| JK Electrical Engineering Ltd | Professional & scientific | 2018 |
| JK Fryers Ltd | Hospitality | 2025 |
| JKJ Associates Ltd | Real estate | 2021 |
| JKM Law Ltd | Professional & scientific | 2024 |
| JKV Real Estate Ltd | Real estate | 2024 |
| JL20 Restaurants Ltd | Hospitality | 2020 |
| JM Cost Consulting Ltd | Administrative & support | 2025 |
| JM Miller Ltd | Other services | 2017 |
| JM Tracks Ltd | Construction | 2018 |
| Jmac Audio Limited | Professional & scientific | 2019 |
| JMB 5820 Ltd | Hospitality | 2024 |
| JMC Lifts Ltd | Manufacturing | 2020 |
| JMC Rigging Ltd | Construction | 2026 |
| Jmcc Limited | Real estate | 2018 |
| Jmccb Ltd | Hospitality | 2018 |
| Jmcd Legal Limited | Professional & scientific | 2015 |
| Jmct Ltd | Wholesale & retail | 2018 |
| Jmdee Ltd | Professional & scientific | 2014 |
| Jmilev Ltd | Construction | 2013 |
| JMJ Catering Solutions Ltd | Hospitality | 2024 |
| JMJ Electronics Ltd | Wholesale & retail | 2024 |
| JMJ Projects Limited | Construction | 2010 |
| JMJ Surrey Ltd | Wholesale & retail | 2017 |
| JMW Services Ltd | Other services | 2019 |
| JMW Turfcare Limited | Other services | 2015 |
| JN Construction Services Ltd | Construction | 2019 |
| JNK Technologies Ltd | Health & social care | 2015 |
| Jntk Consulting Ltd | Professional & scientific | 2026 |
| Joab Properties Ltd | Real estate | 2016 |
| Joanna Shepard Conservation Ltd | Professional & scientific | 2022 |
| Jobsathos Ltd | Administrative & support | 2024 |
| JOE Davey Restoration Ltd | Construction | 2023 |
| JOE Sushi Limited | Hospitality | 2023 |
| Joel Francis Ltd. | Real estate | 2012 |
| Joepc Consulting Ltd | Information & communication | 2022 |
| John Bevans Services Ltd | Construction | 2012 |
| John Fraser Jenkins Limited | Other services | 2003 |
| John K Harris Associates Limited | Professional & scientific | 2011 |
| John's Court (Sutton) Management Company Limited | Households | 2016 |
| Johnden Limited | Information & communication | 1993 |
| Johnie's Limited | Hospitality | 2023 |
| Joiner Investments Limited | Administrative & support | 1972 |
| Joiner Properties Ltd | Real estate | 2017 |
| Jolly Cook Ltd | Hospitality | 2011 |
| Jomi Consultancy Limited | Health & social care | 2012 |
| Jonathan Cummins Ltd | Real estate | 2024 |
| Jonbo Ltd | Professional & scientific | 2026 |
| Jorus UK Ltd | Real estate | 2026 |
| Jose Garden Services Ltd | Other services | 2015 |
| Joseon Ltd | Administrative & support | 2021 |
| Josh Patrick Electrical Services Ltd | Construction | 2025 |
| Joshela Ltd | Real estate | 2025 |
| Journey Star Ltd | Administrative & support | 2012 |
| Joy Kite Properties Limited | Real estate | 2019 |
| Joys Group Management Limited | Real estate | 2026 |
| JP Accounts Ltd | Professional & scientific | 2026 |
| Jpbm Property Ltd | Construction | 2021 |
| JPD Property Holdings Ltd | Real estate | 2023 |
| JPD Systems Accountancy Services Ltd | Information & communication | 2015 |
| JPL Nominees Ltd | Financial services | 2022 |
| Jplumb Ltd | Construction | 2023 |
| JR Cladding and Render Specialist Limited | Administrative & support | 2020 |
| JR Design Ltd | Construction | 2018 |
| Jraz Limited | Wholesale & retail | 2024 |
| JRM Boret Surveyors Limited | Professional & scientific | 2009 |
| Jrnyon Limited | Information & communication | 2023 |
| JS Building & Maintenances Services Limited | Construction | 2018 |
| JS General Construction Ltd | Construction | 2020 |
| JS Investment Properties Ltd | Real estate | 2020 |
| JS Roofers Limited | Construction | 2026 |
| JS4 Properties Ltd | Real estate | 2024 |
| JSB Property Lettings Ltd | Real estate | 2019 |
| JSC Mortgages Ltd | Financial services | 2014 |
| JT Cabling Installation Limited | Construction | 2017 |
| Jtbs Properties Ltd | Households | 2026 |
| JTG Services Ltd | Transport & logistics | 2016 |
| Jtmd Properties Limited | Real estate | 2016 |
| JTT Roofing & Building Services Ltd | Construction | 2019 |
| Jubilant Homes Limited | Real estate | 2022 |
| Julia Crawford Design Ltd | Professional & scientific | 2018 |
| Jungle Nation Film Ltd | Information & communication | 2024 |
| Junior Kids Limited | Wholesale & retail | 1996 |
| Junior Kidz Limited | Wholesale & retail | 2022 |
| Juri London Ltd | Construction | 2016 |
| Just a Crumb Ltd | Hospitality | 2021 |
| Just B Communications Limited | Professional & scientific | 2015 |
| Just JOE Garner Ltd | Wholesale & retail | 2017 |
| Just PR Ltd | Professional & scientific | 2005 |
| Just Store Ltd | Administrative & support | 2025 |
| Justin King Law Ltd | Professional & scientific | 2017 |
| Justrent Ltd | Real estate | 2018 |
| Justyfry Limited | Hospitality | 2017 |
| Justyna Worek Accounting Limited | Professional & scientific | 2024 |
| Jwaneng Holding Ltd | Administrative & support | 2022 |
| JWB Smart Repair Solutions Ltd | Wholesale & retail | 2017 |
| JZ Heights Ltd | Wholesale & retail | 2025 |
| K & B Ceilings Limited | Construction | 2004 |
| K & B Installer Limited | Construction | 2018 |
| K & K Nails Limited | Other services | 2017 |
| K and V Investments Limited | Financial services | 2024 |