| American Theme Events Limited | Arts & recreation | 1995 |
| Amesglobalunited Ltd | Wholesale & retail | 2019 |
| Amesis Ltd | Administrative & support | 2006 |
| Amess & Gilham Limited | Agriculture & fishing | 2018 |
| Ametis Homes Ltd | Health & social care | 2023 |
| AMG Facilities Management Ltd | Manufacturing | 2016 |
| AMG Trans 78 Ltd | Transport & logistics | 2019 |
| Amhunt Ltd | Administrative & support | 2025 |
| Amiani Limited | Professional & scientific | 2020 |
| Amigoit Ltd | Information & communication | 2013 |
| Amis Estates Ltd | Hospitality | 2023 |
| AMJ Industrial Services Limited | Manufacturing | 2014 |
| Amore PS Ltd | Hospitality | 2026 |
| Amoure Hair Ltd | Wholesale & retail | 2026 |
| Amplified SEO Limited | Other services | 2025 |
| AMR Maintenance Services Limited | Construction | 2019 |
| Amr-O Education Ltd | Education | 2021 |
| Amruth Gali Solutions Ltd | Information & communication | 2025 |
| AMS Quality Meats Ltd | Wholesale & retail | 2024 |
| Amsbury Consulting Limited | Professional & scientific | 2018 |
| Amsbury Storage & Packing Limited | Manufacturing | 2004 |
| Amson Solutions Ltd | Professional & scientific | 2014 |
| Amtech Smart Surveillance Ltd | Administrative & support | 2019 |
| Amtt LLP | | 2016 |
| AMY Seymour Interiors Ltd | Professional & scientific | 2024 |
| AN Electrical and Design Solutions Ltd | Construction | 2025 |
| AN Englishrose Limited | Extraterritorial | 2013 |
| AN Origin Ltd | Construction | 2012 |
| AN Tyres & Company Ltd | Wholesale & retail | 2020 |
| Anab Creative Solutions Ltd | Wholesale & retail | 2018 |
| Anajeasy Ltd | Hospitality | 2026 |
| Analogic UK II Ltd | Manufacturing | 2023 |
| Anastasia’S Green Company Ltd | Wholesale & retail | 2021 |
| Anbaric Electrical Ltd | Construction | 2017 |
| Anchor Digital Services Limited | Information & communication | 2026 |
| Anchorpath Care Ltd | Health & social care | 2026 |
| Anderida Media Limited | Other services | 2015 |
| Anderson Building & Construction Ltd | Construction | 2021 |
| Anderson Management Solutions Limited | Construction | 2001 |
| Anderson North Limited | Professional & scientific | 2013 |
| Anderson Phillips Limited | Extraterritorial | 1997 |
| Anderway Construction Limited | Construction | 2024 |
| Andles Property Management Limited | Households | 2017 |
| Andprestcom Limited | Wholesale & retail | 2021 |
| Andrada Beauty Limited | Other services | 2024 |
| Andrea Pickard Coaching Ltd | Other services | 2020 |
| Andrew Appiah & Co Consultancy Services Limited | Education | 2016 |
| Andrew Barr and SON Limited | Agriculture & fishing | 1961 |
| Andrew Gormley Surveying Services Ltd | Construction | 2013 |
| Andrew Hammond Art Limited | Information & communication | 2015 |
| Andrew Morgan Watches Ltd | Information & communication | 2023 |
| Andrew Powell Corporate Solutions Limited | Financial services | 2018 |
| Andrew RAY Investments Ltd | Real estate | 2018 |
| Andrew RAY Mortgages Ltd | Financial services | 2018 |
| Andrew TRANS86 Ltd | Transport & logistics | 2018 |
| Andrius Dmb&Co Ltd | Transport & logistics | 2019 |
| Andy’S Food Factory Ltd | Hospitality | 2019 |
| Angel Detailing Ltd | Manufacturing | 2019 |
| Angel Zhen Limited | Hospitality | 2022 |
| Angel's Independent Family Funerals Limited | Other services | 2010 |
| Angie and Matt Weddings Limited | Hospitality | 2023 |
| ANI Management Services, Limited | Administrative & support | 2021 |
| Animals for Autism | Health & social care | 2025 |
| Animalscan Limited | Agriculture & fishing | 1999 |
| Animalweb Ltd | Information & communication | 2020 |
| Animation Studio Limited | Information & communication | 1986 |
| Ani’S Tech Repairs Ltd | Manufacturing | 2025 |
| ANK Courier Service Ltd | Transport & logistics | 2020 |
| Anmar Ltd | Real estate | 2020 |
| Anna Lisa Boccia Languages Services Ltd | Professional & scientific | 2007 |
| Annabel Tucker Counselling Ltd | Other services | 2022 |
| ANNEXE@13EVENTS Ltd | Administrative & support | 2026 |
| Annie Atelier Ltd | Manufacturing | 2026 |
| Anorplus Ltd | Public administration | 2025 |
| Anorra Care Ltd | Health & social care | 2025 |
| Another Creative Entity Ltd | Wholesale & retail | 2023 |
| Another Mother Management Limited | Other services | 2021 |
| Answift Limited | Households | 2015 |
| Anthony & Grace Trade HUT Limited | Wholesale & retail | 2017 |
| Anthony James Services Ltd | Professional & scientific | 2025 |
| Anthonypillai Ltd | Health & social care | 2023 |
| Antiagenda Limited | Professional & scientific | 2025 |
| Anto&Teo Limited | Transport & logistics | 2019 |
| Antzs Business Services Limited | Administrative & support | 2018 |
| Antzs PVT Ltd | Arts & recreation | 2016 |
| Anupari Medical Imaging Ltd | Health & social care | 2014 |
| Anura Limited | Information & communication | 2026 |
| ANV Building Construction Ltd | Construction | 2019 |
| Anvile Project Management Limited | Construction | 2026 |
| Anvina Product Ltd | Wholesale & retail | 2022 |
| AO Capital Ltd | Administrative & support | 2026 |
| AOJ Property Developments Ltd | Real estate | 2023 |
| Aonb Limited | Real estate | 2004 |
| Aooa Properties Limited | Real estate | 2023 |
| AP Gentry Consulting Limited | Information & communication | 2014 |
| AP Media Tech Ltd | Professional & scientific | 2025 |
| AP Mining Group Ltd | Professional & scientific | 2016 |
| AP Wellbeing Ltd | Other services | 2011 |
| APB Properties Limited | Real estate | 1998 |
| Apeiron Philanthropy Limited | Professional & scientific | 2017 |