| JLM Capital Ltd | Real estate | 2026 |
| JMB North East Limited | Information & communication | 2023 |
| Jmclean Property Ltd | Real estate | 2020 |
| JMF 21 Limited | Real estate | 2025 |
| JMS Events NE Ltd | Administrative & support | 2025 |
| JMS Items Ltd | Wholesale & retail | 2025 |
| JO Hand Luxury Properties & Estates Ltd | Professional & scientific | 2022 |
| JO Hand Recruitment (Teesside) Ltd | Administrative & support | 2023 |
| Joebraithwaiteaccess Ltd | Manufacturing | 2019 |
| John Alderdice & SON Limited | Professional & scientific | 2015 |
| John and Karin Brown Family Holdings Ltd | Real estate | 2019 |
| John and Karin Brown Family Partnership LLP | | 2019 |
| John Boyd Associates Limited | Professional & scientific | 1989 |
| John D Phillips Movements Ltd | Transport & logistics | 2025 |
| John Hellens (Contracts) Limited | Administrative & support | 1973 |
| Johnjax Limited | Construction | 2013 |
| Joke Properties Ltd | Real estate | 2025 |
| JON Cassidy Outfitters Ltd | Construction | 2017 |
| JON White Commercial Refinishers Limited | Wholesale & retail | 2018 |
| Jones Family Holdings Ltd | Real estate | 2017 |
| Jones Family Partnership LLP | | 2017 |
| Jordan Property Partnership LLP | | 2021 |
| Jordan Wright Engineering Limited | Manufacturing | 2021 |
| Joseph Developments Limited | Professional & scientific | 2001 |
| Joules & Pierre Ltd | Professional & scientific | 2020 |
| JP Consultancy North East Limited | Professional & scientific | 2026 |
| JP Industrial Services Ltd | Construction | 2024 |
| JR (North) Properties Ltd | Real estate | 2025 |
| JRD North East Limited | Construction | 2019 |
| JRS Electrical and Building Services N.E Ltd | Construction | 2020 |
| JS Medical Aesthetics Northeast Limited | Health & social care | 2026 |
| JS Partnership LLP | | 2020 |
| Julia Wood & Associates Limited | Other services | 2011 |
| Jupiter Design Ltd | Professional & scientific | 2022 |
| Just Jude Ltd | Wholesale & retail | 2024 |
| Just Property Matters Holdings Ltd | Real estate | 2018 |
| Just Property Matters LLP | | 2018 |
| JW Commercial Properties Limited | Real estate | 2024 |
| K & K Daly Limited | Professional & scientific | 2019 |
| K & L Topham Limited | Financial services | 2010 |
| K Miller WP Ltd | Administrative & support | 2024 |
| K W P P LLP | | 2017 |
| K&E Visions Ltd | Health & social care | 2023 |
| K1 Build Solutions Ltd | Professional & scientific | 2025 |
| K21 Vape Ltd. | Other services | 2026 |
| Kaamar Limited | Manufacturing | 2005 |
| Kaanha Treasure Limited | Wholesale & retail | 2025 |
| Kabir & Sons Meat Suppliers Ltd | Wholesale & retail | 2026 |
| Kabiyan Ltd | Real estate | 2022 |
| Kallas & Co Ltd | Health & social care | 2023 |
| Kalpavriksha Ltd | Real estate | 2023 |
| Kamlana Consultancy Limited | Health & social care | 2010 |
| Kamo's Takeaway Ltd | Hospitality | 2024 |
| Kandan Media Ltd | Wholesale & retail | 2025 |
| Kandr Consultancy Limited | Professional & scientific | 2010 |
| Kansal Ltd | Real estate | 2017 |
| Kansal Properties Ltd | Real estate | 2022 |
| KAP Rail Services Limited | Administrative & support | 2021 |
| Katie’S School of Dance Ltd | Arts & recreation | 2026 |
| Katmat Services Ltd | Professional & scientific | 2007 |
| Katwalk Kimberleys CIC | Manufacturing | 2014 |
| Katy Taylor Locum Services Limited | Wholesale & retail | 2021 |
| Kaushal Family Holdings Ltd | Real estate | 2019 |
| Kaushal Partnership LLP | | 2019 |
| KAZ by DE Unique Limited | Wholesale & retail | 2021 |
| KDS Management Services Ltd | Professional & scientific | 2023 |
| Keazo Ltd | Wholesale & retail | 2025 |
| Keelan Family Holdings Limited | Real estate | 2021 |
| Keelan Family Partnership LLP | | 2021 |
| Keeping Construction and Landscapes Ltd | Construction | 2022 |
| KELCHAPPO10 Ltd | Construction | 2025 |
| Kelcor Ltd | Professional & scientific | 2025 |
| Kempson Holdings Ltd | Real estate | 2021 |
| Keogh Family Partnership LLP | | 2022 |
| Kerai Family Holdings Ltd | Real estate | 2020 |
| Kerai Family Partnership LLP | | 2020 |
| Kessler Family Holdings Ltd | Real estate | 2017 |
| Kessler Family Partnership LLP | | 2017 |
| Key Largo Ltd | Real estate | 2018 |
| Keyarch Engineering Limited | Professional & scientific | 2010 |
| Kfky 128 Ltd | Administrative & support | 2019 |
| Kfky 456 Ltd | Wholesale & retail | 2023 |
| KHP Elite Care Ltd | Health & social care | 2025 |
| KIM Stones Limited | Real estate | 1999 |
| Kimble's Quality Homemade Food Ltd | Wholesale & retail | 2019 |
| Kimcoh Properties LLP | | 2021 |
| Kindnesshub.Com Limited | Financial services | 2023 |
| Kinetic AIU Ltd | Information & communication | 2025 |
| King Property Partnership LLP | | 2023 |
| Kingston Lettings Group LLP | | 2018 |
| Kingston Lettings Limited | Real estate | 2012 |
| Kingswood Family Partnership LLP | | 2021 |
| Kirkbride Engineering Limited | Professional & scientific | 2018 |
| KL Advisory Ltd | Professional & scientific | 2025 |
| KL Aesthetics Ltd | Health & social care | 2019 |
| KL Talent Solutions Ltd | Administrative & support | 2023 |
| Km&Jl PUB Enterprise Ltd | Hospitality | 2020 |
| Kodo Lifescience Ltd | Other services | 2023 |
| Kojagori Ltd | Health & social care | 2025 |
| Koks Equipment UK Ltd | Wholesale & retail | 2022 |