| Article 27 Ltd | Administrative & support | 2020 |
| Artico Enabling Services Limited | Professional & scientific | 2019 |
| Articulate Life Ltd | Professional & scientific | 2020 |
| Artificial Floral Supplies Limited | Wholesale & retail | 2012 |
| Artificial Intelligence Media and Technology Ltd | Professional & scientific | 2020 |
| Artim Holding PC | | 2017 |
| Artimis Communications Limited | Information & communication | 2011 |
| Artin Crown Productions Limited | Information & communication | 2025 |
| Artinvest State Ltd | Administrative & support | 2019 |
| Artisan Aura Boutique Limited | Wholesale & retail | 2025 |
| Artisan Brewing Company Ltd | Manufacturing | 2008 |
| Artisan Group Holdings Ltd | Administrative & support | 2020 |
| Artisan Project Solutions Limited | Professional & scientific | 2014 |
| Artisan Wine Storage Ltd | Wholesale & retail | 2014 |
| Artisan's Alley Limited | Professional & scientific | 2013 |
| Artistic Krowns Ltd | Other services | 2021 |
| Artistic Monkeys Limited | Other services | 2012 |
| Artistique Group Ltd | Wholesale & retail | 2021 |
| Artistry in Motion Ltd | Wholesale & retail | 2025 |
| Artizy Services Limited | Administrative & support | 2023 |
| Artlemagne Ltd | Information & communication | 2025 |
| Artly Limited | Wholesale & retail | 2026 |
| Artmixx Ltd | Wholesale & retail | 2024 |
| Artmoli Limited | Manufacturing | 2021 |
| Artmusic & Artschool International Ltd | Information & communication | 2025 |
| Artoby Limited | Hospitality | 2018 |
| Artoshi Ltd | Information & communication | 2021 |
| Artree Beauty Ltd | Wholesale & retail | 2021 |
| Arts & Business Cymru | Arts & recreation | 2011 |
| Arts & Business Cymru Trading Limited | Arts & recreation | 2011 |
| Arts Active Trust | Arts & recreation | 1989 |
| Arts Arkade Limited | Arts & recreation | 2023 |
| Arts Cafe Painswick Ltd | Hospitality | 2023 |
| Artsn Limited | Wholesale & retail | 2023 |
| Artspacecardiff Ltd | Education | 2025 |
| Artstation | Arts & recreation | 1996 |
| Artum Energy Ltd | Transport & logistics | 2012 |
| Artvesto Ltd | Information & communication | 2018 |
| Artviayou Ltd | Wholesale & retail | 2019 |
| Artwell-Uk Ltd | Households | 2018 |
| Artytechs Consulting Ltd | Professional & scientific | 2018 |
| Arunam Enterprise Ltd | Information & communication | 2024 |
| Arundell Marine Solutions Limited | Manufacturing | 2014 |
| Arunvill Global Equity Trading Limited | Financial services | 2012 |
| Arvest Group Ltd | Information & communication | 2025 |
| Arvita Ltd | Information & communication | 2025 |
| Arways Travel Ltd. | Transport & logistics | 2022 |
| Arwen Aerospace Limited | Professional & scientific | 2021 |
| Arwo Optics Ltd | Health & social care | 2023 |
| Arxel Trade Limited | Wholesale & retail | 2025 |
| Arxel Trading Limited | Wholesale & retail | 2025 |
| ARY Logistics Ltd | Transport & logistics | 2022 |
| Arya Labs Ltd | Information & communication | 2024 |
| Aryan Cardiff Ltd | Hospitality | 2024 |
| Aryan Pharma Limited | Wholesale & retail | 2022 |
| Aryana Properties Limited | Extraterritorial | 2012 |
| Aryash Home Cosmetics Company Ltd | Wholesale & retail | 2025 |
| AS & GS Property Ltd | Real estate | 2022 |
| AS Brothers Property Ltd | Real estate | 2025 |
| AS Careworkers Limited | Administrative & support | 2019 |
| AS Electrical Solutions Ltd | Construction | 2020 |
| AS Events (Newport) Limited | Other services | 2020 |
| AS Flash Construction Limited | Construction | 2020 |
| AS Fresh AS a Daisy Aesthetics Ltd | Health & social care | 2021 |
| AS Good AS Your Mind Ltd | Professional & scientific | 2018 |
| AS Passive Solutions Ltd | Administrative & support | 2025 |
| AS Squared Ltd | Professional & scientific | 2019 |
| AS Supermart Ltd | Wholesale & retail | 2025 |
| AS UK Property Ltd | Real estate | 2023 |
| AS Yorkshire Logistics & Cars Ltd | Wholesale & retail | 2024 |
| As&Kins Ltd | Wholesale & retail | 2025 |
| As&Mh Limited | Real estate | 2024 |
| AS207960 Cyfyngedig | Information & communication | 2020 |
| ASA Autos Northwest Ltd | Transport & logistics | 2019 |
| ASA Dental Ltd | Health & social care | 2023 |
| ASA Events Management & Consultancy Specialists Ltd | Administrative & support | 2017 |
| ASA Mart Ltd | Wholesale & retail | 2025 |
| ASA Residences Ltd | Real estate | 2025 |
| Asador 44 Limited | Hospitality | 2015 |
| Asahcdcre Mart Ltd | Wholesale & retail | 2025 |
| Asai Trade John Kath Ltd | Manufacturing | 2025 |
| Asaje LLP | | 2026 |
| Asap Bitz Ltd | Wholesale & retail | 2018 |
| Asap Electrical Cardiff Limited | Construction | 2026 |
| Asap Food Solutions Ltd | Other services | 2025 |
| Asap Wales Services Limited | Other services | 2022 |
| Asapp Logistics Ltd | Transport & logistics | 2025 |
| Asar Holdings Ltd | Real estate | 2026 |
| Asara Limited | Hospitality | 2014 |
| Asaysi Limited | Other services | 2019 |
| Asbestburo Ltd | Real estate | 2025 |
| Ascend Productions Ltd | Professional & scientific | 2017 |
| Ascend Strategy Consultants Ltd | Professional & scientific | 2025 |
| Ascendancy Holdings Ltd | Wholesale & retail | 2021 |
| Ascendant Cleaners Limited | Administrative & support | 2016 |
| Ascended Operations Ltd | Wholesale & retail | 2026 |
| Ascendia Solutions Limited | Wholesale & retail | 2010 |
| Ascendia Wholesalers Ltd | Wholesale & retail | 2025 |
| Ascendio Mentor Ltd | Information & communication | 2025 |
| Ascendium Health Ltd | Health & social care | 2025 |