| Ashton Gate Residents Company Limited | Households | 2013 |
| Askobar Limited | Administrative & support | 2026 |
| Aspera Operations Ltd | Financial services | 2024 |
| Aspire Care Group Ltd | Other services | 2017 |
| Assertor Ltd | Construction | 2024 |
| Asset Recovery London Ltd | Extraterritorial | 2024 |
| AST Building Contractors Ltd | Construction | 2013 |
| Asya Top Limited | Hospitality | 2018 |
| AT Cameden Ltd | Wholesale & retail | 2021 |
| Atarah Ltd | Administrative & support | 2013 |
| Atelier Nexus Ltd | Information & communication | 2025 |
| Atelier UN. Limited | Wholesale & retail | 2021 |
| Ates Catering Ltd | Hospitality | 2017 |
| Ates Investment Limited | Real estate | 2020 |
| Atestment Limited | Information & communication | 2024 |
| Athao Homebuilds & Renovations Ltd | Construction | 2021 |
| Atkins V & a Ltd | Construction | 2023 |
| ATL Logistics & Cargo Solutions Ltd | Transport & logistics | 2025 |
| Atlabs Infotech Ltd | Wholesale & retail | 2019 |
| Atlantis Accountancy & Tax Services Ltd | Professional & scientific | 2021 |
| Atlas Facilitates Services Ltd | Administrative & support | 2026 |
| Atmaca Holdings Ltd | Real estate | 2023 |
| Atom Commodities Limited | Professional & scientific | 2025 |
| Atom Management Limited | Real estate | 2024 |
| Attained by KEM Ltd | Wholesale & retail | 2023 |
| Audley Green (Great Chesterford) Management Company Limited | Households | 2025 |
| Augmented Reality Limited | Professional & scientific | 2013 |
| Aura Vent Ltd | Construction | 2014 |
| Aureus Chauffeurs Ltd | Transport & logistics | 2025 |
| Aurum Bar & Grill Ltd | Hospitality | 2025 |
| Autobatprim Ltd | Manufacturing | 2018 |
| Avenir Accountants Limited | Professional & scientific | 2016 |
| Avfd Limited | Professional & scientific | 2019 |
| AWE & Wonder Ltd | Health & social care | 2021 |
| Axeil Technology Services Ltd | Information & communication | 2011 |
| Axentra Management Ltd | Information & communication | 2026 |
| Axiomsec Ltd | Information & communication | 2024 |
| Axon Chemicals Limited | Manufacturing | 2025 |
| Aykas Private Chef & Consultancy Ltd | Hospitality | 2019 |
| Aylis Enver Ltd | Professional & scientific | 2025 |
| Aysegul Food Ltd | Hospitality | 2025 |
| Aytac 79 Scrap & Metal Collect Limited | Wholesale & retail | 2021 |
| Azad Barbering Ltd | Other services | 2020 |
| Aztec Enterprises Limited | Construction | 1998 |
| B & J Fisheries Limited | Wholesale & retail | 2009 |
| B a Higgins Limited | Administrative & support | 2016 |
| B Invogue Ltd | Wholesale & retail | 2016 |
| B S Investments (LON) Ltd | Real estate | 2017 |
| B W Productions Ltd | Information & communication | 2016 |
| B.I.R. Ltd | Hospitality | 2018 |
| B1 Ortak Ltd | Other services | 2025 |
| B2B Group Travel Ltd | Administrative & support | 2015 |
| B2BC Studio Ltd | Professional & scientific | 2012 |
| Baba Carers Ltd | Health & social care | 2025 |
| Babee Clothing Ltd | Wholesale & retail | 2019 |
| Baby Sensory (Harlow & Bishops Stortford) Ltd | Health & social care | 2016 |
| Bahattin Ltd | Hospitality | 2025 |
| Balalan Entertainment Limited | Transport & logistics | 2024 |
| Balance and Health Academy Limited | Education | 2021 |
| Balloosh Ltd | Arts & recreation | 2022 |
| Bamboo Connect Limited | Wholesale & retail | 2009 |
| Bamboo Distribution Limited | Wholesale & retail | 2024 |
| Bamboo Environmental Ltd | Wholesale & retail | 2011 |
| Banafsh Care Ltd | Public administration | 2022 |
| Bang Casting Studios Limited | Administrative & support | 2016 |
| Banu Creative Ltd | Information & communication | 2022 |
| Baran Group Limited | Hospitality | 2025 |
| Barclay Court (Hoddesdon) Freehold Company Limited | Households | 2020 |
| Barnard Road Limited | Real estate | 2025 |
| Bartlett Hammond Limited | Real estate | 2003 |
| Base Utilities & Civils Ltd | Energy | 2023 |
| Bast Analytics Limited | Professional & scientific | 2019 |
| Bast Consultancy Limited | Professional & scientific | 2021 |
| Batchsafe Ltd | Manufacturing | 2026 |
| Bath 12 Ltd | Hospitality | 2026 |
| Bayeux Mews (Tidworth) Management Company Limited | Households | 2006 |
| BBJ Lighting Limited | Professional & scientific | 2025 |
| BCS Auto Group Limited | Wholesale & retail | 2026 |
| BDK Sourcing & Supply Ltd | Wholesale & retail | 2018 |
| Be.Retreats Limited | Arts & recreation | 2024 |
| Beau Beauty by Molly Victoria Ltd | Other services | 2024 |
| Beauty Within - Waltham Abbey Limited | Other services | 2026 |
| Beauty World Cosmetics Limited | Wholesale & retail | 2020 |
| Beech Hill Groundworks & Maintenance Limited | Construction | 2015 |
| Beechhall Group Limited | Manufacturing | 2015 |
| Beenovation Ltd | Information & communication | 2019 |
| BEL Home and Co. Ltd | Other services | 2023 |
| Belinis Consulting Ltd | Information & communication | 2026 |
| Bell & Buckley Taverns (UK) Limited | Wholesale & retail | 2006 |
| Belle Bunii Limited | Wholesale & retail | 2021 |
| Bells Pubs Limited | Hospitality | 2019 |
| Belmavia Ltd | Wholesale & retail | 2026 |
| Bemor Building Contractors Limited | Construction | 1975 |
| Bemor Building Services Limited | Construction | 1994 |
| Bemor Limited | Construction | 2023 |
| Benefit Services Ltd | Public administration | 2018 |
| Bensan & Daughter Limited | Wholesale & retail | 2018 |
| Bernadette Enterprise Ltd | Hospitality | 2025 |
| Bertsy Productions Limited | Arts & recreation | 2019 |
| Bespoke RT Ltd | Manufacturing | 2022 |