| Aesthetic Web Limited | Professional & scientific | 2025 |
| AET INT Ltd | Administrative & support | 2013 |
| Agility Technology Services Limited | Information & communication | 2013 |
| Aidibe Limited | Wholesale & retail | 2025 |
| Air Conditioning Materials Ltd | Extraterritorial | 2006 |
| Air Drone Surveying Ltd | Professional & scientific | 2021 |
| Air Eco Ltd | Manufacturing | 2023 |
| Airbtics Ltd | Information & communication | 2019 |
| Airtemp A.C. Ltd | Administrative & support | 2004 |
| Airtemp Air Conditioning Ltd | Extraterritorial | 2006 |
| Airtemp Service Ltd | Extraterritorial | 2006 |
| Ajcl Group Ltd | Transport & logistics | 2018 |
| Ajra Ltd | Real estate | 2021 |
| Albert Hall Crescent LLP | | 2012 |
| Albion Supplies Ltd | Wholesale & retail | 2006 |
| Albo ST Leonards Ltd | Hospitality | 2023 |
| Alderon Ventures Ltd | Wholesale & retail | 2026 |
| Alenanna Ltd | Health & social care | 2014 |
| Alexander James Financial Planning Limited | Financial services | 2011 |
| Algodón Limited | Wholesale & retail | 2019 |
| Aligned Compliance Consulting Limited | Professional & scientific | 2025 |
| Aline Shareholders Limited | Financial services | 2014 |
| ALL C&J Ltd | Wholesale & retail | 2024 |
| ALL Great Solutions Ltd | Health & social care | 2021 |
| ALL Pro Roofing Specialists Ltd | Construction | 2026 |
| Allaboutthatsmash Ltd | Hospitality | 2025 |
| Almoss Ltd | Wholesale & retail | 2025 |
| Alpine House Management Company Limited | Households | 2004 |
| Altrade Solution Ltd | Construction | 2023 |
| Amalfi Estates Limited | Construction | 2023 |
| Amanda Dormon Limited | Arts & recreation | 2006 |
| Amanda Thomas Ltd | Professional & scientific | 2020 |
| Amandre Wilson Limited | Professional & scientific | 2020 |
| Amberwood Management Company (Hastings) Limited | Households | 2000 |
| Ameeva Properties Ltd | Real estate | 2025 |
| Amelia-Wessing Ltd. | Real estate | 2018 |
| Ameri Group Ltd | Water & waste | 2024 |
| Ameri Properties Limited | Real estate | 2025 |
| AMY Fuller Ltd | Health & social care | 2019 |
| Amy's Awesome Avon Shop Ltd | Wholesale & retail | 2026 |
| Amygdala Home Ltd | Manufacturing | 2021 |
| Anglesea Mansions RTM Company Limited | Households | 2024 |
| Anglesea Terrace Estate Ltd | Real estate | 2015 |
| ANJ Advisors Ltd | Financial services | 2025 |
| Anne Care Consultancy Ltd | Professional & scientific | 2024 |
| Anonymous Research & Consultancy Ltd | Professional & scientific | 2024 |
| Another Project @ NO2 Ltd | Hospitality | 2024 |
| Ansell Building Ltd | Construction | 2021 |
| Anton Fried Chicken Ltd | Hospitality | 2026 |
| AO Carpentry & Joinery Limited | Manufacturing | 2024 |
| Apersu Ltd | Professional & scientific | 2024 |
| Apothecary Cafe RYE Ltd | Hospitality | 2024 |
| Apps and Children Ltd | Wholesale & retail | 2020 |
| Archifact Limited | Professional & scientific | 2010 |
| Architourian Limited | Administrative & support | 2024 |
| Argus Robotics Ltd | Manufacturing | 2026 |
| Aries Medical Services Ltd | Health & social care | 2021 |
| Arka Music Ltd | Arts & recreation | 2024 |
| Arleth Health Ltd | Health & social care | 2015 |
| Aron Razvan Limited | Health & social care | 2017 |
| Art Lending Library Ltd | Wholesale & retail | 2024 |
| Arta by the Sea Ltd | Hospitality | 2026 |
| Artisan Cards Limited | Wholesale & retail | 2006 |
| Artisvin Limited | Wholesale & retail | 2013 |
| Artomobile Ltd. | Professional & scientific | 2011 |
| Ascent Rigging and Construction Services Ltd. | Administrative & support | 2018 |
| Asletts Limited | Construction | 2013 |
| Aspects Project Management Limited | Construction | 2020 |
| Assist Point UK Ltd | Professional & scientific | 2026 |
| Associated Commercial Enterprises Ltd | Administrative & support | 2019 |
| Asti Group Ltd | Wholesale & retail | 2022 |
| AT Home Services Group Limited | Construction | 2025 |
| AT Home Services Ltd | Construction | 2017 |
| ATB 2021 Bidco Limited | Financial services | 2021 |
| ATB 2021 Midco Limited | Financial services | 2021 |
| ATB 2021 Topco Limited | Financial services | 2021 |
| Atom Tree Surgery Ltd | Agriculture & fishing | 2008 |
| Atum Labs Ltd | Information & communication | 2026 |
| Aukuma Limited | Administrative & support | 2022 |
| Aurevista Ltd | Information & communication | 2026 |
| Aurygen Ltd | Information & communication | 2025 |
| Authentic Nourishment Ltd | Hospitality | 2025 |
| Avanti (ABI) Ltd | Health & social care | 2011 |
| Aventex Dental LAB Ltd | Manufacturing | 2023 |
| AVM Trading and Consulting Ltd | Professional & scientific | 2019 |
| Avon Court(St.Leonards-On-Sea)Management Company | Households | 1964 |
| Ayrforce Studio Limited | Wholesale & retail | 2022 |
| B Socials Ltd | Information & communication | 2023 |
| B.Stevens Plumbing & Heating Ltd | Construction | 2024 |
| Babhomes Ltd | Households | 2026 |
| Bahnfinds Limited | Wholesale & retail | 2023 |
| BAJ Dominik Ltd | Transport & logistics | 2013 |
| Baker Architectural Ltd | Professional & scientific | 2014 |
| Balanga Ltd | Real estate | 2021 |
| Baldslow Property Services Limited | Real estate | 2002 |
| Bale House CAD Limited | Professional & scientific | 1996 |
| Balmoral House (TW) RTM Company Limited | Real estate | 2013 |
| Balmy COW Ltd | Wholesale & retail | 2025 |
| Bang Industries Ltd | Manufacturing | 2025 |
| Bangkok Delivery BOY Limited | Hospitality | 2023 |