| JM Surveying Ltd | Professional & scientific | 2024 |
| JM UK Property Ltd | Real estate | 2024 |
| JMB Hardware Ltd | Wholesale & retail | 2024 |
| JMB Landscaping Ltd | Administrative & support | 2023 |
| JMD Tools and Equipment Limited | Administrative & support | 2025 |
| JMS Resources Limited | Professional & scientific | 2009 |
| JMW Holdings Group Limited | Wholesale & retail | 2025 |
| JN Fire and Security Solutions Ltd | Administrative & support | 2019 |
| JND Projects Limited | Construction | 2011 |
| JNH Commercial Services Limited | Professional & scientific | 2017 |
| JNH Electrical Limited | Energy | 2019 |
| JNH Logistics Ltd | Transport & logistics | 2025 |
| JNP Commercials Ltd | Real estate | 2019 |
| JO JO Child Care Limited | Health & social care | 2020 |
| JO Whitehead ACP Limited | Health & social care | 2020 |
| Joandric Consultancy Limited | Financial services | 2010 |
| JOB Reporting Ltd | Health & social care | 2017 |
| Jodd Investments Limited | Real estate | 2024 |
| JOE Webb Carpets Limited | Wholesale & retail | 2016 |
| Joel O Group Limited | Administrative & support | 2024 |
| Joel O Ltd | Administrative & support | 2018 |
| Joetie Home Ltd | Wholesale & retail | 2022 |
| John Everiss Design Limited | Administrative & support | 2001 |
| John Frankie Grainger T/As Malt and Hops Limited | Hospitality | 2017 |
| John Goulding & Co. Limited | Extraterritorial | 2017 |
| John Prescott Maintenance Limited | Construction | 2011 |
| John Smith & Sons(Chorley)Limited | Agriculture & fishing | 1964 |
| John Turnbull Limited | Transport & logistics | 2012 |
| Johnson Care Group Ltd | Extraterritorial | 2023 |
| Johnson Family Ltd | Real estate | 2025 |
| Johnson’S Automoves Ltd | Transport & logistics | 2024 |
| Joker Limited | Arts & recreation | 2003 |
| Jolly Purvis Pubs Ltd | Hospitality | 2024 |
| Jolsa Curry House Limited | Hospitality | 2025 |
| Jolsa Food Ltd | Hospitality | 2022 |
| JON Corden Consulting Ltd | Administrative & support | 2015 |
| JON Ryley Limited | Information & communication | 2025 |
| Joner Transport Ltd | Transport & logistics | 2013 |
| Jones Civils & Groundworks Ltd | Construction | 2019 |
| Jonikrik Investments Limited | Financial services | 2025 |
| Jonise Ltd | Hospitality | 2024 |
| Jonny Cocktail Bars Limited | Hospitality | 2024 |
| Jonny Cocktail Events Limited | Hospitality | 2011 |
| Joro Property Ltd | Real estate | 2020 |
| Joro Restaurant Limited | Hospitality | 2016 |
| Jortec Solutions Ltd | Wholesale & retail | 2025 |
| Journey Financial Planning Ltd | Financial services | 2024 |
| Joyner Estate Limited | Professional & scientific | 2015 |
| Joynur Travel Ltd | Administrative & support | 2019 |
| JP Clinical Services Limited | Health & social care | 2021 |
| JPD Homes Limited | Real estate | 2018 |
| JPD Piling & Groundwork Limited | Construction | 2016 |
| JPF Enterprises (NW) Ltd | Education | 2026 |
| JPM Building & Joinery Services Limited | Construction | 2021 |
| JPM Business Services Limited | Professional & scientific | 2024 |
| JPM Signalling Limited | Administrative & support | 2018 |
| JPS Gaming and Leisure Limited | Administrative & support | 2023 |
| JQ Plumbing and Heating Limited | Construction | 2024 |
| JQ Property and Rentals Limited | Real estate | 2024 |
| JR Elite Home Improvement Ltd | Construction | 2024 |
| JR Setting OUT Limited | Construction | 2010 |
| JR Wheels Limited | Wholesale & retail | 2014 |
| Jrar Ltd | Other services | 2025 |
| JRM Decorators Limited | Construction | 2014 |
| JRN Aggregates Ltd | Transport & logistics | 2025 |
| JRS Commercial Estates Ltd | Real estate | 2025 |
| JRT Wealth Management Limited | Extraterritorial | 2011 |
| JS Auto Tuning and Performance Limited | Wholesale & retail | 2018 |
| JS Autocare Limited | Wholesale & retail | 2018 |
| Jsac Ltd | Real estate | 2015 |
| Jsav UK Ltd | Professional & scientific | 2010 |
| JSL Resourcing Limited | Energy | 2018 |
| JST Group Ltd | Financial services | 2018 |
| Jtdistrubutions Ltd | Wholesale & retail | 2025 |
| JTK Propco Limited | Real estate | 2024 |
| JUA Group Ltd | Wholesale & retail | 2025 |
| Jubilee Computer Services Ltd | Wholesale & retail | 2016 |
| Julessave Ltd | Transport & logistics | 2024 |
| JULIA15 Ltd | Transport & logistics | 2017 |
| Julie Guilliatt Limited | Hospitality | 2018 |
| Jumpin Sussex Ltd | Arts & recreation | 2018 |
| Jumpstart International Limited | Wholesale & retail | 2019 |
| Jupiter Group NW Ltd | Real estate | 2002 |
| Just Construction Networking Limited | Professional & scientific | 2013 |
| Just Giorge Ltd | Information & communication | 2021 |
| Just Innovate Ltd | Professional & scientific | 2024 |
| Just Trans Ltd | Transport & logistics | 2021 |
| JVB Engineering Services Ltd | Professional & scientific | 2021 |
| JVH Traditional AGA Cooker Services Ltd | Manufacturing | 2022 |
| JVW Heating Ltd | Construction | 2013 |
| JW Business Investments Limited | Real estate | 2018 |
| JW56 Ltd | Professional & scientific | 2024 |
| Jws.Services Traffic Management Limited | Transport & logistics | 2013 |
| Jzarr Ltd | Wholesale & retail | 2025 |
| JZK UK Ltd | Real estate | 2023 |
| K & a Residential Developments Limited | Real estate | 2026 |
| K Bellamy Transport Limited | Transport & logistics | 2018 |
| K Berry Limited | Construction | 2007 |
| K H Drive Ltd | Real estate | 2026 |
| K Kinloch Consulting Ltd | Professional & scientific | 2026 |