| Jaam Partners Limited | Real estate | 2019 |
| Jaam UP Limited | Real estate | 2022 |
| Jabari Properties Ltd | Construction | 2023 |
| JAC Electronic Limited | Arts & recreation | 2014 |
| Jaccollections Limited | Wholesale & retail | 2026 |
| Jacemison Company Ltd | Health & social care | 2025 |
| Jacknife Films Limited | Arts & recreation | 2017 |
| Jacob's Empire Ltd | Hospitality | 2025 |
| Jade Angel Ltd | Other services | 2016 |
| Jade Nails 86 Ltd | Other services | 2025 |
| JAE Digital Ltd | Professional & scientific | 2023 |
| Jajett Ltd | Transport & logistics | 2020 |
| James Smith WSM Limited | Financial services | 2019 |
| James Windows Limited | Construction | 2020 |
| Jamie Burrows Ltd | Construction | 2016 |
| Jamie Hayman Plumbing Limited | Water & waste | 2015 |
| Jamie Williams Aerials Limited | Professional & scientific | 2008 |
| Jamkie Limited | Information & communication | 2018 |
| Jane Clarke Architectural Services Ltd | Professional & scientific | 2010 |
| Jarrett Digital Ltd | Professional & scientific | 2020 |
| Jasmine Consultancy Services Ltd | Professional & scientific | 2006 |
| Jason Fuller Limited | Construction | 2016 |
| Jasvin Hostels Ltd | Hospitality | 2018 |
| JAY Ramplin Properties Ltd | Real estate | 2025 |
| JAY Sparkle Consultancy Ltd | Education | 2025 |
| Jay's Transport Services Ltd | Transport & logistics | 2025 |
| Jayandmeg Limited | Health & social care | 2016 |
| Jazzy Corondale Ltd | Real estate | 2022 |
| JB Electrical (South West) Limited | Construction | 2020 |
| JB Jones Property Solutions Ltd | Real estate | 2026 |
| JB Websites Limited | Information & communication | 2020 |
| JBL Deliveries & Removals Ltd | Transport & logistics | 2020 |
| JC Juice & Beverage Consulting Limited | Professional & scientific | 2015 |
| JC Mortgage Brokers Ltd | Financial services | 2018 |
| JC Roofing & Building Services (UK) Limited | Construction | 2018 |
| Jcos Defense Limited | Public administration | 2024 |
| JCS Technology Ltd | Professional & scientific | 2015 |
| JD Crandon Building Services Limited | Construction | 2020 |
| JD Print Supplies Ltd | Wholesale & retail | 2018 |
| JDJ Services Limited | Health & social care | 2025 |
| JDM Cars Somerset Ltd | Wholesale & retail | 2026 |
| Jeff Brown Limited | Wholesale & retail | 1978 |
| Jeffries Joinery Limited | Construction | 2004 |
| Jefmedia Limited | Information & communication | 2025 |
| Jejunary 11 Limited | Financial services | 2010 |
| Jellaboc Limited | Financial services | 2022 |
| JEM Controls Ltd | Manufacturing | 2017 |
| Jemma Services Ltd | Education | 2025 |
| Jems Commercial Finance Limited | Financial services | 2017 |
| Jenefer Properties Ltd | Real estate | 2021 |
| Jennys Food 7 Ltd | Hospitality | 2026 |
| Jerk Quzine Limited | Hospitality | 2026 |
| JES Partnership Ltd | Education | 2022 |
| Jesjaz Ltd | Health & social care | 2019 |
| JET Property 1 Ltd | Real estate | 2026 |
| Jetwish Ltd | Arts & recreation | 2025 |
| JG Water Limited | Construction | 2021 |
| Jgtc Ltd | Real estate | 2025 |
| JH Holdings SW Ltd | Financial services | 2025 |
| JHB Consulting (UK) Limited | Hospitality | 2011 |
| JHB Telecommunications Ltd | Wholesale & retail | 2018 |
| JIA Yuan Oriental Foods Ltd | Wholesale & retail | 2024 |
| Jichawok Limited | Hospitality | 2022 |
| JJ Carpets and Flooring Ltd | Construction | 2016 |
| JJ Safety First Ltd | Professional & scientific | 2021 |
| JJK Catering Ltd | Hospitality | 2019 |
| JJP Holdings Group South West Ltd | Financial services | 2015 |
| JJP Real Estate Ltd | Real estate | 2021 |
| JK Speed Line Limited | Transport & logistics | 2025 |
| JK Studio Property Ltd. | Real estate | 2017 |
| JKI Insights Ltd | Education | 2025 |
| JLH Fortune Ltd | Real estate | 2022 |
| JM TPT Training (SW) Ltd | Transport & logistics | 2021 |
| JM Windows WSM Ltd | Construction | 2022 |
| JMH Ventures Limited | Wholesale & retail | 2022 |
| JMJ Trinity Homes Ltd | Real estate | 2026 |
| JMS Books LLP | | 2002 |
| JMS Weston Limited | Manufacturing | 2015 |
| JMT Leisure Ltd | Financial services | 2019 |
| JMW Property Management (SW) Ltd | Real estate | 2024 |
| Jnark Property Ltd | Real estate | 2026 |
| JNE Holding Limited | Administrative & support | 2016 |
| JNS Render Solutions Ltd | Construction | 2025 |
| Joa&Ima Limited | Hospitality | 2023 |
| JOB (Weston) Limited | Professional & scientific | 2019 |
| Jobfiniti Ltd | Administrative & support | 2019 |
| JOE Kelly Motor Repairs Ltd | Professional & scientific | 2026 |
| John Attwood Landscape Services Limited | Administrative & support | 2002 |
| John E Reed Ltd | Construction | 2019 |
| John Henry Ward Ltd | Extraterritorial | 2023 |
| John Hodge Solicitors LLP | | 2023 |
| John Huish Estates Limited | Real estate | 1961 |
| John West Renewables Limited | Administrative & support | 2010 |
| Jolly Roger Entertainment Ltd | Information & communication | 2024 |
| JON Bartlett Limited | Construction | 2015 |
| JON Organ Limited | Professional & scientific | 2014 |
| Jonathan Boulton Partnership Limited | Health & social care | 2016 |
| Jones Footcare Ltd | Health & social care | 2015 |
| Jones Leisure Ltd | Wholesale & retail | 2021 |
| Jones Property Empire Limited | Real estate | 2017 |