| Atevolve Limited | Enfield | 2024 |
| ATF Funeral Committee Ltd | Stoke-On-Trent | 2023 |
| ATF Trust and Estate Planning Ltd | Weston Super Mare | 2012 |
| Atfitnessuk Ltd | Greenford | 2021 |
| ATG Collection Services Ltd | Keston | 2023 |
| ATG Domestic Repairs Ltd | Chelmsford | 2026 |
| ATG Hair Ltd | London | 2020 |
| ATG Luxuries Limited | Maidenhead | 2024 |
| ATG Luxx Ltd | Maidenhead | 2026 |
| ATG Property Developments Limited | Cannock | 2012 |
| Atglobe Research Limited | London | 2010 |
| ATH an Chuillean Services Ltd | Richmond | 2021 |
| ATH Corporate Ltd | Newport | 2025 |
| ATH Fish Services Ltd | Shetland | 2021 |
| ATH Inc Ltd | London | 2019 |
| ATH Studios London Ltd | London | 2026 |
| Atha Developments (NO. 1) Limited | Middlesbrough | 2013 |
| Atha Developments (NO. 2) Limited | Middlesbrough | 2017 |
| Atha Developments (NO. 3) Limited | Middlesbrough | 2018 |
| Atha Developments (NO. 4) Limited | Middlesbrough | 2024 |
| Atha Yoga Limited | London | 2025 |
| Athaliah's Artistry Limited | Smethwick | 2024 |
| Athan A&V Ltd | Bolton | 2024 |
| Atharier Ltd | Ashford | 2025 |
| Atheian Limited | London | 2020 |
| Atheism UK | London | 2009 |
| Athelas CIC | Pudsey | 2016 |
| Atheli-Care Ltd | Halifax | 2026 |
| Athelney Limited | Wells | 2022 |
| Athena (Beauty and Nails) Ltd | Dorchester | 2013 |
| Athena Aesthetics & Wellbeing Clinic Ltd | Dartford | 2025 |
| Athena Aesthetics and Beauty Limited | Redditch | 2018 |
| Athena Appointments Limited | Aberdeen | 2024 |
| Athena Beauty Academy Ltd | Redditch | 2019 |
| Athena Circus Academy Ltd | Gravesend | 2022 |
| Athena Commerce Limited | Poole | 2019 |
| Athena Connection Limited | Watford | 2006 |
| Athena Cosmetix Limited | Beckenham | 2022 |
| Athena Dhir Trading Ltd | Leeds | 2018 |
| Athena Engineering Limited | Preston | 2008 |
| Athena Engineering Services Ltd | Cardiff | 2015 |
| Athena Hair Ltd | Plymouth | 2019 |
| Athena Logistics Limited | Birmingham | 2025 |
| Athena Mechanical Services Limited | Colchester | 2014 |
| Athena Medical PR Limited | London | 1997 |
| Athena Nails Studio Limited | Chelmsford | 2025 |
| Athena Rising Consulting & Mentoring Ltd | London | 2020 |
| Athena Salons Ltd | London | 2021 |
| Athena Studio Ltd | Stamford | 2020 |
| Athena Tanning Hair & Beauty Salon Ltd | Shipley | 2005 |
| Athenae Ltd | Essex | 2006 |
| Athene Hair & Beauty Ltd | Staffs | 2007 |
| Athene Leadership Coaching Ltd | Walton-On-Thames | 2019 |
| Athenia Aesthetics Limited | Whitstable | 2024 |
| Athentinaa Ltd | London | 2024 |
| Atheria Limited | Holywood | 2025 |
| Atherley Cleaners Limited | Romsey | 1987 |
| Atherstone Natural Nail Care Limited | Atherstone | 2018 |
| Atherton Bailey Limited | Crawley | 2014 |
| Atherton Community Trust Limited | Manchester | 2011 |
| Atherton COX Limited | London | 2003 |
| Atherton Drain Services Ltd | Manchester | 2020 |
| Atherton Pugh Associates Limited | Battlesbridge | 2017 |
| Atherton Signs & Installations Limited | Ilkeston | 2017 |
| Athey's Moor Flying School Limited | Morpeth | 2021 |
| Atheys Moor Experiences Ltd | Longframlington | 2026 |
| Athey’S Moor Flying Academy Ltd | Longframlington | 2026 |
| Athghin Center for Spiritual Formation Ltd | Lisburn | 2026 |
| Athh Limited | Newcast | 2026 |
| Athlete Career Transition (ACT) Ltd | Southampton | 2011 |
| Athlete Recovery Zone Ltd | Dundee | 2024 |
| Athlete Training Systems Ltd | Bo'Ness | 2015 |
| ATHLETE1ST Limited | Alderley Edge | 2018 |
| Athletic Development Club Online Ltd | London | 2019 |
| Athletic Fitness & Nutrition Ltd | Tredegar | 2014 |
| Athletic Midlands Academy CIC | Birmingham | 2022 |
| Athletic Performance Plus Limited | Stanstead Abbotts | 2009 |
| Athletic Revolution Ltd | Kenilworth | 2025 |
| Athletic Shoulder Ltd | London | 2018 |
| Athletic Skills Limited | York | 2024 |
| Athlety Ltd | London | 2024 |
| Athlos Fitness Ltd | Edinburgh | 2025 |
| Atholl and Breadalbane Agricultural Society | Aberfeldy | 2015 |
| Atholl Homes (Scotland) Ltd. | Motherwell | 2012 |
| Atholl Operative's Limited | Elgin | 2021 |
| Atholldawn Limited | Edinburgh | 2000 |
| Athora Aesthetics Limited | Oldham | 2026 |
| Athos London Ltd | Enfield | 2026 |
| Athru Psychotherapy Ltd | Manchester | 2018 |
| Atht Limited | London | 2010 |
| ATI Green Energy Ltd | Cleckheaton | 2016 |
| ATI Optix Ltd | Manchester | 2014 |
| ATI Property Holdings Ltd | Cleckheaton | 2016 |
| ATI2UDE Ltd | Kidwelly | 2022 |
| ATIBHAI.1 Limited | Cardiff | 2018 |
| Aticos Hair Studio Limited | Leigh | 1996 |
| Atif & Sons Ltd | Aldershot | 2017 |
| Atifparts Ltd | East Kilbride | 2019 |
| Atika Limited | Warrington | 2018 |
| Atil Solutions Ltd | London | 2016 |