| Auckland Care Limited | Administrative & support | 2007 |
| Auckland Investments Ltd | Real estate | 2026 |
| Auctio Limited | Professional & scientific | 2026 |
| Auction Central Limited | Extraterritorial | 2011 |
| Auction Wars Ltd | Wholesale & retail | 2015 |
| Auctiononline.Bid Ltd | Wholesale & retail | 2018 |
| AUD Consultants Ltd | Administrative & support | 2022 |
| Audacia Hearing UK Ltd | Wholesale & retail | 2025 |
| Audde Global Resources Limited | Hospitality | 2025 |
| Audemars Corporate Risk Solutions Ltd | Financial services | 2013 |
| Auden Court Management Company Limited | Households | 2005 |
| Audere Medical Services Limited | Health & social care | 2001 |
| Auderes Advisory Ltd | Information & communication | 2024 |
| Audibear Limited | Information & communication | 2026 |
| Audio Delight Limited | Extraterritorial | 2009 |
| Audio Technical Services Ltd. | Professional & scientific | 2009 |
| Audio Visual Innovations Ltd | Professional & scientific | 2019 |
| Audio Visual Technology Solutions (UK) Limited | Wholesale & retail | 2012 |
| AUDIO123 Limited | Wholesale & retail | 2012 |
| Auditune Ltd | Information & communication | 2024 |
| Audivise Services Limited | Wholesale & retail | 2025 |
| Audley Films LLP | | 2004 |
| Audos Limited | Professional & scientific | 1996 |
| Audrey Estates Limited | Real estate | 2023 |
| Aufait Solutions Ltd | Information & communication | 2015 |
| AUG Management Limited | Extraterritorial | 2007 |
| Aughaloor Advisory Ltd | Professional & scientific | 2026 |
| Augmented Lifestyle CIC | Arts & recreation | 2022 |
| August Arts Limited | Wholesale & retail | 2025 |
| August Play Limited | Arts & recreation | 2026 |
| Augusta Consulting Ltd | Professional & scientific | 2026 |
| Augustus Bradford Ltd | Real estate | 2017 |
| Augustus Court RTM Company Limited | Households | 2006 |
| Augustus Estates Ltd | Real estate | 2019 |
| Augustus Services Ltd | Construction | 2022 |
| Augustus Solutions Midlands Ltd | Other services | 2023 |
| AUH Properties Limited | Real estate | 2024 |
| Aujen Limited | Other services | 2009 |
| Aujla & Mann Ltd | Wholesale & retail | 2009 |
| Aujla Convenience Store Ltd | Wholesale & retail | 2025 |
| Aujla Transporter Ltd | Transport & logistics | 2025 |
| AUK Community Services Ltd | Wholesale & retail | 2025 |
| AUK Global Ltd | Wholesale & retail | 2025 |
| AUK Organisation Ltd | Information & communication | 2025 |
| Aukhad Limited | Health & social care | 2025 |
| Aulak Fashions Limited | Wholesale & retail | 2018 |
| Aulakh Holdings (Solihull) Ltd | Financial services | 2021 |
| Aulakh Holdings Ltd | Financial services | 2018 |
| Aulakh Housing Limited | Real estate | 2025 |
| Aulakh Property Investments Limited | Real estate | 2022 |
| Aulakh Property Limited | Real estate | 2021 |
| Aulakh Transport Ltd | Transport & logistics | 2024 |
| Auld Omens Ltd | Arts & recreation | 2024 |
| Auldin Anaesthetic Services Ltd | Health & social care | 2020 |
| AUM Property Investments Ltd | Real estate | 2005 |
| AUM77 Ltd | Professional & scientific | 2024 |
| Aumber Properties Ltd | Real estate | 2023 |
| Aumber Property Limited | Real estate | 2025 |
| Aumovio Holdings UK Limited | Administrative & support | 2000 |
| Aumovio UK Limited | Manufacturing | 1970 |
| Aunt Dows Limited | Hospitality | 2018 |
| Aunt Sally's (Birmingham) Ltd | Wholesale & retail | 2013 |
| Auntie Jollof Ltd | Hospitality | 2026 |
| Auntie's Special Dumplings Kitchen Ltd | Hospitality | 2025 |
| Aunty She's Daycare Ltd | Health & social care | 2024 |
| Aupgo Limited | Professional & scientific | 2022 |
| AUR90 Limited | Transport & logistics | 2025 |
| Aura & Arivon Hair & Beauty Training Academy Ltd | Other services | 2021 |
| Aura Birmingham Events Ltd | Administrative & support | 2019 |
| Aura Care - EAR WAX Removal Specialist Ltd | Wholesale & retail | 2022 |
| Aura Desserts Ltd | Hospitality | 2020 |
| Aura E-Commerce Ltd | Wholesale & retail | 2025 |
| Aura Entertainment Ltd | Wholesale & retail | 2025 |
| Aura Fightwear Ltd | Wholesale & retail | 2025 |
| Aura Fitness Centre Limited | Health & social care | 2023 |
| Aura Gold Ltd | Wholesale & retail | 2024 |
| Aura Hotel Group Limited | Real estate | 2025 |
| Aura Indian Cuisine Limited | Hospitality | 2024 |
| Aura Lettings & Stays Ltd Limited | Hospitality | 2025 |
| Aura Lounge Birmingham Ltd | Hospitality | 2019 |
| Aura MMA Ltd | Arts & recreation | 2021 |
| Aura Motor Cars Limited | Wholesale & retail | 2026 |
| Aura Origin Ltd | Wholesale & retail | 2022 |
| Aura Property UK Limited | Real estate | 2020 |
| Aura Recruitment Services Ltd | Administrative & support | 2018 |
| Aura Skin LAB Ltd | Other services | 2026 |
| Aura Trading Group Limited | Wholesale & retail | 2026 |
| Aura UP CIC | Education | 2023 |
| Aura Veritas Ltd | Wholesale & retail | 2025 |
| Aurabelle Ltd | Wholesale & retail | 2026 |
| Aurac Sound & Vision Ltd | Wholesale & retail | 2011 |
| Auracle Management Group Limited | Real estate | 2016 |
| Auradent Ltd | Health & social care | 2025 |
| Auraigent Limited | Information & communication | 2025 |
| Auraio Ltd | Wholesale & retail | 2026 |
| Auralux Ltd | Wholesale & retail | 2025 |
| Aurangzaib Khawaja Ltd | Professional & scientific | 2019 |
| Aurasafe Solutions Ltd | Professional & scientific | 2024 |
| Auravyx Limited | Wholesale & retail | 2025 |
| Aurea Jewellery Ltd | Wholesale & retail | 2025 |