| JJM Resources Limited | Professional & scientific | 2014 |
| JJM Vehicle Management Ltd | Wholesale & retail | 2015 |
| Jjnp Consulting Limited | Information & communication | 2006 |
| Jjordan Properties Limited | Real estate | 2026 |
| JJS Residential Limited | Real estate | 2026 |
| JK Bulk Services Ltd | Agriculture & fishing | 2025 |
| JKA Consultancy Ltd | Professional & scientific | 2022 |
| JKM Automatics Ltd | Wholesale & retail | 2025 |
| JL Homes (N/W) Ltd | Real estate | 2024 |
| JL1 Housing Limited | Construction | 2024 |
| Jlam Poulton Ltd | Real estate | 2017 |
| JLB Property (Atlas House) Ltd | Construction | 2025 |
| Jleaf Limited | Wholesale & retail | 2011 |
| Jleag Solar 1 Limited | Energy | 2015 |
| JLT Homes Ltd | Real estate | 2018 |
| JM Connections Limited | Administrative & support | 1998 |
| JM Hairstyling Ltd | Other services | 2025 |
| JM Jones Holdings Ltd | Financial services | 2025 |
| JM Partners UK Limited | Information & communication | 2009 |
| Jmac Civil Engineering Limited | Professional & scientific | 2008 |
| Jmarch Limited | Agriculture & fishing | 2017 |
| JMB Assets Limited | Real estate | 2021 |
| JMB Maintenance Services Ltd | Construction | 2023 |
| Jmcp Developments Limited | Construction | 2026 |
| Jmdb Software Limited | Extraterritorial | 2012 |
| Jmellons Limited | Construction | 2022 |
| JMH Bridge Engineers Limited | Professional & scientific | 2008 |
| JMK Construction Consultants Ltd | Construction | 2024 |
| JMK Construction Group Ltd | Financial services | 2025 |
| JMK Developments Ltd | Construction | 2025 |
| JML Consulting Limited | Wholesale & retail | 2003 |
| JMM Resourcing Limited | Administrative & support | 2022 |
| JMP Commercial Services Limited | Wholesale & retail | 2007 |
| JMS Legal Ltd | Professional & scientific | 2023 |
| JN Events Ltd | Arts & recreation | 2025 |
| JNR Chef Ltd | Hospitality | 2022 |
| JNR Construction Ltd | Construction | 2011 |
| Joanna Jones Consulting Ltd | Professional & scientific | 2026 |
| Joanne Cairns Limited | Professional & scientific | 2019 |
| Jobsinn Ltd | Administrative & support | 2021 |
| Joby Ltd | Professional & scientific | 2023 |
| JOG Highlands LLP | | 2010 |
| John Brown Builders Limited | Construction | 1993 |
| John Cook (Corn Merchants) Limited | Wholesale & retail | 1951 |
| John Froehlich Limited | Construction | 2021 |
| John Howe Limited | Water & waste | 2022 |
| John Nicol Ltd | Professional & scientific | 2003 |
| John O'Groats Highlands Limited | Hospitality | 2011 |
| John Potts (Electrical Contractors) Limited | Construction | 2000 |
| John S Brown and SON Limited | Real estate | 1997 |
| John Taylor Cheshire Limited | Administrative & support | 2005 |
| John Thorley Safety Consultancy Limited | Professional & scientific | 2014 |
| John Worth Limited | Construction | 1964 |
| Joistwheel Limited | Real estate | 1991 |
| Jola Designs Ltd | Manufacturing | 2016 |
| Jolly Sailor Macc Ltd | Hospitality | 2025 |
| Jome Construction Ltd | Construction | 2018 |
| Jones & Jones Design Consultants Ltd | Professional & scientific | 2019 |
| Jones Associates (North West) Limited | Households | 2011 |
| Jones Associates Block Management Limited | Households | 2011 |
| Jones Associates Chestergate Limited | Households | 2024 |
| Jones Associates Group Limited | Extraterritorial | 2025 |
| Jones Associates Retirement Company Limited | Households | 2015 |
| Jones Knowles Warburton Limited | Professional & scientific | 2004 |
| Jones the Chocolate Maker Ltd | Wholesale & retail | 2025 |
| Jonick Developments Limited | Construction | 2023 |
| Jonick East Developments Ltd | Construction | 2024 |
| Jonick Property Investments Ltd | Real estate | 2024 |
| Jonick South Holdings Limited | Construction | 2023 |
| Jonny Wilson Photography Ltd | Professional & scientific | 2023 |
| Jordan and Holland Properties Limited | Real estate | 2020 |
| Jordan Fishwick (Financial Services) Limited | Financial services | 1995 |
| Jordan Fishwick (Manchester) Ltd | Real estate | 2012 |
| Jordan Fishwick LLP | | 2004 |
| Jordan Fishwick West Limited | Real estate | 2000 |
| Jordan Gregory Limited | Health & social care | 2014 |
| Jordan Investment Holdings Ltd | Real estate | 2020 |
| Jordangate Property Investment Limited | Real estate | 2015 |
| Jore Property Limited | Real estate | 2025 |
| Joseph Torr Limited | Agriculture & fishing | 1961 |
| Joseph's Restaurants Ltd | Hospitality | 2008 |
| Josh Peers Consultancy Ltd | Professional & scientific | 2020 |
| Josolyne Holdings Limited | Financial services | 1987 |
| Josolyne LLP | | 2020 |
| Josolyne Medical Services Ltd | Professional & scientific | 2010 |
| JP Industrial Hygiene Limited | Professional & scientific | 2026 |
| JP Property Development & Services Ltd | Manufacturing | 2022 |
| JPB Financial Planning Limited | Financial services | 2015 |
| Jphr Services Ltd | Administrative & support | 2015 |
| JPI 1 Ltd | Real estate | 2015 |
| JPN Gardens Ltd | Administrative & support | 2026 |
| JPS Project Managment Ltd | Extraterritorial | 2024 |
| JPS Vending Ltd | Wholesale & retail | 2025 |
| JR Concepts Limited | Professional & scientific | 2013 |
| JR Sports Massage Limited | Other services | 2021 |
| JRN Associates Ltd | Real estate | 2021 |
| JS Cubed Consultancy Ltd | Professional & scientific | 2026 |
| JS3ACTIVE Ltd | Arts & recreation | 2025 |
| JSE Property Group (Marthall) Limited | Construction | 2026 |
| JSP Elite Management Ltd | Real estate | 2025 |