| 104 Malden Road Limited | Households | 2021 |
| 121CREATIVE Limited | Information & communication | 2024 |
| 1BIKE1WORLD Limited | Other services | 2020 |
| 1ST Choice Car and Body Repairs Limited | Wholesale & retail | 2016 |
| 2 Bakers Farm Ltd | Real estate | 2022 |
| 208 Productions Ltd | Information & communication | 2011 |
| 24FILMS Ltd | Arts & recreation | 2024 |
| 2J Consulting Limited | Professional & scientific | 2013 |
| 3 Counties Building Services Limited | Construction | 2007 |
| 300 SC Precision Engineering Ltd | Manufacturing | 2019 |
| 4 Counties Sweep and Solid Fuel Installation Ltd | Administrative & support | 2022 |
| 4 Site Electrical Services Limited | Construction | 2018 |
| 4 Wald Ltd | Real estate | 2004 |
| 4D Real Estate Limited | Real estate | 2017 |
| 4TH Wall Productions Limited | Information & communication | 2014 |
| 5NRG Group Limited | Professional & scientific | 2024 |
| 7 Nova Group Ltd | Administrative & support | 2024 |
| 8 MAC Locations Limited | Administrative & support | 2014 |
| 8MAC Limited | Administrative & support | 2013 |
| A C M Power Management Limited | Professional & scientific | 2009 |
| A Jewell GAS Engineer Ltd | Construction | 2019 |
| A L Contractors Limited | Transport & logistics | 2019 |
| A P Newman Limited | Professional & scientific | 2012 |
| A R Worboys Limited | Agriculture & fishing | 2003 |
| A&Z Barbers Limited | Other services | 2026 |
| A2Z Employment Ltd | Administrative & support | 2015 |
| Abbey Facilities Management Ltd | Construction | 2020 |
| Abbots Walk Vaping Ltd | Wholesale & retail | 2018 |
| Abbotsbridge Ltd | Wholesale & retail | 1977 |
| Abi's Trading Limited | Hospitality | 2019 |
| Able Design Ltd | Manufacturing | 2017 |
| Abmt Developments Limited | Real estate | 2016 |
| Abodo Group Ltd | Wholesale & retail | 2021 |
| ABS Auto & Tyres Limited | Wholesale & retail | 2016 |
| Ac&Dc Services Ltd | Other services | 2022 |
| ACB Electrical & Building Services Limited | Construction | 2014 |
| Accident App Ltd | Information & communication | 2025 |
| Accolade Developments Limited | Wholesale & retail | 1984 |
| Accomplish.Media Ltd | Professional & scientific | 2026 |
| Ace-Up Trading Ltd | Transport & logistics | 2020 |
| Acquired Precision Consultancy Ltd | Professional & scientific | 2017 |
| Acquired Property Limited | Real estate | 2023 |
| Acre Sulis Ltd | Extraterritorial | 2024 |
| Active Sports Coaching Ltd | Administrative & support | 2017 |
| AD HOC Partnership Building Limited | Construction | 2011 |
| Adam Schacter Design Ltd. | Administrative & support | 2008 |
| Adapt Design Ltd | Arts & recreation | 2010 |
| ADD IT UP Finance Limited | Administrative & support | 2003 |
| Addingtonblu Limited | Health & social care | 2018 |
| ADO Property Limited | Real estate | 2026 |
| Advenia Limited | Professional & scientific | 2011 |
| Aegis Management Systems Ltd | Professional & scientific | 2021 |
| Aesthetics by DR KAM Ltd | Health & social care | 2020 |
| Aesthetics by Kelly Limited | Other services | 2026 |
| Aetos Kebab Ltd | Hospitality | 2023 |
| Agilepoint Ltd | Information & communication | 2017 |
| Agilesecops Limited | Information & communication | 2024 |
| Agrt Enterprises Ltd | Construction | 2020 |
| Aiden Jones Limited | Hospitality | 2013 |
| Aircheck Holdings Ltd | Financial services | 2024 |
| Aircheck Services Compliance Ltd | Health & social care | 2023 |
| Airline Avionics Resources Ltd | Manufacturing | 2011 |
| AJ Isherwood Consulting Ltd | Professional & scientific | 2017 |
| AJ Roofing Hertfordshire Ltd | Construction | 2026 |
| Ajag Property Limited | Real estate | 2023 |
| Ajforsyth Lettings Limited | Real estate | 2023 |
| Ajforsyth Limited | Health & social care | 2017 |
| Alan Michael Baxter Consulting Limited | Professional & scientific | 2025 |
| Alban Property Investments Limited | Professional & scientific | 2012 |
| Alderstone Property Group Ltd | Real estate | 2026 |
| Alderwine Limited | Real estate | 1989 |
| Alexander Wedding Belles Ltd | Other services | 2017 |
| Alexander-Watson Consulting Ltd | Professional & scientific | 2022 |
| Alfassa Limited | Real estate | 2016 |
| ALI Brothers Travel Ltd | Administrative & support | 2023 |
| Alit Grill Ltd | Hospitality | 2024 |
| ALL Data Services Limited | Information & communication | 2021 |
| ALL Progressives Congress UK Chapter Limited | Other services | 2017 |
| Alpha MU Holdings Ltd | Financial services | 2026 |
| Alpha-One Security Services Limited | Administrative & support | 2006 |
| Alpz Grips Ltd | Information & communication | 2024 |
| Aluminium Pressings Ltd | Manufacturing | 2021 |
| Amanda Pierce Consulting Limited | Professional & scientific | 2020 |
| Ambassador House (Carlton Hill) Limited | Extraterritorial | 1995 |
| Ambio Hvac Services Ltd | Construction | 2026 |
| AMG Systems Limited | Manufacturing | 1993 |
| Amida Fire Limited | Administrative & support | 2016 |
| Ampedge Ltd | Construction | 2018 |
| Amso Holdings Ltd | Financial services | 2020 |
| Anadora Aesthetics Ltd | Health & social care | 2025 |
| Anadora Studios Limited | Other services | 2024 |
| Anaiva Entertainment Ltd | Arts & recreation | 2022 |
| Ancor Scientific Solutions Ltd | Professional & scientific | 2022 |
| Andre LA Boutique Limited | Wholesale & retail | 2000 |
| Andrea Braga Ltd | Information & communication | 2015 |
| Andrew James Eventing Ltd | Arts & recreation | 2015 |
| Anezah Limited | Health & social care | 2022 |
| Angelrays Care and Support Services Ltd | Health & social care | 2023 |
| Angelrays Consultancy Ltd | Real estate | 2014 |
| Anglia Handling Services Limited | Manufacturing | 1981 |