| 3 Whitehall Whitby Limited | Hospitality | 2017 |
| 369 Health Limited | Health & social care | 2020 |
| 3DDENT Ltd | Health & social care | 2025 |
| 52B.CONSULTING Limited | Professional & scientific | 2015 |
| 888 Properties (North East) Ltd | Real estate | 2014 |
| A & D Building Services (Grimsby) Limited | Construction | 2009 |
| A B S Construction (Northeast) Ltd. | Administrative & support | 2019 |
| A C Movers Ltd | Transport & logistics | 2021 |
| A Lane Services Limited | Health & social care | 2023 |
| A Legge Property Ltd | Real estate | 2023 |
| A&S NE Ltd | Wholesale & retail | 2026 |
| A.H.Rutherford | | 1990 |
| A.Middleton Limited | Other services | 2023 |
| A.W. Moffitt & Company Limited | Real estate | 1999 |
| Aaustin Engineering Limited | Professional & scientific | 2017 |
| ABC Psychological Therapy Services Limited | Other services | 2019 |
| Aberwood Developments Limited | Real estate | 1994 |
| Acespec Ltd | Professional & scientific | 2015 |
| Addiethebaddy Ltd | Construction | 2024 |
| Aegis Industrial Ltd | Professional & scientific | 2026 |
| Aerial Access Hire Limited | Wholesale & retail | 2017 |
| Aerial Commercials Limited | Wholesale & retail | 2018 |
| Aforsale Ltd | Real estate | 2020 |
| AFS Financial Limited | Financial services | 2010 |
| Agility HR (UK) Ltd | Administrative & support | 2018 |
| Aimz Properties Ltd | Real estate | 2021 |
| Ajks Design Limited | Administrative & support | 2017 |
| AJR Features Limited | Information & communication | 2014 |
| AJT Offshore Engineering Limited | Professional & scientific | 2022 |
| AK Cleaning Solutions (North East) Limited | Administrative & support | 2021 |
| Aletting Ltd | Real estate | 2020 |
| Alexander Commercial Services Ltd | Professional & scientific | 2025 |
| ALL That I AM UN Limited | Financial services | 2014 |
| Alps Electrical Ltd | Energy | 2022 |
| Alto Hire Ltd | Real estate | 2022 |
| AMS Integrity Ltd | Construction | 2024 |
| Amst Ltd | Real estate | 2011 |
| Anandas Gourmet Ltd | Manufacturing | 2013 |
| Anderson Offshore Services Ltd | Transport & logistics | 2022 |
| Andersons Locksmith Ltd | Administrative & support | 2019 |
| Andersons Property Limited | Real estate | 2017 |
| Andrew Golightly Limited | Manufacturing | 1978 |
| Andrew Milburn Joinery Limited | Administrative & support | 2017 |
| Andt Inspection Services Ltd | Professional & scientific | 2022 |
| AP Electrical Services (1981) Ltd | Construction | 2010 |
| Apex Inhalation UK Limited | Wholesale & retail | 2024 |
| Apex Weld Ltd | Manufacturing | 2026 |
| AR Training 6 Ltd | Education | 2024 |
| Architectural Building Consultants Limited | Professional & scientific | 2003 |
| Archman Geoconsultancy Ltd | Professional & scientific | 2021 |
| Arnsgill Construction Ltd. | Construction | 2009 |
| Art of Disco Ltd | Manufacturing | 2020 |
| Assudani Properties Ltd | Real estate | 2023 |
| Assure-I Limited | Professional & scientific | 2026 |
| Atallah Medical Ltd | Health & social care | 2022 |
| Atkinsons Professional Window Cleaning Limited | Administrative & support | 2017 |
| Atomic Beers Ltd | Wholesale & retail | 2024 |
| Aurix EAR Care Limited | Health & social care | 2026 |
| Autosmith N.E Limited | Wholesale & retail | 2022 |
| Avocet Natural Capital PLC | Manufacturing | 2015 |
| AW Problem Solving Systems Ltd | Professional & scientific | 2025 |
| Axria Investments Ltd | Real estate | 2020 |
| B & C Legal Reports Ltd. | Professional & scientific | 2023 |
| B & C Medical Services Limited | Administrative & support | 2016 |
| Badgermanor Limited | Professional & scientific | 2012 |
| Bailey Property Management Limited | Real estate | 1996 |
| Barbaro Stud Limited | Agriculture & fishing | 2020 |
| BE Engaged Safety Ltd | Professional & scientific | 2014 |
| BE Informed Ltd | Health & social care | 2022 |
| Beaumont (Brothers) Limited | Construction | 2017 |
| Beauty by Annabelle Ltd | Other services | 2026 |
| Beechtree Court Residents Association Limited | Households | 1989 |
| Belaw Farming | Agriculture & fishing | 2012 |
| Blackhouse (UK) Ltd | Hospitality | 2010 |
| Blackridge Stone Ltd | Health & social care | 2025 |
| Blasthaus Ltd | Manufacturing | 2021 |
| Blue Sky Career Coaching Ltd | Professional & scientific | 2012 |
| Bluebell Estate One Management Limited | Real estate | 1985 |
| Bluebell Estate Two Management Limited | Real estate | 1985 |
| Bozztech Offshore Limited | Professional & scientific | 2017 |
| Bramley (2007) Limited | Health & social care | 2005 |
| Bramley Court (Care Homes) Limited | Health & social care | 2004 |
| Brandi Studio Ltd | Professional & scientific | 2025 |
| Brandlings Yarm Management Ltd | Households | 2026 |
| Bridecourt Limited | Construction | 1971 |
| Bridgewater Manor Management Company Limited | Administrative & support | 2007 |
| Brittains Garage (Yarm) Limited | Wholesale & retail | 2012 |
| Bronson Commercials Ltd | Wholesale & retail | 2025 |
| Broomco (4250) Limited | Construction | 2012 |
| Bullseye PR Consultants Ltd | Manufacturing | 2019 |
| Bumble Aesthetics Ltd | Other services | 2025 |
| Bumble Micropigmentation Ltd | Other services | 2025 |
| Burlington House Eaglescliffe Management Company Limited | Households | 2004 |
| C.R.Westwood Limited | Professional & scientific | 2011 |
| C2 Developments (North East) Limited | Construction | 2019 |
| C2 Electrical Solutions Limited | Construction | 2010 |
| C2 Plumbing Solutions Limited | Construction | 2018 |
| C2 Property Development Limited | Construction | 2016 |
| Café Nossa Limited | Wholesale & retail | 2020 |
| Calabac Ltd | Professional & scientific | 2018 |