| 121 Consultant Services Limited | Professional & scientific | 2017 |
| 121 Express Garments Limited | Manufacturing | 2017 |
| 121 Professional Services Limited | Professional & scientific | 2026 |
| 147 Design Limited | Professional & scientific | 2002 |
| 1817 MSC Ltd | Wholesale & retail | 2020 |
| 2 Ridley Road Management Limited | Households | 2008 |
| 41LMR Limited | Extraterritorial | 2018 |
| 4X4 Accessories & Tyres Limited | Wholesale & retail | 2002 |
| 5 Acres Canine Ltd | Other services | 2023 |
| 57 South Parade (Northallerton) Management Company Limited | Households | 2015 |
| 751.ATLANTIC Ltd | Professional & scientific | 2024 |
| 76084 Locomotive Company Limited | Transport & logistics | 1997 |
| 80NOIR Limited | Wholesale & retail | 2025 |
| 80NOIR Ultra Limited | Manufacturing | 2014 |
| A and M Business Investor Services Ltd | Financial services | 2013 |
| A J W Engineering Ltd | Construction | 2004 |
| A M Steel Buildings Ltd | Construction | 2023 |
| A. Thompson Consulting Limited | Construction | 2003 |
| A.J. & J.J. Readman Limited | Construction | 2003 |
| A.N.B. Limited | Real estate | 2001 |
| A.Wade & Co. (Northallerton) Limited | Transport & logistics | 1970 |
| Aals Holdco Limited | Financial services | 2026 |
| Aaminah Snowdon Art Limited | Arts & recreation | 2017 |
| Aapa Life Limited | Manufacturing | 2026 |
| AB Power Systems Ltd | Professional & scientific | 2014 |
| Abbey Acorn Developments Limited | Wholesale & retail | 2002 |
| Abbington Blake Associates Ltd | Administrative & support | 2018 |
| ABC Book Keeping & Accounting Services Limited | Professional & scientific | 2003 |
| ABC Properties (NE) Limited | Real estate | 2016 |
| ABF Electrical & Solar Limited | Wholesale & retail | 2024 |
| ABS Lifting Ltd | Construction | 2022 |
| AC Attractions Limited | Arts & recreation | 2011 |
| Access Ladders (UK) Limited | Manufacturing | 1994 |
| Access Ladders Limited | Extraterritorial | 2011 |
| ACS Legal Recruiting Ltd | Administrative & support | 2025 |
| ACW HUI Orthopaedics Limited | Health & social care | 2009 |
| AD Lund Properties Limited | Real estate | 2023 |
| Adams and Catering Ltd | Hospitality | 2024 |
| Adamson Contractors Limited | Agriculture & fishing | 2006 |
| ADH Site Surveys Limited | Professional & scientific | 2007 |
| ADR Properties (Yorkshire) Ltd | Real estate | 2022 |
| Advance AVP Limited | Information & communication | 2009 |
| Adventure Toys Holdings Ltd | Financial services | 2024 |
| Adventure Toys Ltd | Wholesale & retail | 2008 |
| AFE Delivery Ltd | Transport & logistics | 2023 |
| Agri Plant Holdings Limited | Financial services | 2022 |
| Agri Plant Solutions Limited | Administrative & support | 2009 |
| Agrikit Limited | Manufacturing | 1999 |
| AH Estate Services Limited | Real estate | 2024 |
| AI Customworks Limited | Information & communication | 2025 |
| AIC Hospitality Ltd | Hospitality | 2026 |
| AIC Security Ltd | Administrative & support | 2025 |
| AIL Logistics Limited | Transport & logistics | 2009 |
| AJM Financial Advice Ltd | Financial services | 2026 |
| AK Carpentry & Joinery Ltd | Manufacturing | 2025 |
| ALC Gaming Limited | Financial services | 2025 |
| Alchemy Design & Works Limited | Manufacturing | 1992 |
| Alcuin of York Ltd | Hospitality | 2013 |
| Alderborough Limited | Other services | 1994 |
| Alessandro Persano Financial Consulting Ltd | Professional & scientific | 2026 |
| Alexander Jewitt & Co. Limited | Professional & scientific | 2009 |
| Alexander Optometrists Ltd | Health & social care | 2007 |
| Align Property Partners Limited | Construction | 2016 |
| Align Property Services Limited | Construction | 2023 |
| Alive Healthcare Solutions Ltd | Administrative & support | 2023 |
| Allerton Barbers Ltd | Other services | 2023 |
| Allerton Hill Properties Limited | Real estate | 2009 |
| Allerton Pizza Ltd | Hospitality | 2025 |
| Allerton Pizzaria Ltd | Hospitality | 2026 |
| Allerton Pizzeria Limited | Hospitality | 2019 |
| Allerton Steel (Property) Limited | Real estate | 2009 |
| Allerton Steel Limited | Manufacturing | 2009 |
| Allied Fuels Limited | Wholesale & retail | 1992 |
| Alverton Bacon Supplies Limited | Wholesale & retail | 2002 |
| Alverton Press Limited | Manufacturing | 2010 |
| Amac Engineering (N.E.) Limited | Professional & scientific | 2015 |
| Ambasat Ltd | Professional & scientific | 2019 |
| Ambasense Ltd | Information & communication | 2017 |
| Ambasoft UK Ltd | Information & communication | 2015 |
| AMK Executive Search Limited | Administrative & support | 2021 |
| Anderson Properties Ltd | Real estate | 2024 |
| Andrew Allum Joinery and Construction Limited | Construction | 2019 |
| Andrew Mullen Ltd | Arts & recreation | 2014 |
| Andrew Spence Health, Safety & Risk Consultancy Ltd | Professional & scientific | 2018 |
| Andrews Scott Limited | Wholesale & retail | 2024 |
| Andy Carter Limited | Information & communication | 2012 |
| ANF Consulting Ltd | Professional & scientific | 2013 |
| Angus Morton Butchers (Richmond) Limited | Financial services | 2024 |
| Angus Morton Butchers Limited | Wholesale & retail | 2007 |
| AOA Services Limited | Health & social care | 2005 |
| Appleton Electrical Services Ltd | Construction | 2002 |
| Aqua Pool & Sauna Limited | Arts & recreation | 2025 |
| Aquatics Life Ltd | Wholesale & retail | 2025 |
| ARA Marine Consulting Ltd | Administrative & support | 2020 |
| ARB Grain Services Ltd | Manufacturing | 2026 |
| Arcadia Builders Limited | Construction | 2008 |
| Arden Fishing Club Limited | Arts & recreation | 2003 |
| Argo Farm Services Limited | Households | 2022 |
| ARK Design Services Ltd | Professional & scientific | 2023 |
| Arncliffe Farms Limited | Extraterritorial | 2002 |