| JE Property Improvement Limited | Construction | 2023 |
| Jean Saints Ltd | Professional & scientific | 2025 |
| JEC Imaging Ltd | Health & social care | 2025 |
| Jeff Blades Upholstery Ltd | Other services | 2014 |
| Jefferson Maguire Limited | Administrative & support | 1997 |
| Jeffries & Partners Limited | Real estate | 1996 |
| Jeffries Eyecare Ltd | Health & social care | 2024 |
| Jeffries Lettings Limited | Real estate | 1999 |
| Jelen Properties Limited | Real estate | 2022 |
| JEM Aesthetics Ltd | Administrative & support | 2020 |
| JEM Maintenance (South) Ltd | Construction | 2026 |
| JEM Timber Ltd | Wholesale & retail | 2026 |
| Jenhams Clinic Ltd | Health & social care | 2015 |
| Jenkins & Marina Grove Ltd | Real estate | 2021 |
| Jenkins and Jones Limited | Extraterritorial | 2006 |
| Jensgems Ltd | Other services | 2014 |
| Jent Estates Limited | Construction | 2006 |
| Jeph & Joy Travels Ltd | Transport & logistics | 2025 |
| Jersey Post Global Logistics UK Limited | Transport & logistics | 1999 |
| Jesiah Trading Ltd | Wholesale & retail | 2023 |
| Jespo Ltd | Wholesale & retail | 2018 |
| Jessie Leigh Dance & Cheer Academy Ltd | Arts & recreation | 2020 |
| JET Connect Ltd | Transport & logistics | 2009 |
| Jetdore Services Limited | Hospitality | 2024 |
| Jetmead Limited | Real estate | 1997 |
| JFC Project Services Limited | Professional & scientific | 2019 |
| JFL Interiors Ltd | Construction | 2023 |
| JG Finance Ltd | Professional & scientific | 2021 |
| JG Zebra Consulting Ltd | Professional & scientific | 2016 |
| JGL Leisure Ltd | Arts & recreation | 2010 |
| JGR Family Investments Limited | Financial services | 2021 |
| JH Roofing & Building Ltd | Construction | 2021 |
| JHE Global Ltd | Construction | 2012 |
| Jhxy Limited | Hospitality | 2023 |
| JI Solution Limited | Hospitality | 2025 |
| JIGSAW3D Limited | Financial services | 2014 |
| Jilly Creative Ventures Ltd | Professional & scientific | 2023 |
| JIM Kynvin Ltd | Professional & scientific | 2015 |
| Jimmins Consultancy Limited | Professional & scientific | 2021 |
| Jing Capital Ltd | Transport & logistics | 2020 |
| Jishaseby RGN Ltd | Health & social care | 2018 |
| Jivvo Ltd | Other services | 2021 |
| Jixi Ltd | Real estate | 2015 |
| JJ Landscape Solutions Ltd | Administrative & support | 2025 |
| JJ Locum Services Limited | Other services | 2011 |
| JJ Makeup Ltd | Other services | 2025 |
| JJ Smith Drainage Ltd | Construction | 2023 |
| Jjhc Consulting Ltd | Professional & scientific | 2020 |
| JJL Subs Limited | Hospitality | 2012 |
| Jjmj Ltd | Administrative & support | 2021 |
| JJW Renovations Limited | Construction | 2026 |
| JK Environmental Holdings Limited | Real estate | 2020 |
| JKG Business Ventures Limited | Professional & scientific | 2021 |
| JKG Property Ventures Ltd | Real estate | 2021 |
| JKM Motor Services Limited | Wholesale & retail | 2002 |
| JL Homes Limited | Construction | 2005 |
| JL Properties SPV Limited | Real estate | 2022 |
| JL Roofing & Cladding Services Ltd | Construction | 2023 |
| JL Tattoos Limited | Other services | 2025 |
| JLD Scaffold Services Ltd | Construction | 2020 |
| JLM Mechanical Ltd | Construction | 2023 |
| JLR Properties (Hants) Ltd | Real estate | 2014 |
| JM Fire and Security Ltd | Administrative & support | 2020 |
| JM Inc Limited | Wholesale & retail | 2020 |
| JM Machinery Ltd | Wholesale & retail | 2018 |
| JM Medical Services Ltd | Health & social care | 2024 |
| JM Motor Sales Ltd | Wholesale & retail | 2025 |
| JM Plumbing and GAS Limited | Construction | 2025 |
| JM1 Stylist Ltd | Other services | 2025 |
| JMC Bricklayers Ltd | Construction | 2022 |
| Jmchase and Partners Limited | Administrative & support | 2017 |
| Jmchase Holdings Ltd | Financial services | 2017 |
| Jmcs Enterprises Limited | Construction | 2014 |
| JMD Corporate Services (UK) Limited | Professional & scientific | 2021 |
| Jmio Consultancy Services Limited | Professional & scientific | 2022 |
| JMR Property South Limited | Real estate | 2025 |
| JMS Asset Management Limited | Financial services | 2023 |
| JN Utility Services Ltd | Energy | 2023 |
| JN2 Ltd | Real estate | 2022 |
| JNR & Sons Limited | Health & social care | 2013 |
| JO Venesse Enterprise Limited | Wholesale & retail | 2025 |
| JO York Coaching & Consulting Limited | Professional & scientific | 2024 |
| Jo-Izzy Ltd | Health & social care | 2017 |
| Joanah Godswill Ltd | Health & social care | 2026 |
| Jobah Limited | Hospitality | 2019 |
| Jobsinrecruitment Ltd | Administrative & support | 2025 |
| Jocelyn Court Management Company Limited | Households | 1992 |
| Joda Investments Ltd | Financial services | 2024 |
| John Crop Development International Limited | Agriculture & fishing | 2020 |
| John Hood Yoga Writing and Commerce Ltd | Hospitality | 2017 |
| John L Holden Consulting Ltd | Professional & scientific | 2015 |
| John Lewis Quay Management Company Limited | Households | 1998 |
| John Pierson (Specialist Maintenance) Limited | Construction | 1995 |
| John Pounds' Community Trust Ltd | Education | 2003 |
| John Wall & SON Pleasure Fairs Limited | Arts & recreation | 2003 |
| Johnnybenny Emporium Services Limited | Wholesale & retail | 2023 |
| Johns Civil Engineering Ltd | Construction | 2017 |
| Johnson's Property Maintenance Limited | Construction | 2010 |
| Joinvoid Limited | Wholesale & retail | 2026 |
| Joke IT Ltd | Wholesale & retail | 2026 |