| Jeniii Ltd | Wholesale & retail | 2022 |
| Jenkins & Ryan (Steels) Limited | Wholesale & retail | 1978 |
| Jennies Foods Ltd | Hospitality | 2019 |
| Jennifer Chalmers Limited | Arts & recreation | 2016 |
| Jennifer Housen Limited | Professional & scientific | 2022 |
| Jennifer NG Psychotherapy Limited | Health & social care | 2021 |
| Jennifer's at Harborne Ltd | Other services | 2024 |
| Jennings Property Services Limited | Real estate | 2021 |
| Jennock Limited | Wholesale & retail | 2013 |
| Jennsha Ltd | Manufacturing | 2024 |
| Jenny Bailey Investments Limited | Wholesale & retail | 2017 |
| Jenny Foods UK Ltd | Hospitality | 2014 |
| Jenny`S Kitchen (Wall Heath) Limited | Hospitality | 2009 |
| Jens Cafe Limited | Hospitality | 2024 |
| Jens Supported Accommodation UK Ltd | Hospitality | 2026 |
| Jens Universal Limited | Administrative & support | 2023 |
| Jeny UK Service Ltd | Wholesale & retail | 2021 |
| Jeoni Constructions Ltd | Construction | 2024 |
| JEP Entertainment Ltd | Arts & recreation | 2006 |
| Jepa Star Ltd | Hospitality | 2025 |
| Jepcia Global Limited | Other services | 2025 |
| Jeravum Global Workforce Relocations Limited | Hospitality | 2024 |
| Jerberrycoot Consulting Limited | Professional & scientific | 2025 |
| Jerd Ltd | Health & social care | 2020 |
| Jericho Centre | Health & social care | 2007 |
| Jericho Enterprises CIC | Construction | 1998 |
| Jerk Box Limited | Hospitality | 2025 |
| Jerk Centre Street Food Ltd | Hospitality | 2021 |
| Jerk Palace Ltd | Hospitality | 2012 |
| Jerky John Limited | Hospitality | 2022 |
| Jerky John's Caribbean Takeaway Limited | Hospitality | 2023 |
| Jerky Johns Jerk and Dine Ltd | Hospitality | 2025 |
| Jermyn Street Properties Limited | Construction | 1992 |
| Jerog Services Ltd | Health & social care | 2012 |
| Jerome House Ltd | Real estate | 2020 |
| Jerome Trading Limited | Wholesale & retail | 2020 |
| Jerry Gold Ltd | Manufacturing | 2025 |
| Jerry's Pizza Chicken & Burgers Limited | Hospitality | 2025 |
| Jerry's Property Limited | Real estate | 2018 |
| Jerry's Visa Service Limited | Professional & scientific | 2020 |
| Jerrydon Limited | Wholesale & retail | 2011 |
| Jerusha Retail Ltd | Wholesale & retail | 2024 |
| Jervis Capital Limited | Financial services | 2021 |
| Jesq Solutions Limited | Wholesale & retail | 2024 |
| Jessabs Limited | Real estate | 2002 |
| Jesse Driving School Ltd | Transport & logistics | 2014 |
| Jessica Dhariwal Limited | Professional & scientific | 2025 |
| Jessica Duffen Estates Ltd | Real estate | 2023 |
| Jessica's Sweets Cheltenham and Gloucester Limited | Wholesale & retail | 2023 |
| Jessica's Sweets Worcester Limited | Wholesale & retail | 2014 |
| Jessicas Sweets Gloucester Ltd | Wholesale & retail | 2025 |
| Jessjax Limited | Hospitality | 2024 |
| Jessop Developments Ltd | Administrative & support | 2009 |
| Jessop Park Management Company Limited | Households | 2020 |
| Jessops (Tailors) Limited | Professional & scientific | 1908 |
| Jessy Mathew 2015 Limited | Health & social care | 2014 |
| Jesus Movement Community Interest Company | Information & communication | 2025 |
| Jeswi Property Ltd | Real estate | 2023 |
| JET 200 Services Ltd | Wholesale & retail | 2014 |
| JET Black Valeting Limited | Administrative & support | 2026 |
| JET Building Services Ltd | Construction | 2024 |
| JET Entertainment Ltd | Other services | 2025 |
| JET Executive Travel Limited | Administrative & support | 2024 |
| JET Harris Ltd | Transport & logistics | 2026 |
| JET Machinery Limited | Wholesale & retail | 2008 |
| JET Prop Co. Ltd | Real estate | 2023 |
| JET Spice Aviation UK Ltd | Administrative & support | 2025 |
| JET Through Limited | Water & waste | 2018 |
| Jete Marketing Ltd | Professional & scientific | 2026 |
| Jethavana SRI Lankan Community Centre Ltd | Health & social care | 2025 |
| Jetistik Ltd | Professional & scientific | 2019 |
| Jetjoy Ltd | Wholesale & retail | 2024 |
| Jets Housing Limited | Real estate | 2021 |
| Jets Trading Ltd | Wholesale & retail | 2016 |
| Jetset Draws Limited | Wholesale & retail | 2025 |
| Jetsetgrad Ltd | Education | 2025 |
| Jetsky Limited | Real estate | 2023 |
| Jetson Limited | Wholesale & retail | 2010 |
| Jetspeed Limited | Real estate | 1999 |
| Jetstart Marketing Limited | Professional & scientific | 2020 |
| Jetstream Executive Travel (Leasing) Limited | Education | 2009 |
| Jett Media Limited | Information & communication | 2011 |
| Jett Services Limited | Professional & scientific | 2021 |
| Jetters Limited | Administrative & support | 2022 |
| Jetwash Team Ltd | Construction | 2026 |
| JEV TM Limited | Construction | 2024 |
| Jewel Bouquets Ltd | Wholesale & retail | 2018 |
| Jewel Gold Shine Limited | Wholesale & retail | 2025 |
| Jewel of Vape Ltd | Wholesale & retail | 2021 |
| Jewelcast Limited | Manufacturing | 2001 |
| Jeweldesign Limited | Wholesale & retail | 1992 |
| Jewellers of Great Britain and Ireland Limited | Other services | 1984 |
| Jewellers Vault & Goldsmiths Ltd | Manufacturing | 2025 |
| Jewellery Advisory Centre Limited | Other services | 1974 |
| Jewellery Apartments Limited | Real estate | 2024 |
| Jewellery by Gulmohar Ltd | Wholesale & retail | 2023 |
| Jewellery Quarter Boxes Limited | Wholesale & retail | 2015 |
| Jewellery Quarter Bullion Limited | Wholesale & retail | 2008 |
| Jewellery Quarter Chiropractic Clinic Ltd | Health & social care | 2020 |
| Jewellery Quarter Limited | Other services | 1989 |