| Janecki PM Ltd | Construction | 2021 |
| Janet Wilkinson & Associates Limited | Professional & scientific | 2014 |
| Janjua and Associates Limited | Other services | 2007 |
| Janjua Chambers UK Ltd | Information & communication | 2024 |
| Janjua Property Management Limited | Real estate | 2020 |
| JAO Services Limited | Construction | 2023 |
| Jarabosky UK Limited | Manufacturing | 1987 |
| Jarez Brown Property Limited | Real estate | 2025 |
| Jarniamh Holdings Limited | Financial services | 2020 |
| Jarvid Ltd | Wholesale & retail | 2026 |
| Jason Williams Photography Ltd | Professional & scientific | 2026 |
| Jasper Construction Services Limited | Construction | 2017 |
| JAT Clothing Limited | Wholesale & retail | 2007 |
| JAW & TOD Media Limited | Information & communication | 2025 |
| JAY Byrne Limited | Other services | 2013 |
| Jazz Affordable Houses Ltd | Real estate | 2025 |
| Jazz IT UP Marketing Ltd | Information & communication | 2015 |
| JB & MNS Limited | Health & social care | 2026 |
| JB Inns (HX) Ltd | Hospitality | 2026 |
| JBG Holdings Limited | Professional & scientific | 2009 |
| JBG Investment Limited | Real estate | 2020 |
| JBR Gynaecology Limited | Professional & scientific | 2017 |
| JBS Building and Property Services Ltd | Construction | 2021 |
| JBS Jetset Ltd | Administrative & support | 2025 |
| Jbullock Ltd | Hospitality | 2021 |
| JBZ Estates Ltd | Real estate | 2024 |
| JC Goods PVT Ltd | Wholesale & retail | 2025 |
| JC Logic Limited | Wholesale & retail | 2022 |
| JCA Limited | Administrative & support | 2003 |
| JCM Joinery & Building Ltd | Construction | 2023 |
| Jcred Ltd | Construction | 2025 |
| JDB Contracting Ltd | Construction | 2025 |
| JDJ Enterprises LLP | | 2016 |
| Jdmb Ltd | Arts & recreation | 2020 |
| JDP Coaching Ltd | Other services | 2022 |
| JDS Marketing Ltd | Professional & scientific | 2025 |
| JDS Tiling Ltd | Construction | 2024 |
| Jdsd Business Services Limited | Administrative & support | 2024 |
| Jecks Holdings Ltd | Professional & scientific | 2026 |
| JEE Properties & Rentals Limited | Real estate | 2024 |
| JEE Scaffold Towers Ltd | Wholesale & retail | 2016 |
| Jeff's Management Services Limited | Professional & scientific | 2013 |
| Jeffs Property Holdings Limited | Real estate | 2025 |
| JEL Barbers Limited | Other services | 2020 |
| JEM Brickworks Ltd | Construction | 2005 |
| Jenna JAY Hurles Art Ltd | Arts & recreation | 2023 |
| Jennifer Taylor Hairdressing (Brighouse) Ltd | Other services | 2022 |
| Jenny Home Limited | Wholesale & retail | 2025 |
| JEP Contracts Limited | Professional & scientific | 2013 |
| Jessica Summers Hypnogenics Ltd | Education | 2021 |
| JET Media Ltd | Information & communication | 2023 |
| JET Power & Light Commercial Ltd | Construction | 2023 |
| JET Power & Light Ltd | Construction | 2022 |
| JET Renewables Limited | Energy | 2009 |
| JET17 Limited | Real estate | 2021 |
| Jetsoft Digital Ltd | Information & communication | 2025 |
| Jevra Ltd | Wholesale & retail | 2025 |
| Jewells of Halifax Limited | Other services | 2015 |
| JFA Traffic Solutions Ltd | Professional & scientific | 2024 |
| Jfdi Developments Limited | Construction | 2014 |
| JFZ Holdings Limited | Financial services | 2024 |
| JFZ Properties Ltd | Real estate | 2026 |
| JGM GAS Services Ltd | Construction | 2024 |
| Jgreenwood(Holdings) Ltd | Financial services | 2025 |
| JH & SP Products Limited | Wholesale & retail | 2017 |
| JH Electrical (Halifax) Ltd | Construction | 2026 |
| JH Furniture Ltd | Wholesale & retail | 2021 |
| JH Plant & Fleet Consultancy Ltd | Construction | 2024 |
| JH Solar Installation Ltd | Construction | 2022 |
| Jhmp Warley Limited | Wholesale & retail | 2015 |
| JI Commercial Solutions Ltd | Professional & scientific | 2018 |
| Jibby Rescue & Recovery Ltd | Wholesale & retail | 2026 |
| Jiffy Cart Limited | Wholesale & retail | 2025 |
| Jimmy's Gym Limited | Wholesale & retail | 2021 |
| Jimnastiks Ltd | Arts & recreation | 2022 |
| Jimpac UK Ltd | Wholesale & retail | 2026 |
| Jimpex U.K. Packaging Ltd. | Wholesale & retail | 2001 |
| Jingles ALL the Way Community Interest Company | Health & social care | 2025 |
| Jive Nation Entertainment Ltd | Arts & recreation | 2026 |
| JJ Apex Properties Ltd | Real estate | 2019 |
| JJ Empire Holding Limited | Real estate | 2019 |
| JJ Simpkin Joinery Limited | Construction | 2025 |
| Jjhu Properties Ltd | Real estate | 2024 |
| JJM Telecoms Ltd | Information & communication | 2017 |
| Jjmc Electrical Ltd | Construction | 2023 |
| Jjml Media Limited | Information & communication | 2026 |
| JJR Logistics Limited | Transport & logistics | 2020 |
| JJT Belcher Limited | Professional & scientific | 2022 |
| Jjtar Ltd | Professional & scientific | 2017 |
| JK Leasing Ltd | Financial services | 2019 |
| JK Property & Renovations Ltd | Real estate | 2022 |
| JKG Property Developments Limited | Real estate | 2021 |
| JKM Engineering Ltd | Manufacturing | 2018 |
| JL (Holdings) Ltd | Financial services | 2014 |
| JL7 Ltd | Professional & scientific | 2025 |
| JLB Specialist Vehicles Limited | Construction | 2009 |
| JLD Brickwork Ltd | Construction | 2022 |
| JLG Scanning Ltd | Health & social care | 2024 |
| JLN Homes Ltd | Real estate | 2025 |
| JLT Garratt Ltd | Real estate | 2024 |