| J3C Property Limited | Real estate | 2021 |
| J4S Social Work Limited | Health & social care | 2019 |
| J90 Autos Ltd | Wholesale & retail | 2025 |
| JA Palmer Holdings Ltd | Real estate | 2025 |
| Jaco Holdings Ltd | Real estate | 2025 |
| Jacodia-Pab Ltd | Transport & logistics | 2026 |
| JAD Property Lettings (NO.1) Ltd | Real estate | 2020 |
| JAD Property Lettings (NO.2) Ltd | Real estate | 2020 |
| JAD Property Lettings (NO.3) Ltd | Real estate | 2020 |
| JAD Property Lettings (NO.4) Ltd | Real estate | 2020 |
| JAD Property Lettings (NO.5) Ltd | Real estate | 2022 |
| JAD Property Lettings (NO6) Ltd | Real estate | 2022 |
| Jadetree Properties Ltd | Construction | 2022 |
| JAG Investment Capital Ltd | Real estate | 2024 |
| Jalcen Limited | Professional & scientific | 1977 |
| James Kitchens Ltd | Manufacturing | 2025 |
| James Place Limited | Hospitality | 2002 |
| James Stone & SON Limited | Wholesale & retail | 1959 |
| Jamie Gaunt Enterprises Limited | Hospitality | 2018 |
| Jango Properties Ltd | Real estate | 2016 |
| Japanese Toilets Ltd | Wholesale & retail | 2025 |
| Jas'Healthcare Limited | Public administration | 2022 |
| Jason Dudley Photography Ltd | Professional & scientific | 2025 |
| Jasvik Solutions Ltd | Wholesale & retail | 2026 |
| Jawad Ahmed Properties Limited | Real estate | 2024 |
| JB Ravindran & Co. Ltd | Real estate | 2025 |
| JBD Scaffolding Ltd | Construction | 2017 |
| Jbkskd Ltd | Wholesale & retail | 2026 |
| JBM Global Trading Ltd | Wholesale & retail | 2026 |
| JCA Building Consulting Limited | Professional & scientific | 2013 |
| JCA Consulting Limited | Professional & scientific | 2026 |
| JCA Group Consulting Limited | Financial services | 2021 |
| JCN Design Services Ltd | Professional & scientific | 2017 |
| Jcsic Ltd | Information & communication | 2023 |
| JCT Property (Hull) Limited | Real estate | 2025 |
| JD Caci Limited | Manufacturing | 2017 |
| Jddk Property Limited | Real estate | 2018 |
| JDJ Solutions Limited | Information & communication | 2025 |
| JDM and Supercars Investment Limited | Wholesale & retail | 2021 |
| JDM Construction Ltd | Construction | 2009 |
| Jdmp Plumbing & Heating Ltd | Construction | 2025 |
| JDS Housing Limited | Real estate | 2024 |
| Jehawleyproperty Ltd | Households | 2025 |
| JEK Automotive Ltd | Manufacturing | 2026 |
| JET Wash North East Limited | Administrative & support | 2016 |
| Jewel Financial Services Ltd | Financial services | 2018 |
| Jewelentine Limited | Wholesale & retail | 2025 |
| JFH Social Finaghy Ltd | Other services | 2024 |
| JGH Property Ltd | Real estate | 2023 |
| JGM Systems Limited | Information & communication | 2025 |
| JH Technology Services Ltd | Information & communication | 2012 |
| JHM Consultancy Ltd | Construction | 2025 |
| JIF Stroke Care Limited | Health & social care | 2024 |
| Jigsaw Property Services (Staffordshire) Limited | Construction | 2022 |
| Jinhe Limited | Hospitality | 2020 |
| JJS Services Group Limited | Construction | 2022 |
| JJT Investment Group Limited | Other services | 2023 |
| Jkmk Investment Ltd | Financial services | 2026 |
| JL Gardening and Maintenance Ltd | Other services | 2018 |
| JL Property Maintenance Limited | Construction | 2014 |
| JLE Garden Maintenance Limited | Professional & scientific | 2024 |
| JM Mechanical Limited | Professional & scientific | 2024 |
| JMB Health Consultancy Ltd | Health & social care | 2011 |
| JMM K9 Ltd | Administrative & support | 2024 |
| JMS Lincoln Limited | Construction | 2008 |
| JNN Holdings Ltd | Financial services | 2019 |
| Jnsc Properties Limited | Real estate | 2023 |
| JO & JO Pizza Ltd | Hospitality | 2026 |
| Jo.Wa Autos Ltd | Wholesale & retail | 2026 |
| Joanna Regan Limited | Professional & scientific | 2015 |
| Joao Muel Limited | Health & social care | 2008 |
| Jobern Properties Limited | Real estate | 2025 |
| JOE & SON Cleaning Ltd | Administrative & support | 2024 |
| JOE Chilton Limited | Wholesale & retail | 2021 |
| JOE Humphries PT Ltd | Education | 2023 |
| Joe's Gleaming Ovens Ltd | Administrative & support | 2023 |
| Joe's Quality Meats Ltd | Wholesale & retail | 2020 |
| Joggi Ltd | Hospitality | 2026 |
| John Harvey Developments Ltd | Construction | 2023 |
| John Martin Transport Consultancy Ltd | Professional & scientific | 2024 |
| John Roberts & SON Limited | Wholesale & retail | 1988 |
| John Rodgers Hire Limited | Administrative & support | 2019 |
| John Rodgers Limited | Construction | 2015 |
| Johnsons Day Nursery Trentham Ltd | Education | 2019 |
| Joka Retail Ltd | Wholesale & retail | 2024 |
| Jones Painting Ltd | Construction | 2019 |
| Joseph Mcclune & SON Limited | Construction | 1998 |
| Jowat (UK) Limited | Wholesale & retail | 2001 |
| Joyful Mind North East Community Interest Company | Health & social care | 2026 |
| JPC Fleets Limited | Transport & logistics | 2025 |
| JPD Trading Ltd | Wholesale & retail | 2022 |
| JR Motor Sales Limited | Wholesale & retail | 2025 |
| JRC Building Services Limited | Construction | 2011 |
| JRI Projects Ltd | Real estate | 2024 |
| JRJ (NW) Ltd | Transport & logistics | 2022 |
| JRM Financials Ltd | Financial services | 2026 |
| JS2D Ltd | Wholesale & retail | 2023 |
| JSK Construction Group Ltd | Construction | 2023 |
| JSK Tree Services Ltd | Agriculture & fishing | 2024 |
| JSL Commercial Properties Ltd | Real estate | 2024 |