| Amca Fitness Limited | Administrative & support | 2024 |
| Amcb Services Limited | Professional & scientific | 2024 |
| Amcl Property Holdings Ltd | Real estate | 2025 |
| Amdp Limited | Professional & scientific | 2009 |
| Amear Limited | Hospitality | 2021 |
| Amear Sufyan Limited | Hospitality | 2021 |
| Ameens Limited | Hospitality | 2014 |
| Ameens Pizzas Ltd | Hospitality | 2018 |
| AMEENS1 Ltd | Manufacturing | 2025 |
| Ameer Academy Ltd | Other services | 2023 |
| Amen Properties Ltd | Real estate | 2022 |
| American Chews Limited | Wholesale & retail | 2024 |
| Amethyst Literary Limited | Information & communication | 2025 |
| Amethyst Property Developments Limited | Construction | 2023 |
| Ametrine Aesthetics Ltd | Education | 2020 |
| Ameya Properties Limited | Real estate | 2023 |
| Ameya Travel Limited | Administrative & support | 2024 |
| Amhm Holdco Limited | Financial services | 2022 |
| AMI Lillybet Ltd | Arts & recreation | 2024 |
| Amica Vina Ltd | Administrative & support | 2025 |
| Amicable Technologies Limited | Wholesale & retail | 2022 |
| Amicis Homes Ltd | Construction | 2017 |
| Amigos Cleaning Limited | Construction | 2024 |
| Amina ALI Ltd | Wholesale & retail | 2017 |
| Amina ALI Properties Ltd | Real estate | 2024 |
| Amir Nest Ltd | Wholesale & retail | 2025 |
| Amir Tandoori Ltd | Hospitality | 2020 |
| Amira Express Ltd | Hospitality | 2026 |
| Amjax Residential Ltd | Real estate | 2019 |
| AMK Consultants Limited | Health & social care | 2023 |
| Amksons Ltd | Wholesale & retail | 2021 |
| Amlani Investments Limited | Financial services | 2025 |
| AMM Automotive Works Ltd | Wholesale & retail | 2026 |
| Ammarm (UK) Ltd | Information & communication | 2011 |
| Ammarm Ltd | Information & communication | 2006 |
| Ammonite Design Studios Ltd | Information & communication | 2012 |
| Ammp Stores Ltd | Wholesale & retail | 2026 |
| AMO Property Group Ltd | Real estate | 2025 |
| Amora Creations Ltd | Arts & recreation | 2025 |
| Amoxon Ltd | Wholesale & retail | 2026 |
| Ampere Property Investments Ltd | Construction | 2026 |
| Amplify Hire Limited | Administrative & support | 2019 |
| Ampm Twenty Four Seven Limited | Information & communication | 2014 |
| Amrp Consulting Limited | Professional & scientific | 2017 |
| AMS Autotrade Limited | Wholesale & retail | 2020 |
| AMS Equine Limited | Transport & logistics | 2024 |
| AMS Vehicle Services Ltd | Wholesale & retail | 2023 |
| Amsg Consulting Ltd | Information & communication | 2022 |
| Amsin Ltd | Health & social care | 2020 |
| AMT Health Ltd | Health & social care | 2021 |
| Amtech Automated Micro Technology Limited | Manufacturing | 1998 |
| AMV Owners Club Ltd | Other services | 2023 |
| AMW Training Ltd | Professional & scientific | 2024 |
| AMY Fowler Clinical Psychology Ltd | Health & social care | 2019 |
| AMY Louise Aesthetics & Beauty Limited | Other services | 2022 |
| AMY Mitchell Beauty Ltd | Other services | 2014 |
| AMY Ormston Coaching Limited | Health & social care | 2019 |
| AMY Wilson Cosmetic Studio Ltd | Other services | 2019 |
| AMZ Couriers Ltd | Transport & logistics | 2020 |
| Amzora Prep Solutions Limited | Wholesale & retail | 2026 |
| An's Supermarket Limited | Wholesale & retail | 2016 |
| An:Artists Information Company | Information & communication | 1982 |
| ANA Clean Limited | Households | 2013 |
| ANA& EDY Cleaning Ltd | Administrative & support | 2023 |
| Analyticsguard.Ai Ltd | Information & communication | 2024 |
| ANC Consultancy Limited | Information & communication | 2009 |
| Anchor Point Marine Survey Ltd | Transport & logistics | 2018 |
| Anchor Vision Ltd | Wholesale & retail | 2025 |
| Anchorage (HSG) Limited | Financial services | 2019 |
| Ancient Days Venison Limited | Wholesale & retail | 2020 |
| Ancilla Concierge Ltd | Professional & scientific | 2023 |
| Anclote Ltd | Real estate | 2019 |
| Ancor Investment Group Limited | Real estate | 2021 |
| AND Europe Ltd | Information & communication | 2013 |
| AND REU Ltd | Real estate | 2025 |
| AND+ Studios Ltd | Professional & scientific | 2021 |
| And-Trac Ltd | Wholesale & retail | 2013 |
| Andbeth Limited | Real estate | 2025 |
| Ande Standardz Ltd | Wholesale & retail | 2025 |
| Anderson & Garland Holdco Limited | Administrative & support | 2017 |
| Anderson & Garland Limited | Wholesale & retail | 1992 |
| Anderson Bros. (Prestwick Farm) Limited | Professional & scientific | 1984 |
| Anderson Electric Ltd | Construction | 2024 |
| Anderson HV Ltd | Construction | 2020 |
| Andojem Limited | Other services | 2011 |
| Andrea Ponting Ltd | Hospitality | 2025 |
| Andrei Serv Limited | Transport & logistics | 2023 |
| Andrew & Andrew Holdings Limited | Financial services | 2025 |
| Andrew Cartwright Football Coaching Ltd | Arts & recreation | 2021 |
| Andrew Doyle Business Limited | Wholesale & retail | 2026 |
| Andrew Hughes Utility Services Ltd | Construction | 2009 |
| Andrew Jackman Properties Ltd | Real estate | 2016 |
| Andrew James Bowey Limited | Health & social care | 2022 |
| Andrew Pears Consulting Limited | Information & communication | 2007 |
| Andrew Robson Limited | Other services | 2009 |
| Andrew Taylor Consulting Ltd | Professional & scientific | 2026 |
| Andrews & Scott Limited | Professional & scientific | 2013 |
| Andy & Linda Limited | Hospitality | 2013 |
| Andy Frain Services UK Limited | Administrative & support | 2015 |
| Andy Knell Holdings Limited | Financial services | 2021 |