| Ampersand Brands Limited | Professional & scientific | 2011 |
| Ampersand Consulting Ltd | Professional & scientific | 2024 |
| Amplio Consulting Ltd | Professional & scientific | 2012 |
| Ampm Block Management Limited | Households | 2022 |
| Amps News Limited | Wholesale & retail | 2003 |
| Amrp Limited | Real estate | 2022 |
| Amsa Properties UK Limited | Real estate | 2025 |
| AMW Group Limited | Real estate | 2017 |
| AMY Addison Limited | Arts & recreation | 2021 |
| AN1TA Ltd | Extraterritorial | 2020 |
| Anagen Hair Limited | Wholesale & retail | 2003 |
| Analyst Group Limited | Extraterritorial | 2025 |
| ANASTAS1A Limited | Extraterritorial | 2020 |
| Anderbay Limited | Hospitality | 2021 |
| Anderson Douglas Ltd | Real estate | 2024 |
| Anderson Family Holdings Limited | Financial services | 2025 |
| Anderson MAC Limited | Professional & scientific | 2007 |
| Anderson Reed Limited | Administrative & support | 2024 |
| Andisa IT Consultants Ltd | Information & communication | 2003 |
| Andrew Atkinson Haulage Limited | Transport & logistics | 1997 |
| Andrew Makin Properties Ltd | Real estate | 2023 |
| Andrew Mawson Limited | Manufacturing | 2003 |
| Andrew Nattrass Joinery Limited | Construction | 2012 |
| Andrex Limited | Extraterritorial | 2011 |
| Andy Paine Consulting Ltd | Professional & scientific | 2024 |
| Andy Willis Property Services Ltd | Construction | 2020 |
| Andyinthecloud Consulting Ltd | Information & communication | 2025 |
| Anetica Limited | Real estate | 2014 |
| Ange Pitta Star Ltd | Hospitality | 2024 |
| Angel Guardian Limited | Extraterritorial | 2011 |
| Angela Gregory Ltd | Health & social care | 2017 |
| Angela Swift Care (Southport) Limited | Health & social care | 2025 |
| Angela Swift Developments (Gomersal) Limited | Construction | 2025 |
| Angela Swift Developments (Southport) Limited | Construction | 2024 |
| Angela Swift Developments (Stainton) Limited | Construction | 2017 |
| Angela Swift Developments (Worsley) Ltd | Construction | 2024 |
| Angela Swift Developments Group Limited | Financial services | 2015 |
| Angela Swift Properties Limited | Extraterritorial | 2017 |
| Angelic Sounds Limited | Arts & recreation | 2000 |
| Angie Snow Ltd | Hospitality | 2019 |
| Animal Health JOB Site Ltd | Information & communication | 2024 |
| Animex International Limited | Extraterritorial | 2015 |
| ANN Reynolds Home Economist Ltd | Hospitality | 2011 |
| ANN1E Limited | Extraterritorial | 2020 |
| Anna Ceder Selection Ltd | Administrative & support | 2016 |
| Anna's Simply Clean Ltd | Administrative & support | 2022 |
| Anoa Group Limited | Construction | 2020 |
| Another Wave C.I.C. | Education | 2020 |
| Anphini Limited | Real estate | 2018 |
| Anson Hewlett Limited | Extraterritorial | 2025 |
| Antalya Starbeck Barber Limited | Other services | 2024 |
| Anthony Jones Electrical Limited | Construction | 2008 |
| Antiope Management Limited | Professional & scientific | 2020 |
| Anumi Group Ltd | Professional & scientific | 2024 |
| Anxious Limited | Wholesale & retail | 2020 |
| AP Michaelson Limited | Information & communication | 2014 |
| AP Property 2026 Ltd | Real estate | 2025 |
| APB Property Maintenance Limited | Construction | 2023 |
| Apex Innovations for Trade Ltd | Wholesale & retail | 2025 |
| Apex Medical Group LLP | | 2026 |
| Apex Performance Parts Limited | Wholesale & retail | 2002 |
| Apex Salons Academies Limited | Education | 2025 |
| Apex Salons Harrogate Limited | Other services | 2022 |
| Apex Salons Holdings Limited | Other services | 2025 |
| Apex Salons Roundhay Limited | Other services | 2025 |
| Apex Salons Wetherby Limited | Other services | 2025 |
| Apex Vision International Traiding Ltd | Wholesale & retail | 2024 |
| Apini Limited | Information & communication | 2019 |
| APL Joinery Ltd | Construction | 2017 |
| Apmcc Ltd | Construction | 2014 |
| Apollo Capital Asset Holdings Ltd | Real estate | 2026 |
| Apollo Capital Group Holdings Ltd | Financial services | 2025 |
| Apollo Capital Group Ltd | Financial services | 2020 |
| Apollo Car Finance Limited | Financial services | 2021 |
| Apparel Inspired Ltd | Professional & scientific | 2023 |
| Appeal P.R. Limited | Administrative & support | 2003 |
| Appleby Jones Limited | Wholesale & retail | 2025 |
| Applegate Care Limited | Health & social care | 2025 |
| Applegate Court Limited | Health & social care | 2025 |
| Appleton Finn Limited | Administrative & support | 2021 |
| Approach AI Ltd | Professional & scientific | 2025 |
| Apricitie Ltd | Health & social care | 2011 |
| Apricot Software Solutions Limited | Information & communication | 2014 |
| Apro Media Ltd | Information & communication | 2026 |
| Apto Business Interiors Limited | Construction | 2026 |
| Aptus MEP Ltd | Professional & scientific | 2021 |
| Aqua Consultants Limited | Administrative & support | 2008 |
| Aqua Deva Ltd | Wholesale & retail | 2024 |
| Aqua Development Services North, Ltd | Construction | 2020 |
| Aqua Fire Ltd | Public administration | 2011 |
| Aqua Silva Catering Ltd | Hospitality | 2017 |
| Aqueous 1ST Kwikflow Limited | Administrative & support | 1998 |
| AR Industries Limited | Professional & scientific | 2022 |
| AR1EL Limited | Extraterritorial | 2020 |
| Arapaho Limited | Professional & scientific | 2003 |
| Arbor Medical Limited | Health & social care | 2023 |
| ARC Analyst Resource & Consulting Limited | Professional & scientific | 2006 |
| ARC Capital Group Ltd | Financial services | 2022 |
| ARC Commercial Energy Services Limited | Extraterritorial | 2024 |
| ARC Commercial Energy Solutions Limited | Extraterritorial | 2024 |