| JRD Fitness Ltd | Other services | 2021 |
| JRL Installations Ltd | Construction | 2010 |
| JRM Holdings NE Ltd | Real estate | 2026 |
| JRR Marketing Ltd | Information & communication | 2015 |
| JRS Safety Solutions Ltd | Professional & scientific | 2025 |
| Jrs-Fds Limited | Professional & scientific | 2013 |
| JRT Access Ltd | Construction | 2025 |
| JS Inspection Services Ltd | Professional & scientific | 2025 |
| JS Site Services Ltd | Construction | 2026 |
| Js&M Developments Ltd | Real estate | 2026 |
| JSA Collective Ltd | Wholesale & retail | 2025 |
| JSA Welding Services Ltd | Professional & scientific | 2020 |
| JSE Contracting Limited | Wholesale & retail | 2022 |
| JSH Joinery Ltd | Construction | 2025 |
| JSO Care Ltd | Education | 2022 |
| Jsod Consulting Limited | Professional & scientific | 2023 |
| JSR Rope Acces Ltd | Construction | 2019 |
| JST Consultancy Ltd | Professional & scientific | 2024 |
| JSW (UK) Ltd | Wholesale & retail | 2010 |
| JT Commercial Management Ltd | Professional & scientific | 2015 |
| JT H&S Ltd | Professional & scientific | 2026 |
| JT Irvine Ltd | Professional & scientific | 2023 |
| JT Piping Solutions Ltd | Manufacturing | 2023 |
| JT Wind Services Ltd | Manufacturing | 2025 |
| JTA Construction Sevices Ltd | Construction | 2025 |
| JTB Telecommunications Ltd | Construction | 2023 |
| Jtcproductions Limited | Information & communication | 2024 |
| Jtjl Limited | Construction | 2025 |
| Jtmechsolutions Ltd | Manufacturing | 2025 |
| JTS Safety Ltd | Professional & scientific | 2025 |
| JTX Property Management Limited | Households | 2024 |
| Jubilee Solutions Limited | Administrative & support | 2024 |
| Juiced Studio Ltd | Professional & scientific | 2019 |
| Juicy Nails Limited | Other services | 2014 |
| Juicybites.Co.Uk - Ltd | Hospitality | 2026 |
| Julia at Stewarts Ltd | Other services | 2013 |
| Julie Nic’S Health Care Ltd | Health & social care | 2023 |
| Junction Investments Ltd | Real estate | 2013 |
| Jurassic Supps Ltd | Manufacturing | 2025 |
| Just Card Payments Ltd | Financial services | 2021 |
| Just Fast Food Ltd | Hospitality | 2025 |
| Just Pottering Ltd | Arts & recreation | 2019 |
| Just TRY AI Ltd | Information & communication | 2023 |
| JVB Access Ltd | Professional & scientific | 2019 |
| Jvpartner Practice Chester-Le-Street Limited | Health & social care | 2025 |
| JW & Sons Ltd | Water & waste | 2025 |
| JW & Sons Rigging and Lifting Solutions Ltd | Construction | 2025 |
| JW Endeavour Limited | Hospitality | 2023 |
| JW Hardware Ltd | Wholesale & retail | 2020 |
| JW Planning Limited | Professional & scientific | 2020 |
| JWC Controlled Environment Services Limited | Construction | 2024 |
| JWE Industrial Services Ltd | Construction | 2018 |
| Jwill Insulation Ltd | Construction | 2026 |
| JWK (North East) Limited | Construction | 2024 |
| Jwmpf Ltd | Professional & scientific | 2025 |
| Jwresale Ltd | Wholesale & retail | 2025 |
| JWT21 Limited | Hospitality | 2016 |
| K & D Engineering Services Ltd | Professional & scientific | 2020 |
| K & G Group Ltd | Transport & logistics | 2020 |
| K & K Hardware (Ormesby) Limited | Wholesale & retail | 2015 |
| K & S Financial Management Ltd | Financial services | 2011 |
| K & T (NE) Ltd | Real estate | 2023 |
| K - LEK Limited | Manufacturing | 2003 |
| K and R Barber Shop Ltd | Other services | 2023 |
| K Brodie Safety Ltd | Construction | 2024 |
| K L S(Ne) Ltd | Health & social care | 2022 |
| K R Companies Ltd | Hospitality | 2019 |
| K S Retail Stores Limited | Wholesale & retail | 2023 |
| K&A Sellista Ltd | Wholesale & retail | 2024 |
| K&J Global Ltd | Wholesale & retail | 2026 |
| K&L Plumbing Limited | Construction | 2012 |
| K&M Your Properties Ltd | Real estate | 2022 |
| K&W Foods Ltd | Hospitality | 2019 |
| K. Bilendi Ltd | Wholesale & retail | 2023 |
| K. C. Inspections Limited | Professional & scientific | 2012 |
| K.C.S Curries Limited | Hospitality | 2022 |
| K.Kollection Ltd | Wholesale & retail | 2025 |
| K.O.G Capital Limited | Information & communication | 2013 |
| K1 Properties Limited | Real estate | 2024 |
| K1 Shop Cargo Ltd | Wholesale & retail | 2025 |
| K2 Cash and Carry 2023 Ltd | Wholesale & retail | 2023 |
| KA Online Sales Limited | Wholesale & retail | 2023 |
| KAA Distributions Ltd | Wholesale & retail | 2026 |
| Kabul’S Cuisine Ltd | Hospitality | 2024 |
| Kaddys Newsagents Ltd | Wholesale & retail | 2023 |
| Kader Football Club Limited | Arts & recreation | 2011 |
| Kafe Zone Limited | Wholesale & retail | 2025 |
| Kahlon 1957 Limited | Extraterritorial | 2013 |
| Kahst Limited | Professional & scientific | 2021 |
| KAL Safety Management Ltd | Manufacturing | 2023 |
| Kalapala Eats & Treats Ltd | Hospitality | 2026 |
| Kalemah Ltd | Education | 2025 |
| Kallistia Aesthetics Clinic Ltd | Manufacturing | 2024 |
| Kalsoom Properties Ltd | Real estate | 2019 |
| Kamzfy Ltd Ltd | Real estate | 2023 |
| Kang-Tee Ltd | Health & social care | 2022 |
| Karas Cutz Limited | Other services | 2021 |
| Karda Tech Limited | Wholesale & retail | 2025 |
| Karen Lowes Ltd | Health & social care | 2007 |
| Karin Downs TP Ltd | Health & social care | 2012 |