| Allerton Builders (Leeds) Limited | Construction | 2007 |
| Allerton Consultancy Limited | Information & communication | 2020 |
| Allerton Dale & Co. Limited | Wholesale & retail | 1976 |
| Allerton Hall Flats (Maintenance) Limited | Households | 1982 |
| Allerton Hall Management Company Limited | Households | 2004 |
| Allerton Yorkshire Holdings Limited | Financial services | 2022 |
| Allertons Coffee Limited | Hospitality | 2024 |
| Allertons Holdings Limited | Financial services | 2026 |
| Allertons Stores Limited | Wholesale & retail | 2018 |
| Allertons Trading Limited | Wholesale & retail | 2026 |
| Alleviate Property Solutions Ltd | Real estate | 2019 |
| Allfab Electrical & Mechanical Services Ltd | Manufacturing | 2012 |
| Allfleet Limited | Wholesale & retail | 2026 |
| Alliance Boxing Academy CIC | Arts & recreation | 2025 |
| Alliance Consultancy (UK) Ltd | Professional & scientific | 2018 |
| Alliance Development Group Limited | Administrative & support | 2016 |
| Alliance DM Ltd | Professional & scientific | 2019 |
| Alliance Environment and Planning Limited | Professional & scientific | 1998 |
| Alliance Flooring Limited | Construction | 2011 |
| Alliance Law Solicitors Limited | Professional & scientific | 2010 |
| Alliance of Medical Experts Limited | Health & social care | 2013 |
| Alliance Services Associates Ltd | Real estate | 2023 |
| Alliance Sync Ltd | Real estate | 2024 |
| Alliance Workforce Limited | Administrative & support | 2002 |
| Allied Global Traders Limited | Wholesale & retail | 2021 |
| Allied Machinery Limited | Manufacturing | 1992 |
| Allied Mayfair Properties Limited | Households | 2016 |
| Allied Surveyors York Limited | Professional & scientific | 2023 |
| Allientouch Ltd | Hospitality | 2025 |
| Allingham Sports Medicine Limited | Health & social care | 2023 |
| Alliren Company Ltd | Health & social care | 2021 |
| Allisa Limited | Hospitality | 2023 |
| Allistor Bennett Solicitors Ltd | Professional & scientific | 2025 |
| Alljem Ltd | Information & communication | 2022 |
| Allmore Building Maintenance Limited | Administrative & support | 2023 |
| Allo Technology Limited | Manufacturing | 2025 |
| Alloi Herbs Limited | Agriculture & fishing | 2012 |
| Allot Healthcare Ltd | Health & social care | 2023 |
| Allowed Hope Ltd | Health & social care | 2022 |
| Allsop Letting and Management Limited | Real estate | 1999 |
| Allsop Support Services Limited | Professional & scientific | 2009 |
| Allsorts Fireworks Limited | Arts & recreation | 2017 |
| Allspace Furnishings Ltd | Manufacturing | 2024 |
| Allstar Group Limited | Financial services | 2021 |
| Allstar Media Services Limited | Information & communication | 2016 |
| Allstar Psychics Limited | Information & communication | 2013 |
| Allsteel Projects Limited | Manufacturing | 2018 |
| Allthingsunlimited Ltd | Professional & scientific | 2024 |
| Alltogether Design Ltd | Professional & scientific | 2024 |
| Alltrades Bespoke Builders Ltd | Construction | 2019 |
| Alltroh Ltd | Other services | 2016 |
| Alltrux Mixers Ltd | Manufacturing | 2007 |
| Alluceo Partners Ltd | Professional & scientific | 2020 |
| Allure Abode Ltd | Real estate | 2025 |
| Allure Skin Medical Aesthetics Ltd | Health & social care | 2022 |
| Allure Weightloss Limited | Health & social care | 2020 |
| Allurebyaaa Ltd | Wholesale & retail | 2026 |
| Allwood Joinery and Building Services Limited | Construction | 2023 |
| Allworldskiing Limited | Administrative & support | 2025 |
| ALM Car and Commercial Limited | Wholesale & retail | 2012 |
| ALM21 Properties Ltd | Real estate | 2021 |
| Alma Keytes Limited | Real estate | 2023 |
| Alma Street Social Limited | Hospitality | 2021 |
| Almaas Trading Ltd | Wholesale & retail | 2018 |
| Almanal UK Ltd | Hospitality | 2023 |
| Almanda Carpets Limited | Wholesale & retail | 2005 |
| Almansoor Estates Ltd | Real estate | 2023 |
| Almas Management and Consulting Limited | Professional & scientific | 2018 |
| Almax Electrical Ltd | Construction | 2020 |
| Almaz Residence Ltd | Real estate | 2024 |
| Almighty Events Ltd | Administrative & support | 2022 |
| Almiraj UK Ltd | Information & communication | 2022 |
| Almond Bennett Developments Ltd | Construction | 2024 |
| Almondbury Properties Limited | Construction | 2019 |
| Alms Healthcare Services Ltd | Health & social care | 2025 |
| Almscliffe Dhesi Developments (1) Limited | Construction | 2019 |
| Almscliffe Dhesi Developments (Amble) Limited | Construction | 2025 |
| Almscliffe Dhesi Developments (Ashington) Limited | Construction | 2023 |
| Almscliffe Dhesi Developments (Crook) Limited | Construction | 2022 |
| Almscliffe Dhesi Developments (Knaresborough) Limited | Real estate | 2025 |
| Almscliffe Dhesi Developments (Louth) Limited | Construction | 2024 |
| Almscliffe Dhesi Developments (Manse Farm) Limited | Real estate | 2025 |
| Almscliffe Dhesi Developments (Peterlee) Limited | Construction | 2021 |
| Almscliffe Dhesi Developments (Stanley) Limited | Construction | 2021 |
| Almscliffe Dhesi Developments (Thirsk) Limited | Real estate | 2026 |
| Almscliffe Properties (Darlington) Ltd | Construction | 2019 |
| Almscliffe Properties Limited | Construction | 2018 |
| Alne Limited | Hospitality | 2019 |
| Alne Mews (Management Company) Limited | Households | 1998 |
| Alnojoom Trading Ltd | Manufacturing | 2023 |
| Alnuaaimat Ltd | Construction | 2021 |
| Aloe Properties Limited | Real estate | 2024 |
| Alol Limited | Wholesale & retail | 2010 |
| Alora Studios Group Ltd | Arts & recreation | 2025 |
| Alotsold Auction (UK) Ltd | Real estate | 2016 |
| Alotsold Vehicle Auctions Ltd | Professional & scientific | 2017 |
| Alpacka LLP | | 2015 |
| Alpha & Omega Liverpool Ltd | Wholesale & retail | 2024 |
| Alpha Alpha Supreme Care Ltd | Health & social care | 2013 |
| Alpha Assist Limited | Other services | 2019 |