| 10 Dining Street Limited | Hospitality | 2024 |
| 114 Artist Management Limited | Administrative & support | 2022 |
| 13STRATEGYEXPERTS Ltd | Wholesale & retail | 2024 |
| 1M15 Properties Ltd | Real estate | 2026 |
| 22 Chalcott GDN Ltd | Professional & scientific | 2023 |
| 2D Building Ltd | Construction | 2019 |
| 2D Properties (SPV) Ltd | Real estate | 2025 |
| 2T Investments Ltd | Real estate | 2024 |
| 300 Yards of Film Ltd | Information & communication | 2018 |
| 33 Consultancy Ltd | Professional & scientific | 2021 |
| 37DOWN Ltd | Real estate | 2021 |
| 3B Design and Print Limited | Manufacturing | 2003 |
| 3D Printed Classic Car Parts Limited | Wholesale & retail | 2021 |
| 3K Electronic Designs Ltd | Information & communication | 2017 |
| 4&5 Chapel Walk Management Company Limited | Households | 2019 |
| 40 Tetherdown Management Company Ltd | Real estate | 2013 |
| 473 Automation Ltd | Information & communication | 2026 |
| 6T Commercial Limited | Real estate | 2020 |
| 7557 Property Ltd | Real estate | 2023 |
| A & a Building Surveyors Limited | Professional & scientific | 2002 |
| A + D Studio Limited | Professional & scientific | 2008 |
| A Jennings Ltd | Other services | 2017 |
| A Mind to Perform Ltd | Arts & recreation | 2009 |
| A&A Modern Properties Ltd | Real estate | 2023 |
| A&C Green Ventures Limited | Financial services | 2025 |
| A.C.& M. Limited | Administrative & support | 2005 |
| A.W.R. Houghton & SON Limited | Agriculture & fishing | 1946 |
| A1 Cabs Uppingham Limited | Transport & logistics | 2024 |
| A1 Taxis Uppingham Limited | Transport & logistics | 2023 |
| A1PLUMBING.RUTLAND Ltd | Energy | 2018 |
| AA & B Living Limited | Arts & recreation | 2022 |
| Aaron DE Meyer Brands Limited | Wholesale & retail | 2025 |
| ABA Property Investment Ltd | Financial services | 2023 |
| Abacus Hire Centre Midlands Limited | Administrative & support | 2003 |
| ABC (Oxford) Limited | Construction | 2013 |
| Abhb Consulting Ltd | Wholesale & retail | 2024 |
| ABL Braunston Ltd | Hospitality | 2024 |
| ABL Market Overton Ltd | Hospitality | 2024 |
| Absolute Care (UK) Limited | Health & social care | 1998 |
| Academy of Sound Therapy Ltd | Education | 2025 |
| Accelerate Team Ltd | Financial services | 2022 |
| Ace Support Services Limited | Other services | 1994 |
| Acorn Consulting (Rutland) Ltd | Professional & scientific | 2019 |
| Action Management Services Limited | Administrative & support | 1987 |
| Active Healthcare (Midlands) Ltd | Wholesale & retail | 2018 |
| Active Mobility Limited | Administrative & support | 2001 |
| Adam Ryan Ltd | Professional & scientific | 2018 |
| Adamo Property Investments Limited | Manufacturing | 2016 |
| Adams & Sons Limited | Wholesale & retail | 1987 |
| Adams Portraits Ltd | Arts & recreation | 2020 |
| Adiscc Limited | Professional & scientific | 2024 |
| Adivy Ltd | Other services | 2026 |
| Adroit-E Monitor Limited | Education | 2008 |
| Adroit-E Research Technologies Limited | Professional & scientific | 2004 |
| Advantage Flight Support Ltd | Administrative & support | 2007 |
| Aegis Personal Protection Ltd | Administrative & support | 2025 |
| AFFM98 Ltd | Administrative & support | 2025 |
| Agath Limited | Wholesale & retail | 2024 |
| AGR Fitness Limited | Arts & recreation | 2011 |
| Agri-Assess Limited | Professional & scientific | 2015 |
| Aimy Ltd | Wholesale & retail | 2025 |
| Aitkens Media Ltd | Professional & scientific | 2014 |
| Ajroakham Limited | Wholesale & retail | 2026 |
| Akar 68 Ltd | Hospitality | 2024 |
| Akas 23 Limited | Wholesale & retail | 2022 |
| Akas 86 Ltd | Hospitality | 2024 |
| Alchemedia Group Ltd | Information & communication | 2020 |
| Alderman Accountants Limited | Professional & scientific | 2017 |
| Alderney Race Limited | Professional & scientific | 2012 |
| Alex Blaga Ltd | Wholesale & retail | 2023 |
| Allfocal Optics Limited | Information & communication | 2022 |
| Allweald Management Limited | Hospitality | 1988 |
| Ally's Angels Limited | Financial services | 2023 |
| Almanac Ventures Limited | Financial services | 2024 |
| Alternative Investment Options Ltd | Wholesale & retail | 2024 |
| Alternative Stories Ltd | Arts & recreation | 2022 |
| Amalgamated Pump Engineering Ltd. | Manufacturing | 2018 |
| Amanet Ltd | Information & communication | 1999 |
| Ampersand MK2 Ltd | Other services | 2026 |
| Amsi London Ltd | Wholesale & retail | 2025 |
| Amsm Consulting Ltd | Professional & scientific | 2022 |
| Andrew Belson Ltd | Professional & scientific | 2024 |
| Angela Harding Ltd | Arts & recreation | 2012 |
| Angela Short Consulting Limited | Professional & scientific | 2015 |
| Anglian Orthopaedics Limited | Health & social care | 2022 |
| Anglo Call Systems Limited | Health & social care | 1996 |
| Anker Utility Services Limited | Construction | 2013 |
| Anomer BIO Ltd | Professional & scientific | 2024 |
| Anscombe Woods Management Limited | Construction | 2001 |
| Antepotens Limited | Professional & scientific | 2026 |
| Antique Automobile Investments Limited | Wholesale & retail | 2013 |
| Anywhere Anytime Anything Services Ltd | Professional & scientific | 2025 |
| Apeiros Europe Limited | Information & communication | 2016 |
| Apeiros Holdings Ltd | Financial services | 2020 |
| Apeiros Innovation Limited | Information & communication | 2023 |
| Appetitus Ltd | Wholesale & retail | 2006 |
| AR & R Ltd | Construction | 2026 |
| Arbutus House Ltd | Hospitality | 2012 |
| ARC Detail Ltd | Professional & scientific | 2025 |
| Architectural Design & Systems Limited | Professional & scientific | 2013 |