| J. P. Property Consultants Ltd | Real estate | 2010 |
| J. T. Adams (Springs) Limited | Manufacturing | 1982 |
| J.B. Sands Limited | Agriculture & fishing | 1976 |
| J.Dunne Construction Limited | Construction | 2015 |
| J.E.M Automotive Ltd | Wholesale & retail | 2024 |
| J.R. Engineering (Presses) Limited | Manufacturing | 1998 |
| J.R.Bradshaw Limited | Professional & scientific | 2025 |
| J.W. Sherratt (Builders) Ltd | Construction | 2005 |
| J.W.E. Williams Limited | Professional & scientific | 2013 |
| J18 Projects Limited | Professional & scientific | 2015 |
| J3R Consulting Limited | Professional & scientific | 2020 |
| JAB Painters & Decorators Ltd | Construction | 2025 |
| Jabali MEN Network CIC | Public administration | 2023 |
| Jacell Construction Ltd | Construction | 2026 |
| Jack Greenwood Construction Ltd | Construction | 2019 |
| Jackalope's ALL American Ltd | Hospitality | 2015 |
| Jackson Perry Legal Services Limited | Professional & scientific | 2012 |
| Jackson Tilbury Property Ltd | Real estate | 2022 |
| Jackson-Holmes Consulting Ltd | Professional & scientific | 2025 |
| Jacybuy Ltd | Wholesale & retail | 2022 |
| Jaesops Dungeon Ltd | Wholesale & retail | 2024 |
| Jagtar Larysa Mahal Limited | Real estate | 2023 |
| Jaguar Cricket Ltd | Education | 2022 |
| Jahflava's CIC | Hospitality | 2025 |
| Jahflava's Restaurant Ltd | Hospitality | 2025 |
| Jaju Property Limited | Real estate | 2025 |
| JAK Installations Limited | Construction | 2013 |
| Jalp London Ltd | Professional & scientific | 2014 |
| James and Ward Limited | Professional & scientific | 2006 |
| James Hunt Building Services Limited | Construction | 2011 |
| James Mcgrath Inns Ltd | Hospitality | 2020 |
| James Metal Design and Fabrication Limited | Manufacturing | 2018 |
| Janus Events Limited | Hospitality | 2015 |
| Japan Dayunco Co., Ltd | Extraterritorial | 2021 |
| Japan Longyehuacheng Zhushehuishe Limited | Mining & quarrying | 2025 |
| Japhlin Computer Services Ltd | Other services | 2021 |
| Jase Macs Woodshack Ltd | Manufacturing | 2025 |
| Jason Holland (Properties) Limited | Hospitality | 2006 |
| Jaspers the Bakers Limited | Manufacturing | 2020 |
| Jaswant Maan Ltd | Real estate | 2023 |
| Jaymand Ltd | Health & social care | 2021 |
| Jayne Packham Consultancy Ltd | Administrative & support | 2006 |
| Jayne Packham Holdings Limited | Financial services | 2022 |
| JB PPC Limited | Professional & scientific | 2023 |
| JB3DPRINTS LLP | | 2026 |
| JBB Telecoms Ltd | Administrative & support | 2016 |
| JC Stroke Care Ltd | Health & social care | 2024 |
| JC Triathlon Ltd | Arts & recreation | 2025 |
| Jc&Ms Delivery Ltd | Transport & logistics | 2025 |
| JCT Trading and Management Ltd | Wholesale & retail | 2020 |
| JD Dodd Ltd | Hospitality | 2019 |
| JD Green Trading Ltd | Wholesale & retail | 2025 |
| JDC First Ltd | Transport & logistics | 2017 |
| JDC Investments (USA) Ltd | Arts & recreation | 2011 |
| JDC Investments Limited | Administrative & support | 2011 |
| Jdsb Engineering Limited | Wholesale & retail | 2023 |
| JEB Wealth Management Limited | Financial services | 2022 |
| JEF Services Ltd | Professional & scientific | 2025 |
| Jenkins Investing Limited | Real estate | 2023 |
| Jenkins Investments Holdings Limited | Financial services | 2023 |
| Jenkinsons Holdings (Stafford) Limited | Financial services | 1953 |
| Jenn & Brett Travel Limited | Administrative & support | 2024 |
| Jeremy Barth Ltd | Wholesale & retail | 2025 |
| Jerona Care Services Limited | Health & social care | 2012 |
| JES Electrical Ltd | Construction | 2006 |
| Jessantanp Ltd | Health & social care | 2022 |
| Jetset Johnnie Limited | Other services | 2014 |
| Jewelstaff Limited | Professional & scientific | 2001 |
| Jeyananda Enterprises Limited | Wholesale & retail | 2018 |
| Jeyananda Retail Limited | Wholesale & retail | 2023 |
| Jfdi Group Ltd | Hospitality | 2025 |
| JG Auto Doors Ltd | Manufacturing | 2024 |
| JH Damp Solutions Ltd | Construction | 2026 |
| JH Incorporated Ltd | Construction | 2024 |
| JH Plastering Solutions Ltd | Construction | 2026 |
| JHM Invest Ltd | Information & communication | 2022 |
| Ji-Reh Management & Promotions Limited | Arts & recreation | 2022 |
| Ji-Reh Resettlement Service Ltd | Administrative & support | 2012 |
| Jiahe Global Ltd | Wholesale & retail | 2025 |
| Jiajin Limited | Hospitality | 2018 |
| Jiakechongbl Co., Ltd | Wholesale & retail | 2024 |
| Jiangbei Additive Co., Ltd | Wholesale & retail | 2021 |
| Jiangsu Cunrui Metal Products Co., Ltd | Extraterritorial | 2016 |
| Jiangxin Trade Ltd | Wholesale & retail | 2025 |
| Jianhua Trade Co., Ltd | Wholesale & retail | 2023 |
| Jiaxing Changken Import and Export Co., Ltd | Extraterritorial | 2019 |
| Jiaxun Ltd | Extraterritorial | 2022 |
| Jibjab Properties Ltd | Real estate | 2024 |
| Jibofet Solutions Limited | Wholesale & retail | 2025 |
| Jigsaw Removal Group Ltd | Transport & logistics | 2021 |
| JIH Holdings Limited | Financial services | 2024 |
| JIN Chuang UK Ltd | Manufacturing | 2025 |
| JIN Deng Limited | Hospitality | 2023 |
| JIN HUA HUO LAN Trading Co., Limited | Wholesale & retail | 2025 |
| Jinbei Trading Group Ltd | Wholesale & retail | 2025 |
| Jincheng Steel Limited | Manufacturing | 2023 |
| Jinhua Paper Mall Company Limited | Wholesale & retail | 2022 |
| Jinpu Import and Export Co., Ltd | Wholesale & retail | 2023 |
| Jinran Limited | Wholesale & retail | 2025 |
| Jinrui Intermational Trading Company., Ltd | Wholesale & retail | 2025 |