| ALL 4 1 Travel Ipswich Limited | Transport & logistics | 2019 |
| ALL 4 One Travel Limited | Transport & logistics | 2019 |
| ALL About Hearing Ltd | Health & social care | 2022 |
| ALL About Users Limited | Information & communication | 2018 |
| ALL Events and More Ltd | Professional & scientific | 2024 |
| ALL FIX Carpentry Ltd | Construction | 2015 |
| ALL in One Finance & Property Ltd | Financial services | 2025 |
| ALL Seasons Marquees Limited | Arts & recreation | 2012 |
| ALL Star Safety Ltd | Construction | 2019 |
| ALL Star Training Limited | Education | 2014 |
| ALL Travel Services Limited | Transport & logistics | 2019 |
| ALL Waste Solutions Limited | Water & waste | 2003 |
| All-Ears.Info Ltd | Health & social care | 2024 |
| ALL2HEALTHCARE Ltd | Health & social care | 2019 |
| Alla Svago Limited | Wholesale & retail | 2025 |
| Allbon Holdings Ltd | Financial services | 2025 |
| Allbon Homes Ltd | Construction | 2022 |
| Allbon Lettings Ltd | Real estate | 2025 |
| Allbuild Suffolk Ltd | Construction | 2024 |
| Allclear Logistics Limited | Transport & logistics | 2013 |
| Allecto Limited | Professional & scientific | 2013 |
| Allegro Creative Agency LLP | | 2020 |
| Allen House Dental Ipswich Ltd | Health & social care | 2026 |
| Allen Medical Limited | Health & social care | 2016 |
| Allen Properties Consultancy Limited Liability Partnership | | 2017 |
| Allen Stanley Ltd | Other services | 2008 |
| Allens Transport Limited | Transport & logistics | 2001 |
| Allfix (UK) Limited | Wholesale & retail | 2004 |
| Allgroom Motorsport Ltd | Arts & recreation | 2025 |
| Alliance CS Outsourcing Ltd | Wholesale & retail | 2022 |
| Allied Supplies Ltd | Wholesale & retail | 2020 |
| Allies Design Limited | Wholesale & retail | 2005 |
| Allin Deliveries Limited | Transport & logistics | 2020 |
| Alloyman Wheel Refurbishment Ltd | Wholesale & retail | 2021 |
| Allstar Training (Essex) Limited | Education | 2026 |
| Alltest UK Limited | Wholesale & retail | 2025 |
| Allula Creative Ltd | Wholesale & retail | 2024 |
| Allum Carpentry Ltd. | Construction | 2004 |
| Allway Healthcare Limited | Health & social care | 2023 |
| Almajoch Properties Limited | Real estate | 1989 |
| Almar Group Ltd | Construction | 2025 |
| Almead Limited | Administrative & support | 2003 |
| Almira Catering Ltd | Extraterritorial | 2024 |
| Almners Ltd | Professional & scientific | 2020 |
| Almond Art Limited | Wholesale & retail | 2013 |
| Almost Life Size Limited | Other services | 2016 |
| Almrep Limited | Professional & scientific | 2025 |
| Alnaty Holdings Ltd | Professional & scientific | 2018 |
| Aloe Care Ltd | Health & social care | 2022 |
| Aloe Holdings Ltd | Real estate | 2022 |
| ALP Racing Limited | Arts & recreation | 2018 |
| Alpha Contract Solutions Group Ltd | Construction | 2026 |
| Alpha Dog Supplies Ltd | Wholesale & retail | 2025 |
| Alpha Guardians Limited | Hospitality | 2013 |
| Alpha Medical (Group) Limited | Administrative & support | 2009 |
| Alpha Multi Utilities Ltd | Construction | 2018 |
| Alpha Physiotherapy Services Limited | Health & social care | 2019 |
| Alpha Rural Services Limited | Other services | 2015 |
| Alpha Security Services Limited | Administrative & support | 2019 |
| Alpha Support Haven Ltd | Health & social care | 2025 |
| Alpha-Omega Financial Services Limited | Financial services | 2007 |
| ALPHA24 Ltd | Real estate | 2025 |
| Alphagate AI Limited | Information & communication | 2026 |
| Alphagate Asset Management Ltd | Real estate | 2026 |
| Alphagate Investment Group Ltd | Other services | 2023 |
| Alphak Services Ltd | Professional & scientific | 2014 |
| Alphatech Resources Limited | Administrative & support | 2019 |
| Alrhg Limited | Real estate | 2021 |
| Alsivija Ltd | Transport & logistics | 2022 |
| ALT House Consulting Limited | Professional & scientific | 2025 |
| Alterium Limited | Financial services | 2013 |
| Alternative Services (Properties) Ltd | Households | 2023 |
| ALTI-2 Europe Limited | Manufacturing | 2009 |
| Alto East Anglia Limited | Administrative & support | 2023 |
| Alton Broadband Limited | Information & communication | 2011 |
| Alton Fivestar Limited | Construction | 2013 |
| Alton Plumbing Ltd | Construction | 2006 |
| Alton Reach (Stutton) Management Company Limited | Households | 2021 |
| Altonspire (East Anglia) Limited | Real estate | 2000 |
| Altworth Ltd. | Wholesale & retail | 2026 |
| Alusiek Ltd | Real estate | 2024 |
| Always B Extensions Limited | Other services | 2026 |
| Always B Hair Limited | Other services | 2022 |
| Alwaysconnected Consulting Ltd | Information & communication | 2018 |
| Alyarmouk Limited | Health & social care | 2014 |
| Alyosr Ltd | Wholesale & retail | 2024 |
| AM Commodities Ltd | Administrative & support | 2023 |
| AM Futures Ltd | Wholesale & retail | 2024 |
| AM Rentals Ltd | Real estate | 2024 |
| Am-Pro Coaching Ltd | Education | 2022 |
| AM2026 Ltd | Construction | 2026 |
| AMA Invest Ltd | Financial services | 2000 |
| AMA Residence Limited | Real estate | 2022 |
| AMA UK Properties Ltd | Real estate | 2021 |
| Amadeus London Limited | Real estate | 2016 |
| Amajova Ltd | Administrative & support | 2021 |
| Amal Supported Housing Ltd | Real estate | 2019 |
| Amania Trading Ltd | Manufacturing | 2006 |
| Amaris Consultancy Ltd | Information & communication | 2025 |
| Amazi Consulting Limited | Professional & scientific | 2010 |