| Ahillen Designs Limited | Information & communication | 2017 |
| Ahlcc Limited | Information & communication | 2020 |
| AI Printers Ltd | Administrative & support | 2019 |
| AI Race Summaries Ltd | Information & communication | 2023 |
| Aida Solutions Limited | Professional & scientific | 2003 |
| AIM Commercial Management Limited | Professional & scientific | 2025 |
| AIP Surrey Services Ltd | Administrative & support | 2025 |
| Air Conditioning Hire Limited | Financial services | 2013 |
| AJ Group Services Ltd | Financial services | 2025 |
| AJ Squared Ltd | Professional & scientific | 2021 |
| AJ Staffing Solutions Ltd | Households | 2019 |
| Aj's Studios Limited | Professional & scientific | 2009 |
| Ajadra Ltd | Wholesale & retail | 2018 |
| AJI - Builds Ltd | Construction | 2026 |
| AJP Access Services Ltd | Professional & scientific | 2021 |
| AK Technologies Solutions Ltd | Information & communication | 2025 |
| Akai Technology Co. Limited | Professional & scientific | 2019 |
| Akai Tenshi Ltd | Information & communication | 2025 |
| Akbaba Decoration Plumbing & Painting Ltd | Construction | 2020 |
| AKS Forcort Limited | Wholesale & retail | 2015 |
| Akshanani Ltd | Real estate | 2024 |
| Akss Properties Limited | Real estate | 2025 |
| AKZ Rental Properties Ltd | Real estate | 2026 |
| AKZ Rental Property Ltd | Real estate | 2026 |
| AL Araf Limited | Hospitality | 2026 |
| AL Duca -35 Willow Limited | Hospitality | 2015 |
| AL Duca Restaurant Limited | Hospitality | 1999 |
| AL Stylist Limited | Other services | 2026 |
| Al-Janabi Ltd | Information & communication | 2022 |
| ALA 70 Ltd | Manufacturing | 2022 |
| Alabrie Consulting Limited | Professional & scientific | 2010 |
| Alamut Investments Limited | Real estate | 2014 |
| Alan Professional Carpet & Upholstery Cleaner Ltd | Administrative & support | 2025 |
| Alaya Health Ltd | Health & social care | 2025 |
| Albert Rose Residential Limited | Hospitality | 2017 |
| Albert's Mobile Valeting Ltd | Administrative & support | 2023 |
| Albion House Freehold Limited | Households | 2018 |
| Albion Road Sutton Management Limited | Real estate | 1988 |
| Albion TLW Ltd. | Real estate | 2012 |
| Albrin Capital Limited | Financial services | 2014 |
| Albrin Property Ltd | Extraterritorial | 2020 |
| Albrin Subsidiary Limited | Extraterritorial | 2014 |
| Alc.Tv Limited | Manufacturing | 2013 |
| Alchemy Value Creation & Transformation Ltd | Professional & scientific | 2018 |
| Aldebran Property Group Limited | Real estate | 2026 |
| Alder and ASH Limited | Construction | 2025 |
| Aldroubi Medical International Ltd | Manufacturing | 2021 |
| ALE Bathroom & Kitchen Limited | Construction | 2016 |
| Alertcom Limited | Professional & scientific | 2020 |
| Alessi Limited | Financial services | 2005 |
| Alex Longmore Ltd | Other services | 2023 |
| Alexander & Grace Ltd | Wholesale & retail | 2020 |
| Alexander Lloyd Ltd. | Administrative & support | 1999 |
| Alexandra Conroy Ltd | Administrative & support | 2017 |
| Alexandra Mansions Freehold Limited | Real estate | 2021 |
| Alexandra Place Residents Management Company Limited | Households | 2006 |
| Alexandra Wood Ltd | Other services | 2010 |
| Alfa & Omega Plumbing and Property Services Limited | Construction | 2026 |
| Alfred DRY Cleaning Ltd | Other services | 2019 |
| Alfresco Expeditions Ltd | Education | 2024 |
| Alfresco Outdoors Ltd | Education | 2021 |
| Algar Group Limited | Financial services | 2024 |
| Algotron Limited | Information & communication | 1996 |
| Alhambra Fabrics UK Limited | Wholesale & retail | 2026 |
| Alhh Ltd | Health & social care | 2022 |
| ALI Waters Ltd | Professional & scientific | 2015 |
| ALIAS23 Ltd | Manufacturing | 2019 |
| Aligned Way Coaching Ltd | Professional & scientific | 2025 |
| Aliway Barber Ltd | Other services | 2024 |
| Alix Lawson Home Ltd | Wholesale & retail | 2020 |
| Alix Lawson London Ltd | Wholesale & retail | 2018 |
| Alix Lawson Ltd | Professional & scientific | 2018 |
| ALL About Helping Consulting Ltd | Professional & scientific | 2020 |
| ALL Round Performance Limited | Arts & recreation | 2025 |
| ALL Seasons Garden Maintenance Ltd | Administrative & support | 2016 |
| ALL Your Junk Limited | Water & waste | 2006 |
| Allectus Quantum Holdings Ltd | Financial services | 2021 |
| Allectus Quantum Ltd | Financial services | 2021 |
| Allegra Ltd | Financial services | 2022 |
| Alletak Ltd | Information & communication | 2018 |
| Alliance Coaching Limited | Professional & scientific | 2005 |
| Alliapp Limited | Other services | 2012 |
| Allied Affinity Limited | Professional & scientific | 1980 |
| Allied Security (Southern) Limited | Construction | 2012 |
| Allmanni Limited | Professional & scientific | 2025 |
| Alloy Business Innovation Ltd | Professional & scientific | 2020 |
| Alloy Partners Limited | Professional & scientific | 2026 |
| Allpoints AI Ltd | Information & communication | 2025 |
| Allprocess Control Limited | Construction | 1997 |
| Allrounder Equestrian Limited | Agriculture & fishing | 2012 |
| Alma Davina Limited | Wholesale & retail | 2023 |
| Alma Makes Limited | Administrative & support | 2024 |
| Almandene Limited | Wholesale & retail | 1988 |
| Almatec Ltd | Information & communication | 2022 |
| Alnura Ltd | Wholesale & retail | 2024 |
| Aloa Consultancy Limited | Professional & scientific | 2021 |
| Alor Construction Ltd | Construction | 2015 |
| Alpha Storage Solutions Ltd | Transport & logistics | 2023 |
| Alphaplus Investments Ltd | Financial services | 2022 |
| Alphatoons Media Group Ltd | Information & communication | 2023 |