| Algomintix Ltd | Information & communication | 2026 |
| Algorix Software Engineering Ltd | Information & communication | 2024 |
| Align and Mind Limited | Public administration | 2025 |
| Aligned Therapy Solutions Ltd | Health & social care | 2025 |
| Alimil Ltd | Financial services | 2022 |
| Alin Tiling Ltd | Construction | 2021 |
| Alistair Black Limited | Wholesale & retail | 1979 |
| Alivan Ltd | Hospitality | 2025 |
| Alka Meekhil Patel Mortgages Ltd | Financial services | 2023 |
| Alkaz Properties Limited | Hospitality | 2019 |
| Alkemal (UK) Distribution Limited | Wholesale & retail | 2020 |
| ALL About Roofing Services Limited | Construction | 2020 |
| ALL About U Care Services Limited | Health & social care | 2011 |
| ALL Area Services Limited | Wholesale & retail | 1999 |
| ALL Dolled UP Essex Ltd. | Arts & recreation | 2017 |
| ALL Green Power UK Ltd | Construction | 2019 |
| ALL Hours Medical Recruitment Ltd | Administrative & support | 2025 |
| ALL Kinds of Plant Ltd | Manufacturing | 2019 |
| ALL Pets Travel Ltd | Other services | 2025 |
| ALL Points West Ltd | Professional & scientific | 2021 |
| ALL Properties Essex Ltd | Real estate | 2024 |
| ALL Property Care Ltd | Administrative & support | 2005 |
| ALL Routes Scaffolding Ltd | Construction | 2019 |
| ALL Seasons Discount Limited | Wholesale & retail | 2020 |
| ALL Seasons Solutions Limited | Construction | 2017 |
| ALL Smiles Laboratory Ltd | Health & social care | 2019 |
| ALL Spec Interiors Limited | Construction | 2004 |
| ALL Tech 45 Limited | Wholesale & retail | 2018 |
| ALL Tech Competitions Ltd | Wholesale & retail | 2023 |
| ALL Things Alpaca Ltd | Arts & recreation | 2021 |
| ALL Things Economic Abuse Limited | Professional & scientific | 2024 |
| ALL Weather Roofing Services Ltd | Construction | 2024 |
| Alldoctors Plus Ltd | Administrative & support | 2024 |
| Allebasi Limited | Real estate | 2025 |
| Allergy Nurture Care Ltd | Health & social care | 2025 |
| Allesverloren Limited | Professional & scientific | 2020 |
| Allfresh Washroom Services Limited | Administrative & support | 2012 |
| Alliance Facade Services Limited | Construction | 2017 |
| Alliance Group UK Holdings Limited | Financial services | 2020 |
| Alliance Physiotherapy Ltd | Other services | 2009 |
| Alliance Real Estate Holdings Limited | Real estate | 2019 |
| Alliance Renewables Limited | Construction | 2025 |
| Allied Telecoms Limited | Information & communication | 2010 |
| Allieduk Ltd | Administrative & support | 2026 |
| Alloy Fabweld Limited | Manufacturing | 1996 |
| Allrollover Limited | Information & communication | 2011 |
| Allstar Coaching Academy Ltd | Education | 2019 |
| Allstar Films Ltd | Information & communication | 2025 |
| Alltech Roofing Limited | Construction | 2010 |
| Allthingscx Ltd | Information & communication | 2017 |
| Alltile Installations Ltd | Construction | 2016 |
| Allure Body Clinic Ltd | Other services | 2021 |
| Allure Greens Holdings Ltd | Extraterritorial | 2017 |
| Allure Greens Limited | Real estate | 2016 |
| Allwag Promotions Limited | Administrative & support | 1998 |
| Ally Ford Ltd | Hospitality | 2025 |
| Allyn International Services (UK) Limited | Professional & scientific | 2005 |
| Alma Drive (2021) Ltd | Real estate | 2021 |
| Alma Drive Leaseholders Limited | Households | 2003 |
| Almag Components Ltd | Professional & scientific | 2003 |
| Almas Market Ltd | Wholesale & retail | 2025 |
| Alpaca Antenna Limited | Professional & scientific | 2025 |
| Alpenspitz Handel UK Limited | Wholesale & retail | 2022 |
| Alpha Medical Care Limited | Health & social care | 2004 |
| Alpha Omega Trust Limited | Professional & scientific | 2004 |
| Alpha Piling Limited | Other services | 2019 |
| Alpha Pro Wealth Ltd | Financial services | 2022 |
| Alpha Proxima Ltd | Real estate | 2021 |
| Alphatek Marketing Solutions Ltd | Professional & scientific | 2016 |
| Alphatree Homes Limited | Health & social care | 2023 |
| Alphatree Property Limited | Real estate | 2023 |
| Alphine Care Services Limited | Administrative & support | 2016 |
| Alpine Planning Ltd | Other services | 2016 |
| Alpine Trees and Landscapes Ltd | Administrative & support | 2025 |
| Also Known AS Homes Ltd | Real estate | 2026 |
| Alsoy Take Away Ltd | Hospitality | 2025 |
| Alston Holdco Ltd | Professional & scientific | 2024 |
| ALT Enter Limited | Information & communication | 2017 |
| Altair Aviation Limited | Arts & recreation | 2003 |
| Altech Trading Company Limited | Water & waste | 1993 |
| Alternative Resource Capital LLP | | 2018 |
| Alternative USE (Marketing) Limited | Other services | 2002 |
| Altis Management Services Limited | Administrative & support | 2008 |
| Altitude Aviation Limited | Financial services | 2008 |
| Altitude Engineering Limited | Manufacturing | 2020 |
| Altitude Global Limited | Professional & scientific | 1999 |
| Altitude Internet Digital UK Ltd | Professional & scientific | 2020 |
| Alto Property Acquisitions Ltd | Real estate | 2023 |
| Alto QS Limited | Financial services | 2016 |
| Altramart Limited | Arts & recreation | 2016 |
| Aluisa Hair Chelmsford Ltd | Other services | 2023 |
| Alvaretail Ltd | Wholesale & retail | 2020 |
| Alveira Ltd | Professional & scientific | 2019 |
| Alvergate Limited | Professional & scientific | 2024 |
| Alyn Solutions Development Ltd | Information & communication | 2025 |
| Alzaib Worldwide Ltd | Wholesale & retail | 2025 |
| AM & SJ Ransome Ltd | Real estate | 2021 |
| AM Control Services Limited | Construction | 2021 |
| AM Lavender Consulting Limited | Professional & scientific | 2012 |
| AM Payroll Services Ltd | Professional & scientific | 2023 |