| (Sh)Rdh Ltd | Professional & scientific | 2003 |
| 13 Apparel Ltd | Wholesale & retail | 2019 |
| 1300 Limited | Other services | 2015 |
| 1KB Software Solutions Ltd | Information & communication | 2012 |
| 1ST Leisure Limited | Construction | 2002 |
| 2026 Property Limited | Real estate | 2018 |
| 2119 Ltd | Professional & scientific | 2021 |
| 24/7 Airport Transfers Ltd | Transport & logistics | 2023 |
| 24/7 Taxi Services (Peterlee) Limited | Transport & logistics | 2010 |
| 24PROJECTS Limited | Professional & scientific | 2024 |
| 2M Food Suppliers Limited | Wholesale & retail | 2008 |
| 30 Years Limited | Financial services | 2018 |
| 32 Eldon Grove Hartlepool Limited | Real estate | 2011 |
| 33MM Ltd | Information & communication | 2022 |
| 360 Consultancy (Bucks) Limited | Professional & scientific | 2017 |
| 3D CAD Tech Ltd | Professional & scientific | 2015 |
| 3G Lettings Ltd | Real estate | 2022 |
| 4QX Limited | Construction | 2013 |
| 54 One Property Ltd | Construction | 2016 |
| 5C5V Limited | Wholesale & retail | 2025 |
| 5STAR Conservatory Roof Solutions Limited | Construction | 2023 |
| 71 North Ltd | Information & communication | 2024 |
| 7634 Xlle Ltd | Hospitality | 2023 |
| 7VEN Limited | Hospitality | 2022 |
| 814 Welding Ltd | Manufacturing | 2025 |
| A & G Electrical Distributors Limited | Wholesale & retail | 2006 |
| A & G Lighting Ltd | Wholesale & retail | 2010 |
| A & M Autos Ltd | Wholesale & retail | 2021 |
| A & S Cafe Bar Limited | Hospitality | 2018 |
| A and L Inspection Ltd | Other services | 2019 |
| A B S Financial Limited | Financial services | 2023 |
| A B SEE Solutions Ltd | Professional & scientific | 2019 |
| A Car 4U Limited | Wholesale & retail | 2019 |
| A Farrow Contract Services Limited | Financial services | 2016 |
| A K Teesside Cars Limited | Wholesale & retail | 2023 |
| A Oliver Mechanical Services Ltd | Manufacturing | 2012 |
| A Slater & SON Property Services Ltd | Construction | 2025 |
| A Vaughan Electrical Engineering Limited | Construction | 2017 |
| A&E Property Renovations Limited | Real estate | 2026 |
| A-Force Training Consultancy Limited | Education | 2012 |
| A. Glew Plastering & Rendering Ltd | Construction | 2021 |
| A.D.R. (Business Services) Limited | Professional & scientific | 1991 |
| A.E.F UK Properties Limited | Real estate | 2025 |
| A.M.L. Joinery Limited | Construction | 2025 |
| A.M.T Jointing Services Ltd | Construction | 2018 |
| A.R. Construction (NE) Ltd | Construction | 2018 |
| A1 Aggregates (Hartlepool) Ltd | Wholesale & retail | 2021 |
| A1 Instrumentation Services Ltd | Professional & scientific | 1997 |
| A1 Muckaway Limited | Water & waste | 2006 |
| A1 Performance Products Limited | Construction | 2004 |
| A1 Team Wear Limited | Other services | 2014 |
| A19 Pro Clean Ltd | Water & waste | 2024 |
| A1SAFESITE Ltd | Professional & scientific | 2023 |
| AA Lift Services Ltd | Construction | 2021 |
| AA Motors (North East) Limited | Wholesale & retail | 2016 |
| AAA Stationery (NE) Ltd | Administrative & support | 2011 |
| AAC Rigging Limited | Construction | 2017 |
| Aacables Limited | Energy | 2020 |
| AAS Financial Services Ltd | Financial services | 2022 |
| AB Estates & Rentals Ltd | Real estate | 2026 |
| Abacus 365 Solutions Limited | Professional & scientific | 2018 |
| ABC Autocare Ltd | Administrative & support | 2025 |
| Abdullah Hafez Logistics Ltd | Transport & logistics | 2025 |
| Able Operators Ltd | Transport & logistics | 2019 |
| ABR Telecoms Ltd | Information & communication | 2018 |
| Access & Engineering Ltd | Manufacturing | 2021 |
| Ace Golf Limited | Wholesale & retail | 2008 |
| ACL Business Support Services Ltd | Administrative & support | 2012 |
| ACL Holdings North East Limited | Financial services | 2026 |
| Acland Management Company Ltd | Real estate | 2020 |
| Acland Two Ltd | Construction | 2021 |
| Acom Leisure Ltd | Hospitality | 2023 |
| Acorn Rivers Limited | Real estate | 2022 |
| Acpj Properties Limited | Real estate | 2020 |
| ACT &More Limited | Health & social care | 2018 |
| Active Balance Consultancy (NE) Limited | Other services | 2018 |
| Active Documents Ltd | Information & communication | 2001 |
| Active Inclusion DF Limited | Education | 2017 |
| AD Astra Academy Trust | Education | 2014 |
| ADA Retail Limited | Wholesale & retail | 2013 |
| Adam Snowball Welding Limited | Construction | 2019 |
| Adams & Crosby Ltd | Real estate | 2023 |
| Adkw Software Architecture Limited | Information & communication | 2018 |
| ADM Sales Ltd | Wholesale & retail | 2020 |
| Adorable Home Decor Ltd | Wholesale & retail | 2025 |
| Advance Mobility Ltd | Wholesale & retail | 2021 |
| Advice at Hart CIC | Hospitality | 2019 |
| ADW Interiors Limited | Construction | 2022 |
| AEE Site Services Ltd | Manufacturing | 2025 |
| AEH Elec Limited | Energy | 2017 |
| AEP Engineering Ltd | Professional & scientific | 2012 |
| AESTHETIQUE21 Limited | Health & social care | 2025 |
| Affordable Landscapes N.E. Ltd | Administrative & support | 2016 |
| AFP Consultancy Services Ltd | Professional & scientific | 2021 |
| Afrolockssalon Limited | Other services | 2025 |
| Afrowinta Limited | Wholesale & retail | 2026 |
| AGF Group Limited | Financial services | 2019 |
| Agjr Ltd | Financial services | 2025 |
| AGR Access Limited | Professional & scientific | 2026 |
| Agricultural & Groundscare Finance Limited | Financial services | 2005 |