| ATA Services (Manchester) Limited | Wholesale & retail | 2015 |
| ATA Syrian Foods Limited | Hospitality | 2026 |
| Ataaks Ltd | Wholesale & retail | 2023 |
| Atak Kebab Limited | Hospitality | 2021 |
| Atan Ltd | Manufacturing | 2025 |
| Atarob Ltd | Education | 2025 |
| Atash Services Ltd | Administrative & support | 2020 |
| Atavistic Technologies Ltd | Information & communication | 2017 |
| ATB Foods (NW) Ltd | Hospitality | 2019 |
| ATB Media Productions Ltd | Information & communication | 2021 |
| Atbrook Estates Limited | Construction | 2016 |
| Atbsb Limited | Information & communication | 2020 |
| ATC Airfield Training Company Limited | Professional & scientific | 2024 |
| ATC Forklifts Ltd | Wholesale & retail | 2025 |
| ATC Garden Maintenance Limited | Administrative & support | 2016 |
| ATC Recruitment Limited | Administrative & support | 2009 |
| Atca Time Instrument Limited | Manufacturing | 2021 |
| ATD Eco Heating Ltd | Construction | 2025 |
| ATD Eras Limited | Extraterritorial | 2021 |
| Ateam Building and Property Management Ltd | Real estate | 2021 |
| Atec Design & Renovation Limited | Construction | 2022 |
| Ateca Global Ltd | Information & communication | 2025 |
| Ateca Global Properties Ltd | Real estate | 2026 |
| Atelier Art (Manchester) Ltd | Arts & recreation | 2011 |
| Atelier Art Limited | Administrative & support | 2011 |
| Atelier Brick & Vault Ltd | Real estate | 2026 |
| Atelier Crescendo Holding Ltd | Professional & scientific | 2024 |
| Atelier Events Limited | Hospitality | 2022 |
| Atelier Integral Limited | Professional & scientific | 2026 |
| Atelier Management Company Limited | Other services | 2021 |
| Atelier MB Ltd | Professional & scientific | 2013 |
| Atelier Print House Ltd | Manufacturing | 2026 |
| Atelier Rose & Gray Limited | Wholesale & retail | 2013 |
| Atelier Shift Ltd | Professional & scientific | 2025 |
| Atelier Whimsy Ltd | Education | 2026 |
| Atelierseventeen Ltd | Wholesale & retail | 2026 |
| Atemi Sports Limited | Wholesale & retail | 2017 |
| Atenshi for Trading Ltd | Wholesale & retail | 2026 |
| Ateres Bunois Seminary Ltd | Education | 2014 |
| Ateres Elisheva | Education | 2017 |
| ATF Builders Ltd | Construction | 2024 |
| Atfme Ltd | Hospitality | 2025 |
| Atfoll Ltd. | Real estate | 2018 |
| ATG Properties Ltd | Real estate | 2023 |
| ATG Property Group Ltd | Real estate | 2023 |
| ATH Textile Limited | Wholesale & retail | 2020 |
| Athar Home Store Limited | Wholesale & retail | 2026 |
| Athb Technologies Ltd | Construction | 2021 |
| Athena Consultancy Group Ltd | Professional & scientific | 2022 |
| Athena Costs Ltd | Professional & scientific | 2024 |
| Athena EOS Partners Limited | Administrative & support | 2023 |
| Athena Management Solutions Limited | Professional & scientific | 2025 |
| Athena Optical Ltd | Health & social care | 2017 |
| Athena Solicitors LLP | | 2013 |
| Athena Trustees Ltd | Professional & scientific | 2023 |
| Athenion Holdings Limited | Financial services | 2025 |
| Athens Food Trade Ltd | Wholesale & retail | 2018 |
| Ather Trading Ltd | Construction | 2025 |
| Atherden Fuller Leng (Holdings) Limited | Financial services | 2022 |
| Atherden Fuller Leng Limited | Professional & scientific | 1997 |
| Atherstone Mews Property Limited | Real estate | 2022 |
| Atherton Appliance Outlet Ltd | Wholesale & retail | 2016 |
| Atherton Auto Parts Ltd | Wholesale & retail | 2010 |
| Atherton Boiler & Central Heating Services Limited | Construction | 2009 |
| Atherton Car Company Ltd | Wholesale & retail | 2011 |
| Atherton Catering Ltd | Hospitality | 2026 |
| Atherton Clarke LLP | | 2010 |
| Atherton Collieries FC C.I.C. | Arts & recreation | 2010 |
| Atherton Community Trust Limited | Other services | 2011 |
| Atherton Creative Engineering Limited | Professional & scientific | 2015 |
| Atherton Cricket Club Limited | Arts & recreation | 2019 |
| Atherton Digital Marketing Ltd | Wholesale & retail | 2023 |
| Atherton Drain Services Ltd | Other services | 2020 |
| Atherton Drivers Service Ltd | Transport & logistics | 2022 |
| Atherton Financial Consultancy Limited | Financial services | 2013 |
| Atherton L.R.A.F.C. Limited | Arts & recreation | 1989 |
| Atherton Laburnum Rovers Juniors CIC | Arts & recreation | 2025 |
| Atherton Physiotherapy and Sports Injury Clinic Limited | Health & social care | 2019 |
| Atherton Pre-School Day Care Limited | Education | 2006 |
| Atherton Roofing & Construction Ltd | Construction | 2025 |
| Atherton Tech Ltd | Wholesale & retail | 2021 |
| Atherton Vehicle Services Ltd | Wholesale & retail | 2023 |
| Atherton Waring LLP | | 2009 |
| Athlete Business School Ltd | Information & communication | 2020 |
| Athlete Matters Limited | Health & social care | 2008 |
| Athlete Welfare Initiative Ltd | Education | 2020 |
| Athlete X Ltd | Professional & scientific | 2026 |
| Athletic Group UK Ltd | Wholesale & retail | 2015 |
| Athletic Minds Academy Ltd | Professional & scientific | 2023 |
| Athleton Ltd | Wholesale & retail | 2025 |
| Athmar Union Limited | Administrative & support | 2015 |
| Athonet UK Limited | Information & communication | 2017 |
| Athos Physio Limited | Health & social care | 2020 |
| Athreeash Limited | Wholesale & retail | 2025 |
| Athru Psychotherapy Ltd | Other services | 2018 |
| ATI Maintenance Ltd | Construction | 2023 |
| ATI Optix Ltd | Other services | 2014 |
| Ati-Industrie Ltd | Manufacturing | 2013 |
| Atid Ltd | Professional & scientific | 2008 |
| Atif & Partners Ltd | Information & communication | 2024 |