| Allsworth Family Investments Limited | Financial services | 2017 |
| Allway Cafe Ltd | Hospitality | 2019 |
| Almaskoof Restaurant UK Limited | Hospitality | 2014 |
| Almeida Construction & Engineering Limited | Construction | 2021 |
| Almeida Star Projects Limited | Construction | 2021 |
| Almijara Limited | Real estate | 2002 |
| Alneko Properties Limited | Real estate | 2021 |
| Alora Ltd | Construction | 2014 |
| Alpac London Brands Ltd | Manufacturing | 2026 |
| Alpalmex Ltd | Health & social care | 2025 |
| Alpha & Omega MD Ltd | Professional & scientific | 2023 |
| Alpha Intelia Limited | Information & communication | 2022 |
| Alpha Property Projects Ltd | Construction | 2025 |
| Alpha Technical Solutions Ltd | Manufacturing | 2025 |
| Alpha-Focus Consultancy Ltd | Health & social care | 2020 |
| Alphabets Nursery Limited | Administrative & support | 2003 |
| Alphan Tech Solutions Ltd | Professional & scientific | 2023 |
| Alphatech Energy Limited | Professional & scientific | 2014 |
| Alpine Dwellings Ltd | Real estate | 2022 |
| Alpinesouthern Ltd | Real estate | 2024 |
| ALS Electrical Solutions Ltd | Construction | 2025 |
| Alsash Construction Ltd | Professional & scientific | 2018 |
| Alstone Properties Limited | Construction | 1973 |
| Altag LLP | | 2010 |
| ALTEMA3 Limited | Professional & scientific | 2015 |
| Altinity Ltd | Information & communication | 2017 |
| Altitude 8 Aviation Ltd | Professional & scientific | 2021 |
| Altretire Limited | Professional & scientific | 2018 |
| Altuntop Catering Ltd | Professional & scientific | 2019 |
| Altuntop Properties Ltd | Real estate | 2022 |
| Always PAY (CIS) Ltd | Administrative & support | 2018 |
| Always PAY Ltd | Administrative & support | 2018 |
| Always Scaffolding Contractors Ltd | Construction | 2025 |
| ALWAYS2G Services Limited | Other services | 2016 |
| Alyscia's Attic Limited | Wholesale & retail | 2024 |
| AM & AR Holding Limited | Real estate | 2026 |
| AM 1 Properties Holdco Limited | Financial services | 2019 |
| AM 1 Properties Ltd | Real estate | 2014 |
| AM 1 Properties Newco Limited | Financial services | 2019 |
| AM Kent Ltd | Construction | 2020 |
| AM1 Group Ltd | Financial services | 2016 |
| AM1 Residential Ltd | Real estate | 2017 |
| Amacob Ltd | Real estate | 2025 |
| Amadi Dental Limited | Extraterritorial | 2022 |
| Amarachi Iruka Ltd | Wholesale & retail | 2021 |
| Amari RAE FDN CIC | Education | 2024 |
| Amaré-Me Ltd | Other services | 2020 |
| Amatuk | Hospitality | 2004 |
| Amazing Kidz Limited | Health & social care | 2013 |
| Amazing Stuff 1 Ltd | Wholesale & retail | 2021 |
| Amazinglee Limited | Public administration | 2023 |
| Amba Accounting, Marketing & Business Advisory Limited | Professional & scientific | 2025 |
| Amberley Children’S Services Limited | Health & social care | 2025 |
| Amethyst Property Sourcing Ltd | Real estate | 2025 |
| Ameyplant Limited | Administrative & support | 2025 |
| AMG Autolocksmith Mayday Garage Ltd | Wholesale & retail | 2021 |
| Amicam Properties Ltd | Real estate | 2025 |
| Amigo Accounting and Consultancy Services Ltd | Professional & scientific | 2021 |
| Amjac Construction Limited | Construction | 2008 |
| Amorcare Supplies Limited | Wholesale & retail | 2024 |
| Amorfitness Ltd | Extraterritorial | 2024 |
| Amos House Limited | Health & social care | 2023 |
| AMR Mobile Services Limited | Administrative & support | 2023 |
| AMS Holdings (Kent) Ltd | Real estate | 2021 |
| AMS Homes Management Limited | Real estate | 2010 |
| AMS Property Services (Kent) Ltd | Households | 2020 |
| Amvisphere Limited | Administrative & support | 2026 |
| AMW Nails Limited | Wholesale & retail | 2021 |
| ANA Therapies Ltd | Health & social care | 2025 |
| Anchor Foster Care Services Limited | Health & social care | 2002 |
| Anchor Site Services Limited | Construction | 2019 |
| Anchorage Flats(Property Management)Limited(The) | Households | 1964 |
| Ancra Holdings Limited | Real estate | 2021 |
| And&Dav Ltd | Transport & logistics | 2025 |
| Andrea Berkeley Limited | Administrative & support | 2005 |
| Andrei Marcus Limited | Construction | 2020 |
| Andreiboruz Ltd | Health & social care | 2018 |
| Andrew Corcoran Ltd | Arts & recreation | 2012 |
| Andrew Harlow Ltd | Professional & scientific | 2012 |
| Andrew James Builders Ltd | Administrative & support | 2009 |
| Andrew LEE & Co Limited | Professional & scientific | 2014 |
| Andrew Proprieta Ltd | Real estate | 2022 |
| Andrews Care Angels Ltd | Health & social care | 2020 |
| Andrews Marelen Supplies Ltd | Wholesale & retail | 2011 |
| Andrews PC Systems Ltd | Other services | 2011 |
| Andrews Recruitment Group Limited | Administrative & support | 2024 |
| Andromeda Consultancy Services Limited | Administrative & support | 2002 |
| Andy Mitchell Tools Limited | Wholesale & retail | 2008 |
| Andy Payne Electrical Contractors Limited | Construction | 2021 |
| Andy Shepherd Kitchen Designer Limited | Construction | 2010 |
| Andy Shepherd Kitchens Ltd | Manufacturing | 2025 |
| Andy T Limited | Health & social care | 2015 |
| Andzama Ltd | Wholesale & retail | 2025 |
| Angel Creations International Ltd | Wholesale & retail | 2018 |
| Angelos KBB Ltd | Wholesale & retail | 2018 |
| Anglo Belgian Shipping Company Limited | Professional & scientific | 2010 |
| Angora Limited | Hospitality | 2013 |
| Ankyo Cyber Ltd | Administrative & support | 2026 |
| Anna Grant Ltd | Health & social care | 2015 |
| Anne Wayne Limited | Professional & scientific | 2013 |