| (Mexes) Metals Execution Services Limited | Financial services | 2012 |
| 100% Club Group Ltd | Other services | 2023 |
| 10ANTS Property Limited | Real estate | 2025 |
| 11 2 11 Ltd | Wholesale & retail | 2021 |
| 12TH MAN Services and Solutions Ltd | Information & communication | 2012 |
| 1619 Digital Ltd | Information & communication | 2014 |
| 19750283 Limited | Financial services | 2025 |
| 1PMM Ltd | Hospitality | 2015 |
| 1XV Consultancy Ltd | Education | 2016 |
| 22 Main Street Ltd | Real estate | 2022 |
| 229 Ltd | Professional & scientific | 2022 |
| 233 Addiscombe Road Management Limited | Households | 2002 |
| 23CCC Limited | Information & communication | 2006 |
| 2612 Limited | Professional & scientific | 2025 |
| 3 Park Hill Management Company Limited | Households | 2025 |
| 360 Advertising & Marketing Limited | Professional & scientific | 2004 |
| 360 Media Group Ltd | Information & communication | 2019 |
| 399 Anlaby Management Ltd | Extraterritorial | 2009 |
| 3A4E Limited | Professional & scientific | 2020 |
| 3M Property Ltd | Construction | 2013 |
| 3TE Limited | Real estate | 2024 |
| 3TP Developments Ltd | Construction | 2025 |
| 4TTUDE Enterprises Limited | Professional & scientific | 2010 |
| 50 Trades of Gray Ltd | Construction | 2022 |
| 60 High Street, ST. Martins (Stamford) Management Company Limited | Households | 2013 |
| A & J Quant Capital Ltd | Extraterritorial | 2025 |
| A & K Associates Limited | Professional & scientific | 2004 |
| A & N Greaves GAS Services Ltd | Administrative & support | 2023 |
| A and D Wellness Group Ltd | Health & social care | 2025 |
| A Goodall Consulting Ltd | Professional & scientific | 2021 |
| A Targeted Approach Limited | Administrative & support | 2018 |
| A&J Mobile Tech Ltd | Information & communication | 2019 |
| A&Pw Holdings Ltd | Financial services | 2022 |
| A.J.Pledger and Co. (Metals) Limited | Professional & scientific | 1969 |
| A.M I.T. Integration Consulting Ltd. | Information & communication | 2022 |
| Abacus (Kent) Operations Limited | Real estate | 2018 |
| Abarchitectural Ltd | Professional & scientific | 2021 |
| Abbey Commercial Developments Limited | Construction | 1989 |
| Abbey Commercial Investments 2 Limited | Construction | 2019 |
| Abbey Commercial Investments Limited | Real estate | 1947 |
| Abbey Commercial Investments Propco Limited | Real estate | 2021 |
| Abbey Grid Support Limited | Construction | 2022 |
| Abbey Grid Support Systems Limited | Construction | 2023 |
| Abbey Investment Holdings Limited | Real estate | 2015 |
| Abbey Power Generation Limited | Energy | 2010 |
| Abbey Power Group Ltd | Energy | 2016 |
| Abbey Power Investments Limited | Financial services | 2012 |
| Abbey Power Reserve Balderton Ltd | Energy | 2022 |
| Abbey Power Reserve Limited | Extraterritorial | 2011 |
| Abbey Power Solutions Limited | Energy | 2011 |
| ABC Taxis Stamford Ltd | Transport & logistics | 2019 |
| Abel Brown Advice Ltd | Professional & scientific | 2013 |
| Above and Beyond Drone Services UK Ltd | Professional & scientific | 2025 |
| AC Services (Peterborough) Limited | Other services | 2007 |
| Accounts Rescue Ltd | Extraterritorial | 2018 |
| ACD Wealth Management Ltd | Real estate | 2015 |
| Ace Cabs Stamford Ltd | Transport & logistics | 2012 |
| Acer Decorating Ltd | Real estate | 2021 |
| Acorn Childcare Centre Limited | Education | 2013 |
| Actechivate Software Ltd | Information & communication | 2026 |
| Active Golf Projects Ltd | Administrative & support | 2020 |
| Active Interior Solutions Ltd | Construction | 2017 |
| Active Performance UK Ltd | Other services | 2018 |
| Activities Venture Limited | Arts & recreation | 2020 |
| AD Workplace Services Limited | Construction | 1998 |
| Adam Frost Studio Ltd | Arts & recreation | 2025 |
| Addo Events Limited | Other services | 2019 |
| ADE Rowbotham Limited | Information & communication | 2007 |
| Adjuvo Energy Limited | Professional & scientific | 2013 |
| ADL Partners (UK) Ltd | Administrative & support | 2014 |
| Adventure Nene Ltd | Arts & recreation | 2018 |
| Adventus Homes Ltd | Construction | 2023 |
| Adviserly Network Limited | Other services | 2026 |
| AG & KG Properties Limited | Real estate | 2021 |
| AG Adcock Electrical Services Limited | Construction | 2021 |
| AG Plumbing and Heating (Stamford) Ltd | Construction | 2024 |
| Agnew Property Group Ltd | Real estate | 2025 |
| Aikomi UK Ltd | Information & communication | 2021 |
| Air and Dusk Hospitalities Limited | Hospitality | 2023 |
| Airtek UK Limited | Wholesale & retail | 2003 |
| Aitchison Properties Limited | Real estate | 2017 |
| AJ Singer Consultancy Ltd | Professional & scientific | 2017 |
| AKS Timber Frames Limited | Construction | 2017 |
| ALB Greek Souvlaki Ltd | Hospitality | 2025 |
| Albie Art Ltd | Arts & recreation | 2019 |
| Albion Home & Lifestyle Ltd | Wholesale & retail | 2019 |
| Alchemy (1480) Limited | Construction | 1999 |
| Alcock Gardens Ltd | Real estate | 2025 |
| Aletho Media Ltd | Information & communication | 2024 |
| Alex Clipston Ltd | Construction | 2024 |
| Alex Collins Ltd | Professional & scientific | 2025 |
| Alex Glover Property Ltd | Real estate | 2026 |
| Alex Knott Equine Ltd | Professional & scientific | 2024 |
| Alexander William Enterprises Ltd | Real estate | 2021 |
| Alexandra Johnson Interior Design Limited | Professional & scientific | 2014 |
| Alfred Poppins Ltd | Administrative & support | 2018 |
| Alfresco Lifestyle Holdings Ltd | Financial services | 2025 |
| ALI & SON Construction Management Limited | Construction | 2015 |
| Alice Reins Ltd | Manufacturing | 2013 |
| Alison Maxwell Coaching Limited | Administrative & support | 2011 |