Properties Development Ltd | Real estate | 2024 |
| Amara Collective Ltd | Professional & scientific | 2025 |
| AMB Electrical Essex Ltd | Construction | 2021 |
| Amelia Dalton: Travel by Design Limited | Administrative & support | 2004 |
| AMI One Ltd | Construction | 2014 |
| AMJ Building & Maintenance Services Limited | Construction | 2024 |
| Ammarron Limited | Real estate | 2016 |
| Ampexpresshaulage Limited | Transport & logistics | 2025 |
| Amplifier Films Limited | Information & communication | 2022 |
| Amyassists Ltd | Wholesale & retail | 2025 |
| Analytica Planning Solutions Ltd | Professional & scientific | 2025 |
| ANALYTICS4ENERGY Limited | Information & communication | 2018 |
| ANB Building Solutions Ltd | Construction | 2017 |
| Anbadaddy Management Limited | Professional & scientific | 2022 |
| Anchored Stays Ltd | Hospitality | 2025 |
| Anderson Cars Ltd | Wholesale & retail | 2025 |
| Anderson Construction (Essex) Limited | Construction | 2024 |
| Andersontopspecsurfacing Ltd | Construction | 2019 |
| Andor Systems Limited | Information & communication | 2024 |
| Andrew David Hair Limited | Other services | 2019 |
| Andrew Harvey 1971 Limited | Professional & scientific | 2021 |