| HFF Agrics Limited | Administrative & support | 2022 |
| HFF Civil Engineering Limited | Construction | 2009 |
| HKJ Building Services Ltd | Construction | 2026 |
| Hodges Recycling Ltd | Water & waste | 2013 |
| Holistic Consultancy Ltd | Professional & scientific | 2012 |
| Homeshield Damp Solutions Limited | Construction | 2026 |
| Hot Sands Ltd | Extraterritorial | 2024 |
| Hotspur Technology Limited | Extraterritorial | 1986 |
| Hrzn Solutions Ltd | Professional & scientific | 2023 |
| Hsib Ltd | Wholesale & retail | 2013 |
| Hydraulic Manifolds UK Ltd | Extraterritorial | 2012 |
| I & D Construction Ltd | Construction | 2018 |
| I & D Groundworks Limited | Administrative & support | 2022 |
| IAN Bradley (Recovery) Limited | Extraterritorial | 2007 |
| ICR Consultants Limited | Extraterritorial | 2016 |
| Impact Cyber Limited | Information & communication | 2025 |
| Initial Consultancy Services Limited | Information & communication | 2017 |
| Inkwell Consulting Limited | Professional & scientific | 2023 |
| Intelligent EGG Limited | Information & communication | 2026 |
| Interdependent Money Ltd | Real estate | 2024 |
| Intu Groundworks Limited | Construction | 2019 |
| IT Assist Support & Installation Ltd | Information & communication | 2013 |
| J Armstrong Kitchens Ltd | Construction | 2015 |
| J M K Management Limited | Extraterritorial | 2015 |
| J S & V Ltd | Wholesale & retail | 2025 |
| J Tech Mechanical Services Ltd | Other services | 2024 |
| J&L ASH Ltd | Real estate | 2021 |
| J.R Bolting Ltd | Transport & logistics | 2023 |
| Jacobson P a Matthew Ltd | Professional & scientific | 2024 |
| Jarrin Consultancy Limited | Information & communication | 2011 |
| Jasw Services Ltd | Health & social care | 2025 |
| Jays Court Management Company Limited | Extraterritorial | 2024 |
| Jermaine's Retreat Ltd | Extraterritorial | 2020 |
| Jessica Nails KN Ltd | Other services | 2022 |
| JH Industrial Solutions Ltd | Construction | 2024 |
| JJM Plastering Limited | Construction | 2024 |
| JJS Recovery & Storage Ltd | Transport & logistics | 2025 |
| Jlsh Industrial Solutions Ltd | Mining & quarrying | 2026 |
| JMC Retailing Limited | Wholesale & retail | 2023 |
| JMS Property and Maintenance Limited | Construction | 2021 |
| John Grenfell & SON Limited | Health & social care | 2014 |
| John Montgomery TM (Northumberland) Limited | Construction | 2025 |
| John Purvis Engineering Limited | Other services | 2017 |
| Jonathan Clark Heating Installations Ltd | Construction | 2012 |
| Juniper Creators Ltd | Professional & scientific | 2026 |
| JV Machining Soloutions Ltd | Construction | 2021 |
| JWR North East Roofing Ltd | Construction | 2024 |
| K H S (NE) Ltd | Hospitality | 2019 |
| K L Mechanical Limited | Professional & scientific | 2024 |
| Kabel Consulting Limited | Other services | 2012 |
| Katie Calvert Limited | Other services | 2023 |
| KD ERP Solutions Ltd | Information & communication | 2018 |
| KDL Site Welding Services Limited | Manufacturing | 2017 |
| Kevin Builder Group Ltd | Construction | 2025 |
| Kevin Burt Roofing Limited | Construction | 2010 |
| Kevin Foster Funeral Services Ltd | Other services | 2018 |
| Keylock Properties Ltd | Real estate | 2025 |
| KG Fibre Services Ltd | Construction | 2021 |
| Khas Khana Ltd | Hospitality | 2017 |
| Khizer Limited | Wholesale & retail | 2012 |
| Kieron Walker Logistics Ltd | Transport & logistics | 2025 |
| Kmch Limited | Transport & logistics | 2010 |
| Knrc Ltd | Wholesale & retail | 2025 |
| KTB Property Management Ltd | Real estate | 2021 |
| L.A.B Aesthetics Ltd | Other services | 2020 |
| L.S Engineering Solutions Ltd | Construction | 2024 |
| Labratrack Ltd | Construction | 2017 |
| LAD Sealants Ltd | Construction | 2026 |
| Langan Welding Services Ltd | Manufacturing | 2022 |
| Lapp Equipment UK Ltd | Administrative & support | 2017 |
| Lascelles Hyde Limited | Professional & scientific | 2018 |
| Lawson Merchandise Ltd | Wholesale & retail | 2025 |
| Lawson Plater Ltd | Manufacturing | 2026 |
| Lb&C Joinery and Carpentry Ltd | Construction | 2025 |
| LC Access Services Ltd | Professional & scientific | 2019 |
| Leaf and Ocean Ltd | Hospitality | 2023 |
| Leafield Cottage 1964 Limited | Extraterritorial | 2014 |
| Legacy Supplies Ltd | Wholesale & retail | 2024 |
| Leyland Legacy Limited | Real estate | 2024 |
| Life in Focus Ltd | Information & communication | 2024 |
| Lion Garage Services Ltd | Wholesale & retail | 2018 |
| Literally Marketing Ltd | Professional & scientific | 2024 |
| Lktm (North East) Ltd | Extraterritorial | 2022 |
| LMP Property Group Ltd | Real estate | 2025 |
| Local Bargains Ltd | Wholesale & retail | 2025 |
| Lost & Profound Ltd | Wholesale & retail | 2021 |
| Lowes Roofing & Guttering Services Limited | Construction | 2014 |
| LRG Scaffolding Limited | Construction | 2022 |
| M & K Armstrong Services Limited | Professional & scientific | 2019 |
| M.B. Mechanical Engineering Ltd | Professional & scientific | 2020 |
| M3 Civils Limited | Construction | 2019 |
| MAC Truck UK Ltd | Hospitality | 2024 |
| Macmech Services Ltd | Professional & scientific | 2022 |
| Mactec Services (UK) Limited | Professional & scientific | 2013 |
| Mainroad Ltd | Wholesale & retail | 2009 |
| Manhattan Management Consultancy Limited | Information & communication | 2006 |
| Manners TM Limited | Construction | 2020 |
| Marconstructures Ltd | Professional & scientific | 2019 |
| Marcus Webb Golf Professional | Wholesale & retail | 1989 |
| Mariposa Communications Limited | Administrative & support | 2016 |