| 9Y Funding 1 Limited | Financial services | 2023 |
| 9Y Funding 2 Limited | Financial services | 2023 |
| 9Y Holdings Limited | Financial services | 2023 |
| 9Y Techco Limited | Information & communication | 2026 |
| @ Architect (UK) Limited | Professional & scientific | 2012 |
| A & F Meats Limited | Wholesale & retail | 2009 |
| A & M Allround Property Maintenance Limited | Construction | 2017 |
| A & M Services (Essex) Ltd | Construction | 2015 |
| A & N (Clothing & Camping) Limited | Wholesale & retail | 1995 |
| A & S Supermarket Brentwood Ltd | Wholesale & retail | 2026 |
| A 406 Cafe Ltd | Hospitality | 2014 |
| A Alexander Tutoring Ltd | Education | 2013 |
| A B COM Ltd | Households | 2019 |
| A Clarke Commercial Services Limited | Professional & scientific | 2017 |
| A DO Z Essex Limited | Construction | 2018 |
| A Etemadi Ltd | Health & social care | 2026 |
| A Gowing Limited | Professional & scientific | 2003 |
| A Grainger Transport Ltd | Transport & logistics | 2009 |
| A J Electrical (Brentwood) Ltd | Construction | 2005 |
| A J P Consultancy Ltd | Extraterritorial | 2001 |
| A Kilian Services Ltd | Construction | 2011 |
| A Leaner Fit Ltd | Administrative & support | 2016 |
| A Morrissey & Associates Limited | Professional & scientific | 2021 |
| A P Construction (UK) Ltd | Construction | 2012 |
| A P Construction UK Group Ltd | Construction | 2026 |
| A P Property Services (UK) Ltd | Real estate | 2016 |
| A Phillips Media Limited | Professional & scientific | 2024 |
| A S Webb Design and Build Ltd | Other services | 2017 |
| A Shah Optical Ltd | Professional & scientific | 2019 |
| A Tidy Mind London Limited | Other services | 2019 |
| A White Meats Limited | Wholesale & retail | 2015 |
| A Word in Your Shell-Like Ltd | Administrative & support | 2014 |
| A&K Transport UK Ltd | Transport & logistics | 2008 |
| A&M Maintenance Experts Ltd | Construction | 2019 |
| A&V Mechanical Services Limited | Construction | 2024 |
| A&V Patterson Properties Limited | Real estate | 2025 |
| A&X Developments Ltd | Construction | 2026 |
| A-List Card UK Limited | Arts & recreation | 2024 |
| A-Source Plumbing Ltd | Construction | 2011 |
| A. Whalebone Building Supplies Ltd. | Wholesale & retail | 1993 |
| A.Blake Construction Ltd | Construction | 2024 |
| A.H Elec Ltd | Construction | 2026 |
| A.J. Alexander Ltd | Arts & recreation | 2019 |
| A.M. Shipping Limited | Transport & logistics | 1992 |
| A.M.A. Accommodation Ltd | Real estate | 2021 |
| A.W.Entertainments Ltd | Arts & recreation | 2022 |
| A.W.May.Limited | Professional & scientific | 1931 |
| A1 MOT & Servicing Ltd | Professional & scientific | 2025 |
| A1 Seafoods Limited | Wholesale & retail | 2000 |
| A2O Group Limited | Other services | 2018 |
| A2O Limited | Construction | 2001 |
| A2O Site Services Limited | Construction | 2015 |
| A3E Catering Ltd | Construction | 2023 |
| A3E Ltd | Construction | 2025 |
| A3E Racing Ltd | Wholesale & retail | 2023 |
| A3E Technologies Ltd | Information & communication | 2024 |
| AA Cottages Ltd | Real estate | 2023 |
| AA Trading Limited | Hospitality | 2014 |
| Aapok Limited | Manufacturing | 2025 |
| Aashv Ltd | Construction | 2024 |
| AAT (2025) Limited | Construction | 2010 |
| AB Design London Ltd. | Administrative & support | 2016 |
| ABA Connect Limited | Education | 2015 |
| Abaco-Enterprise Ltd | Administrative & support | 2016 |
| Abacus AC Solutions Ltd | Construction | 2011 |
| Abacus Air Conditioning Ltd | Energy | 2018 |
| Abacus Contracts (ACL) Limited | Construction | 2004 |
| Abacus Data and Mailing Limited | Administrative & support | 2010 |
| Abacus Wealth Planning Ltd. | Financial services | 1986 |
| Abbots Construction Management Ltd | Construction | 2015 |
| Abbotts Floor & Wall Designs Limited | Construction | 2010 |
| Abel and Eden Ltd | Professional & scientific | 2022 |
| Able Home Asbestos Surveys Ltd | Professional & scientific | 2020 |
| Able Partywall Surveyors Limited | Professional & scientific | 2020 |
| Able Surveyors Limited | Professional & scientific | 2014 |
| ABLE2BRIDGE Ltd | Real estate | 2016 |
| Ablecross Limited | Health & social care | 2016 |
| Ablemare Properties Limited | Real estate | 2006 |
| Ableprize Limited | Financial services | 2004 |
| ABM 2021 Limited | Professional & scientific | 2017 |
| Abraham Blacksmith Ltd | Health & social care | 2012 |
| Absolute Accountancy Ltd | Professional & scientific | 2024 |
| Absolute Licence Solutions Limited | Professional & scientific | 2019 |
| Absolute Renovation Limited | Construction | 2018 |
| Abura Limited | Professional & scientific | 2006 |
| AC Consulting Ltd | Other services | 2024 |
| AC Financial Recruitment Limited | Administrative & support | 1994 |
| Acanthus Interior Design Limited | Other services | 2008 |
| Access Events Ltd | Professional & scientific | 2022 |
| Accounts Bookkeeping and Payroll (UK) Limited | Professional & scientific | 2015 |
| Accutrainee Limited | Administrative & support | 2010 |
| Ace BC Limited | Other services | 2015 |
| Ace Contracts Limited | Construction | 1999 |
| Ace Internet Limited | Information & communication | 2023 |
| Ace Maintenance (Air Conditioning) Limited | Energy | 2024 |
| Ace Warehousing Logistics (UK) Ltd | Administrative & support | 2016 |
| Acelinedirect Ltd | Wholesale & retail | 2024 |
| Acheron Packet Ltd | Construction | 2025 |
| Acid Jazz Acquisitions Ltd | Wholesale & retail | 2019 |
| Acid Jazz Records Limited | Arts & recreation | 1991 |