| Alice Townes the Salon Ltd | Other services | 2023 |
| Aligned Wealth Financial Planning Ltd | Financial services | 2025 |
| Alistair Fleming Woodworks Limited | Manufacturing | 2006 |
| Alixx Media Ltd | Information & communication | 2026 |
| ALL Angles Roofing Ltd | Construction | 2014 |
| ALL Clear (Sussex) Limited | Transport & logistics | 2007 |
| ALL Iconic Brands Ltd | Information & communication | 2021 |
| ALL in the Wrap Limited | Professional & scientific | 2022 |
| ALL Logged Limited | Information & communication | 2025 |
| Allen House Management Limited | Households | 2013 |
| Allen Moss Ltd. | Professional & scientific | 2017 |
| Alleneagle Limited | Professional & scientific | 2007 |
| Allez Alps Limited | Administrative & support | 2001 |
| Alliance Trading & Investments Limited | Wholesale & retail | 2020 |
| Allumtek Business Advisors Ltd | Professional & scientific | 2024 |
| Allure Calcio Limited | Manufacturing | 2021 |
| Alpha Family Holdings Limited | Financial services | 2024 |
| Alpha Family Investments Ltd | Financial services | 2022 |
| Alpha Sussex Private Hire Ltd | Transport & logistics | 2022 |
| Alpha Ventures Investment LLP | | 2020 |
| Alphacraft Limited | Information & communication | 2020 |
| ALR Commercial Ltd | Real estate | 2020 |
| ALR Projects Ltd | Administrative & support | 2019 |
| Alstrom Real Estate Ltd | Real estate | 2026 |
| ALT Ventures Limited | Administrative & support | 2024 |
| Altech Engineering Limited | Manufacturing | 1997 |
| Altimeter UK Ltd | Information & communication | 2010 |
| Aluka Home Ltd | Manufacturing | 2022 |
| Alun Gedrych Ltd | Construction | 2005 |
| Alunora Limited | Wholesale & retail | 2025 |
| Always Enterprises Ltd | Wholesale & retail | 2025 |
| AM Smart Energy Limited | Other services | 2009 |
| Amasya Limited | Arts & recreation | 2012 |
| Amber Foster Consulting Ltd | Administrative & support | 2014 |
| Ambrose Design Services Limited | Professional & scientific | 1997 |
| Amcr Capital Ltd | Professional & scientific | 2022 |
| American Exports Ltd | Wholesale & retail | 2026 |
| Ameski UK Ltd | Transport & logistics | 2025 |
| Amet Contracting Group Ltd | Construction | 2020 |
| Amet Groundworks Ltd | Construction | 2020 |
| Amet Landscapes Ltd | Administrative & support | 2020 |
| AMF Lets Ltd | Real estate | 2025 |
| Amici Sanitize Limited | Administrative & support | 2005 |
| Amie Conte Beauty Limited | Other services | 2008 |
| Amigo Partnership (UK) Ltd | Professional & scientific | 2014 |
| Amira's Kitchen Limited | Hospitality | 2017 |
| Amira's Lounge Ltd | Hospitality | 2020 |
| Ammg Consultancy Limited | Professional & scientific | 2024 |
| Amnis Developments Ltd | Construction | 2022 |
| AMP Strategies Limited | Professional & scientific | 2014 |
| AMS Golf Ltd | Administrative & support | 2017 |
| Amulligan 365 Ltd | Information & communication | 2022 |
| AMV Worldwide Limited | Administrative & support | 2007 |
| AMY Fell Ltd | Professional & scientific | 2024 |
| AMY Food & Wine Ltd | Wholesale & retail | 2023 |
| AMY Packer Academy Limited | Administrative & support | 2024 |
| AN Invisible Republic Ltd | Manufacturing | 2007 |
| Anchor Hartfield Limited | Hospitality | 2018 |
| Ancient Wood Trust | Health & social care | 2013 |
| Anderson Financial Limited | Professional & scientific | 2003 |
| Anderson Talent Limited | Administrative & support | 2025 |
| Andrea Barnes Limited | Administrative & support | 2024 |
| Andreas Construction Ltd | Construction | 2016 |
| Andrew Paine Architecture Limited | Professional & scientific | 2011 |
| Andrew Turner Engineering Ltd | Professional & scientific | 2022 |
| Andrews Print International Limited | Manufacturing | 2016 |
| Andromeda MGT Limited | Real estate | 2020 |
| Andy Burrell Architecture Limited | Professional & scientific | 2023 |
| Andy Bushby Electrical Ltd | Construction | 2023 |
| Andy Carlisle Ltd | Professional & scientific | 2024 |
| Andy's Cars Limited | Wholesale & retail | 2021 |
| Anemoi Group Ltd | Financial services | 2020 |
| Anemoi Ventures Limited | Other services | 2022 |
| Angel Services 78 Ltd | Construction | 2023 |
| Angels' Beauty Ltd | Other services | 2018 |
| Angola Beverages Holding Company Limited | Manufacturing | 2017 |
| Angus Fraser Marketing Ltd | Professional & scientific | 2010 |
| Animate Wisdom Ltd | Professional & scientific | 2026 |
| Anna DE Filippo Ltd | Other services | 2012 |
| Annahitah Ltd | Wholesale & retail | 2023 |
| Annvkeeling Consulting Limited | Professional & scientific | 2022 |
| ANO & AKS Ltd | Wholesale & retail | 2023 |
| Anomalous Materials Ltd. | Information & communication | 2021 |
| Another Footnote Ltd | Information & communication | 2020 |
| Anouradha Consulting Limited | Health & social care | 2026 |
| Ansty Hall Ltd. | Construction | 1990 |
| Anthemics Limited | Professional & scientific | 2024 |
| AO Cycling Ltd | Arts & recreation | 2022 |
| APE2O Limited | Manufacturing | 2018 |
| Apex Carries Ltd | Arts & recreation | 2023 |
| Apex Velocity Racing Ltd | Professional & scientific | 2026 |
| APG Sourced Ltd | Administrative & support | 2020 |
| Aphrite Ltd | Information & communication | 2023 |
| Apollo Bags Limited | Wholesale & retail | 2008 |
| Apostle Ltd | Professional & scientific | 2024 |
| Apple and OAT Ltd | Manufacturing | 2025 |
| Appledore Gardens Management Co. Limited | Professional & scientific | 1994 |
| Applegarth Estate Ltd | Real estate | 2018 |
| Appleyard Meat Supplies Ltd | Wholesale & retail | 2008 |
| Apricity Group Ltd | Professional & scientific | 2022 |