| 21 Manville Road Flat Management Company Limited | Households | 1990 |
| 2D-3D CAD Services Limited | Information & communication | 2017 |
| 7 Stars Properties Ltd | Real estate | 2026 |
| 757 Homes Limited | Real estate | 2004 |
| A & C Mason Consulting Limited | Information & communication | 2014 |
| A & N Consultants Limited | Professional & scientific | 2024 |
| A & T Brothers NE Ltd | Hospitality | 2026 |
| A 6 Assessment Ltd | Professional & scientific | 2010 |
| A B Completions Limited | Construction | 2021 |
| A P Training (NE) Limited | Professional & scientific | 2022 |
| A T & P Holdings (2022) Ltd | Administrative & support | 2022 |
| A T & P Holdings Ltd | Administrative & support | 2021 |
| A T & P Investments Ltd | Financial services | 2021 |
| A.T. & P Rentals Ltd. | Administrative & support | 1988 |
| AB Property Services (NE) Limited | Real estate | 2020 |
| AB Rigging and Lifting Ltd | Construction | 2026 |
| ABF Site Services UK Ltd | Construction | 2022 |
| Accord Agreement & Support Ltd | Health & social care | 2009 |
| Active Business Protection Limited | Financial services | 2022 |
| Active Mortgage Services Limited | Financial services | 2002 |
| Acuity Vision Care Limited | Professional & scientific | 2015 |
| Acuity Vision Properties Limited | Hospitality | 2022 |
| ADO16.INFO Limited | Other services | 2016 |
| Adorabella Bowtique Ltd | Wholesale & retail | 2025 |
| AEE Solutions Limited | Professional & scientific | 2019 |
| Agdv Properties Limited | Construction | 2019 |
| AKG Richardson Ltd | Professional & scientific | 2021 |
| Akintdistributors Ltd | Wholesale & retail | 2022 |
| Albatross Kitchen Limited | Hospitality | 2022 |
| Alexandra Handmade Ltd | Manufacturing | 2021 |
| Alfjak Developments Limited | Wholesale & retail | 2012 |
| Alia-Group Ltd | Construction | 2019 |
| Alitheo's & Co Properties Ltd | Real estate | 2019 |
| Alitheos Bar Ltd | Hospitality | 2018 |
| Allan Passmore Joinery Limited | Construction | 2003 |
| Alldayengineering Ltd | Manufacturing | 2025 |
| Allergy Support Limited | Health & social care | 2022 |
| Allied Management Limited | Real estate | 1985 |
| Allied Referrals Ltd | Real estate | 2023 |
| Amanda Russell Clinical Coding Consultancy Limited | Information & communication | 2019 |
| Amerston Consulting Ltd | Professional & scientific | 2013 |
| Andrew Muir Town Planning Limited | Professional & scientific | 2022 |
| APERTURE2000 Limited | Professional & scientific | 2018 |
| Apex Construction & Civil Engineering Limited | Construction | 2025 |
| Apex Lift Solutions Ltd | Construction | 2025 |
| Apgt Ltd | Wholesale & retail | 2017 |
| Apollo Contracting Ltd | Hospitality | 2026 |
| Applegarth Developments Limited | Construction | 1998 |
| Applegarth Limited | Construction | 2016 |
| Arran Motson Planning Solutions Ltd | Construction | 2025 |
| Arthur Pearce Limited | Real estate | 1959 |
| Ashley Clements Joinery Limited | Construction | 2018 |
| Asree Ltd | Professional & scientific | 2026 |
| Aston Building Services Ltd | Construction | 2008 |
| AT & P (Topco) Ltd | Financial services | 2025 |
| Atech Engineering Services Ltd | Professional & scientific | 2023 |
| ATL Renewables Ltd | Manufacturing | 2022 |
| Atlantic Engineering (UK) Ltd | Construction | 2015 |
| Atomix Educational Trust | Education | 2017 |
| Atozthrifting Ltd | Wholesale & retail | 2026 |
| Auction House Tees Valley Limited | Real estate | 2012 |
| Aurora Access Limited | Construction | 2009 |
| Aviator Sports and Live Lounge Ltd | Hospitality | 2025 |
| AWP Holdings Limited | Financial services | 2022 |
| B & a Ceramic Tiling Limited | Construction | 2001 |
| B & R Sahota Limited | Wholesale & retail | 2017 |
| B Mays Plumbing and Heating Ltd | Construction | 2025 |
| Badger Perrow Ltd | Manufacturing | 2014 |
| Badger's Bar 2025 Limited | Hospitality | 2025 |
| Baker Street Hair Salon Ltd | Financial services | 2021 |
| Barnes Transport Services Ltd | Transport & logistics | 2022 |
| Bartstachal Consulting Ltd | Information & communication | 2019 |
| Beau Hairdressing (North Yorkshire) Limited | Other services | 2019 |
| Beauty Bids Limited | Wholesale & retail | 2025 |
| Beckside Engineering Services Ltd | Professional & scientific | 2024 |
| Bedlington Mixology Limited | Hospitality | 2021 |
| BEE Property Solutions Ltd | Real estate | 2018 |
| Beesmart IT Limited | Information & communication | 2022 |
| Belle Enhance Aesthetics Limited | Other services | 2024 |
| Belmont Farm Cottage Limited | Other services | 2026 |
| Belmont View Limited | Health & social care | 2007 |
| BEN Johansen Building Ltd | Construction | 2024 |
| BEN Scotty Limited | Construction | 2025 |
| Bernice Paul Ltd | Real estate | 2025 |
| Berry Management Consulting Limited | Professional & scientific | 2020 |
| Betterhome Builders Merchants Limited | Administrative & support | 1988 |
| Between Guests Limited | Administrative & support | 2026 |
| BH Aviation Training Solutions Ltd | Transport & logistics | 2022 |
| BHA Futures Ltd | Professional & scientific | 2023 |
| Birkbrow Leisure Limited | Wholesale & retail | 2016 |
| Birkbrow Motor Company Limited | Wholesale & retail | 2003 |
| Birth Trauma North East CIC | Health & social care | 2024 |
| BJP Developments Limited | Administrative & support | 2004 |
| BJP Home Support Limited | Other services | 2009 |
| BJP Homes Limited | Construction | 2015 |
| BJP Leisure Limited | Hospitality | 2019 |
| Black Sheep Branding Ltd | Professional & scientific | 2023 |
| Blue Mongoose Group Ltd | Professional & scientific | 2020 |
| Bombus Ecology Ltd | Professional & scientific | 2021 |
| Booth Property Management Limited | Real estate | 2003 |