| Jessica Summers Projects Limited | Education | 2019 |
| Jessica Yarnold Design Ltd | Professional & scientific | 2020 |
| Jesus College (Harston Barns) Limited | Construction | 2019 |
| Jesus College (Station Road Investments) Limited | Real estate | 2008 |
| Jesus College Cambridge Conferences Limited | Other services | 1993 |
| Jesus College Cambridge Properties Limited | Extraterritorial | 1993 |
| Jesus College Developments Limited | Construction | 1998 |
| Jesusmyprovider IS NOT Ltd | Administrative & support | 2015 |
| JET Aero Services Ltd | Manufacturing | 2023 |
| JET Exchange Limited | Transport & logistics | 2007 |
| JET Exchange Management Ltd | Transport & logistics | 2016 |
| Jetafx Limited | Extraterritorial | 2025 |
| Jetcambs Ltd | Information & communication | 2020 |
| Jetoni CS Ltd | Construction | 2024 |
| Jewish Voice Ministries UK | Other services | 2007 |
| Jfcreative Ltd | Information & communication | 2026 |
| Jfdi Pizza Ltd | Hospitality | 2025 |
| JFK Consultancy Ltd | Professional & scientific | 2021 |
| JGR Example Limited | Other services | 2024 |
| Jgsbiopharma Limited | Professional & scientific | 2013 |
| JGT Healthcare Ltd | Health & social care | 2025 |
| JH Composites Ltd | Manufacturing | 2017 |
| Jhaf Holdings Ltd | Financial services | 2026 |
| JHB Roofing Ltd | Construction | 2025 |
| Jhcox Motor Engineers Ltd | Wholesale & retail | 2012 |
| JHL International Group Co., Ltd | Wholesale & retail | 2021 |
| Jhonny Flyers Ltd | Manufacturing | 2024 |
| JI BAO (China) Investment Company Limited | Wholesale & retail | 2023 |
| JI Kitchen Ltd | Hospitality | 2025 |
| JIA HE IMP and EXP Trading Co., Limited | Wholesale & retail | 2023 |
| Jiaerwei Ltd | Manufacturing | 2025 |
| Jiamart Tech Limited | Wholesale & retail | 2019 |
| Jiamart Trading Limited | Wholesale & retail | 2019 |
| Jianer Kang Co., Limited | Wholesale & retail | 2024 |
| Jianfeng Consulting Limited | Information & communication | 2016 |
| Jiang SU Baicheng Textile Co., Ltd | Extraterritorial | 2015 |
| Jiang XI Hongchen Company Limited | Professional & scientific | 2021 |
| Jianglang Limited | Hospitality | 2019 |
| Jiangshan Maoyi Shipping Service Co., Ltd | Wholesale & retail | 2023 |
| Jiangsu Aoxin New Energy Automobile Co., Ltd. | Manufacturing | 2017 |
| Jiangsu Yaslen Enviromental Protection Co., Ltd. | Extraterritorial | 2023 |
| Jiaxi International Co., Limited | Manufacturing | 2022 |
| Jiayang Industry Co., Ltd | Manufacturing | 2019 |
| Jiayi Trading Co., Ltd | Wholesale & retail | 2024 |
| Jieli Filter Automotive Co., Ltd | Extraterritorial | 2013 |
| Jihudianzishangmao Limited | Wholesale & retail | 2025 |
| Jill Campion Handmade Tile Limited | Manufacturing | 1992 |
| JIM Marsh Properties Ltd | Households | 2023 |
| Jim's Composites Limited | Manufacturing | 2015 |
| Jimjams Limited | Wholesale & retail | 2000 |
| Jimmy Care Limited | Health & social care | 2017 |
| Jimmy Composites Ltd | Manufacturing | 2025 |
| Jimmy's Cambridge | Hospitality | 1996 |
| JIN Qiao International Group Holding Co., Ltd | Extraterritorial | 2012 |
| Jinan Sinoheng Import and Export Co., Ltd | Wholesale & retail | 2024 |
| Jincheng Import and Export Trading Co., Ltd | Wholesale & retail | 2021 |
| Jinggong Watch Co., Ltd | Wholesale & retail | 2024 |
| Jingle Fast Group Co., Ltd. | Extraterritorial | 2023 |
| Jingma Ltd | Agriculture & fishing | 2026 |
| Jingyuan Furniture Co., Ltd | Wholesale & retail | 2023 |
| Jingzun Sanitary Ware Co., Ltd. | Extraterritorial | 2014 |
| Jinhua Hengchuang New Energy Co., Ltd | Wholesale & retail | 2024 |
| Jinming Ltd | Information & communication | 2024 |
| Jinqi Solar Co., Ltd | Wholesale & retail | 2025 |
| Jioptics Technology Co., Ltd | Manufacturing | 2025 |
| Jitri UK Limited | Professional & scientific | 2024 |
| Jiumi Ltd | Administrative & support | 2025 |
| JIVA360 Photobooth Ltd | Professional & scientific | 2025 |
| JJ Hefferon Civils Limited | Administrative & support | 2016 |
| JJ Medics Ltd | Health & social care | 2025 |
| JJ Roofing Solutions Limited | Construction | 2023 |
| JJ Scientific Consultant Ltd | Extraterritorial | 2012 |
| JJR Services (UK) Limited | Construction | 2014 |
| JK 724 Security Services Ltd | Administrative & support | 2022 |
| JK Carbon Painters Ltd | Manufacturing | 2022 |
| JK Firms Ltd | Construction | 2024 |
| JK Global Sales Limited | Wholesale & retail | 2024 |
| JKO Composites Ltd | Manufacturing | 2023 |
| JKS RAD Limited | Health & social care | 2022 |
| JL Painting Solutions Ltd | Construction | 2014 |
| JLH Enterprises Limited | Administrative & support | 1985 |
| JLK Advisory Limited | Professional & scientific | 2025 |
| JLP Cleaning Services Limited | Administrative & support | 2025 |
| JLR Electrical Ltd | Construction | 2020 |
| JLS Mortgages Limited | Financial services | 2006 |
| JLX Cleaning Services Ltd | Administrative & support | 2026 |
| JM Aircraft Maintenance & Training Services Ltd | Manufacturing | 2026 |
| JM Aviation Solutions Ltd | Professional & scientific | 2025 |
| JM Construction (Cambridge) Limited | Construction | 2019 |
| JM Events Ltd | Arts & recreation | 2021 |
| JM Global Group DIV1 Ltd | Real estate | 2025 |
| JM Global Group DIV2 Ltd | Real estate | 2025 |
| JM Global Group DIV3 Ltd | Construction | 2026 |
| JM Global Group Ltd | Financial services | 2025 |
| JM Global Ltd | Construction | 2023 |
| JM Hyde Limited | Real estate | 2019 |
| JM Properties & Management Ltd | Households | 2019 |
| JM Transport Consulting Ltd | Transport & logistics | 2023 |
| JM Union INT Co., Ltd | Extraterritorial | 2024 |
| JMB Cleaning Services Ltd | Administrative & support | 2021 |