| Jess and ED Coaching Limited | Education | 2022 |
| JET AHU Limited | Construction | 2002 |
| JET Environmental Group Limited | Construction | 2021 |
| JET Environmental Limited | Extraterritorial | 2023 |
| JET Environmental Systems Limited | Construction | 1999 |
| JET Group Holdings Limited | Financial services | 2021 |
| Jevons Tools Limited | Professional & scientific | 1915 |
| Jewaan & Sons Ltd | Other services | 2020 |
| JF6 Properties Ltd | Real estate | 2025 |
| JFA Equine Livery Ltd | Other services | 2024 |
| JFA Investments Ltd | Administrative & support | 2025 |
| JFL Property Solutions Ltd | Construction | 2023 |
| JFM Digital Ltd | Information & communication | 2026 |
| JFR Sunflowers Limited | Real estate | 2024 |
| JG Direct Services Ltd | Administrative & support | 2016 |
| JG Networking Limited | Administrative & support | 2019 |
| JGD Estates Limited | Real estate | 2023 |
| Jgms Services Ltd | Information & communication | 2016 |
| Jgms Solutions Ltd | Professional & scientific | 2011 |
| Jgod Limited | Information & communication | 2001 |
| JGS Properties Limited | Real estate | 1996 |
| JH Agencies Limited | Wholesale & retail | 2017 |
| JH Building & Property Services Ltd | Construction | 2022 |
| JH Housing Limited | Real estate | 2017 |
| JH23 Photography Ltd | Professional & scientific | 2024 |
| JHC Limited | Professional & scientific | 2021 |
| JHD Enterprise Limited | Information & communication | 2023 |
| JHG (Midlands) Limited | Arts & recreation | 2021 |
| JHJ Plumbing & Heating Ltd | Construction | 2023 |
| JHM Transport Limited | Transport & logistics | 2024 |
| JHS Interiors Limited | Wholesale & retail | 2018 |
| Jiang and Zhou Limited | Other services | 2011 |
| Jianingsun Ltd | Real estate | 2025 |
| JIC Logistics Limited | Transport & logistics | 2024 |
| JIC Transport Ltd | Transport & logistics | 2024 |
| Jiggs Limited | Other services | 2005 |
| Jigsaw Joinery & Property Solutions Ltd | Manufacturing | 2020 |
| Jigsoar Ltd | Wholesale & retail | 2024 |
| Jillani & Co Limited | Professional & scientific | 2018 |
| JIM Lavery Law Limited | Professional & scientific | 2016 |
| Jimeny Ltd | Real estate | 2017 |
| Jinja Property Services Limited | Real estate | 2025 |
| Jinja Rentals Limited | Real estate | 2025 |
| Jite Properties Ltd | Real estate | 2021 |
| Jiti Ltd | Information & communication | 2024 |
| Jivan Kalyan IT Solutions Ltd | Information & communication | 2025 |
| Jiyavarni Property Services Limited | Real estate | 2024 |
| JJ Properties Birmingham Limited | Real estate | 2014 |
| JJ Singh Property Limited | Real estate | 2019 |
| JJB Industrial Roofing Ltd | Construction | 2025 |
| Jjoela Limited | Construction | 2016 |
| JJS Group Ltd | Hospitality | 2018 |
| JJS Works Ltd | Professional & scientific | 2025 |
| JJT Mcdaid Limited | Construction | 2011 |
| JK Fabrics & Design Limited | Other services | 2015 |
| JK Language Services Europe Ltd | Professional & scientific | 2013 |
| Jkays Limited | Professional & scientific | 2003 |
| JKC Accountancy Limited | Professional & scientific | 2022 |
| JKD Consulting Ltd | Information & communication | 2023 |
| Jkrj Limited | Construction | 2006 |
| JL Communications Consulting Limited | Professional & scientific | 2019 |
| JL Homes Solihull Limited | Construction | 2017 |
| JLA Automotive Services Ltd | Wholesale & retail | 2004 |
| JLC Communications Ltd | Information & communication | 2018 |
| JLL Consortium Limited | Financial services | 2018 |
| Jllb Catering Limited | Hospitality | 2023 |
| JLM Associates Limited | Other services | 2017 |
| JLS Bookkeeping Ltd | Professional & scientific | 2020 |
| JLS Consultants Ltd | Professional & scientific | 2021 |
| JLS Educational Services Limited | Education | 2022 |
| JLW Telecoms Limited | Information & communication | 2011 |
| JM Business Management Limited | Professional & scientific | 2020 |
| JM Garden & Landscaping Ltd | Administrative & support | 2020 |
| JM Production Group Limited | Information & communication | 2016 |
| Jmac Developments Ltd | Construction | 2022 |
| Jmac Plant Ltd | Administrative & support | 2025 |
| Jmac Property Group Ltd | Construction | 2025 |
| JMC (Contract Installations) Ltd | Construction | 2012 |
| JMK (Midlands) Limited | Real estate | 1988 |
| JMK Floors Ltd | Construction | 2025 |
| JMM Music Limited | Education | 2025 |
| JMR Patel Ltd | Wholesale & retail | 2024 |
| JMX Medical Limited | Health & social care | 2017 |
| JN Medical Ltd | Wholesale & retail | 2018 |
| JNC Commercial Cleaning Services Ltd | Administrative & support | 2025 |
| JO Edden Textile Design Limited | Professional & scientific | 2016 |
| JO Macbean Physiotherapy Limited | Health & social care | 2019 |
| JO MAX Builders Ltd | Information & communication | 2025 |
| Joal Interiors Limited | Professional & scientific | 2004 |
| JOB Planning Consultancy Ltd | Health & social care | 2015 |
| Job's Close Residential Home for the Elderly | Health & social care | 2003 |
| JOE Dibble Digital Limited | Information & communication | 2013 |
| JOE Slater & Sons Builders Ltd | Construction | 2019 |
| Johara Diamonds Ltd | Wholesale & retail | 2016 |
| John Alexander Trading Limited | Professional & scientific | 2014 |
| John Blakey Ltd | Education | 2012 |
| John Bowen & Sons Limited | | 1900 |
| John Buckley (DRY Cleaners) Limited | Other services | 1978 |
| John Earle & SON LLP | | 2007 |
| John Ford Construction Ltd | Construction | 2023 |