| James Swanston Ltd | Wholesale & retail | 2025 |
| Jamie Houston Limited | Wholesale & retail | 2025 |
| Jamil Abdullah Ltd | Construction | 2024 |
| Janco Group Limited | Administrative & support | 2024 |
| Jason L Lowe Ltd | Extraterritorial | 2026 |
| Jaspers Pizza Ltd | Hospitality | 2021 |
| Jasu Limited | Extraterritorial | 2020 |
| JAY Allied Assets (Holdings) Limited | Financial services | 2024 |
| JAY Allied Assets Limited | Administrative & support | 1965 |
| JAY Lawley Garages Limited | Wholesale & retail | 2011 |
| Jayne's Hair Boutique Ltd | Other services | 2012 |
| JB Property Law Services Limited | Professional & scientific | 2012 |
| JB Stock Ltd | Wholesale & retail | 2024 |
| JBW (Halesowen) Limited | Financial services | 2018 |
| JC Structural Modelling Ltd | Construction | 2022 |
| Jcgr Holdings Ltd | Financial services | 2026 |
| JCM Facades Ltd | Construction | 2014 |
| Jcotton Solutions Limited | Real estate | 2018 |
| JDD Services Limited | Information & communication | 2008 |
| JDR Property Holdings Ltd | Real estate | 2024 |
| JEM Tyres (2004) Limited | Manufacturing | 2004 |
| Jemp Dental Limited | Health & social care | 2025 |
| JET Connectivity Ltd | Information & communication | 2022 |
| JET Engineering System Solutions Ltd | Professional & scientific | 2020 |
| Jetstar Properties Limited | Real estate | 2004 |
| Jeyes Carpentry Limited | Construction | 2024 |
| JF & SR Properties Limited | Real estate | 2024 |
| JH Tool Services Limited | Manufacturing | 2025 |
| JHB Installations Limited | Construction | 2021 |
| JIM Shipley Settlement Limited | Financial services | 2013 |
| Jimmy Macks Casual Dining Company Limited | Hospitality | 2016 |
| JJD Contracting Limited | Construction | 2011 |
| JK Chambers Limited | Real estate | 2019 |
| JK Houndsmiths Limited | Other services | 2021 |
| JK Opco Ltd | Real estate | 2019 |
| JK Propco LLP | | 2019 |
| JL Computing Ltd | Information & communication | 2008 |
| JLB Property Holdings Ltd | Real estate | 2025 |
| Jljc Construction Limited | Construction | 2024 |
| JM Envirofuels Limited | Administrative & support | 2009 |
| JMH Projects Limited | Professional & scientific | 2015 |
| JML Commercial Ltd | Wholesale & retail | 2024 |
| JMM REC Group Ltd | Administrative & support | 2024 |
| JMS Golfing Services Ltd | Arts & recreation | 2021 |
| Jn&K Services Ltd | Administrative & support | 2024 |
| JNT Music Limited | Arts & recreation | 2009 |
| JO & Leeanne's Tasty Bites Ltd | Hospitality | 2024 |
| Jobsworth Logistics Recruitment Limited | Extraterritorial | 2026 |
| Jobsworth Managed Services Limited | Administrative & support | 2026 |
| Jobsworth Recruitment Limited | Administrative & support | 2010 |
| Jobsworth Recruitment Solutions (North) Limited | Administrative & support | 2025 |
| Jobsworth Recruitment Solutions Limited | Administrative & support | 2023 |
| Jocpropertsolutions Limited | Households | 2022 |
| Joe's Accountancy Limited | Professional & scientific | 2025 |
| Joel's Healthcare Limited | Health & social care | 2019 |
| John Martin Design Associates Limited | Administrative & support | 1996 |
| John Neale Ltd | Professional & scientific | 2002 |
| John Paddock Supplies Limited | Transport & logistics | 2005 |
| John Wallace Ltd | Wholesale & retail | 2019 |
| John's Butchers Limited | Wholesale & retail | 2012 |
| Johnson Drywall Limited | Construction | 2003 |
| Joyanne Ltd | Information & communication | 2024 |
| Joyce Wilson Consulting Limited | Information & communication | 2022 |
| JP (Worcester) Ltd | Wholesale & retail | 2024 |
| JPM Insurance Advisers Limited | Financial services | 2005 |
| JPM Midlands Limited | Financial services | 2020 |
| JPM Pensions Limited | Financial services | 2013 |
| JPP Demolition Ltd | Construction | 2017 |
| JPS Imports and Liquidation Limited | Wholesale & retail | 2023 |
| JR Diagnostics Limited | Wholesale & retail | 2022 |
| JR Investment Holdings Limited | Real estate | 2017 |
| JRC Property Developments Ltd | Construction | 2024 |
| JRH Costing & Accountancy Limited | Professional & scientific | 1999 |
| JRK Utilities Limited | Construction | 2015 |
| JRL Homes & Lettings Ltd | Real estate | 2026 |
| JS Heronswood Properties Limited | Real estate | 2025 |
| Jscl Limited | Administrative & support | 2023 |
| Jsclogisticsuk Limited | Transport & logistics | 2025 |
| Jscottdesign Ltd | Manufacturing | 2007 |
| Jsds Investments Limited | Real estate | 2024 |
| JSH Batteries Ltd | Manufacturing | 2025 |
| JSH Battery Limited | Manufacturing | 2022 |
| JSH Tissue Viability Ltd | Administrative & support | 2018 |
| Jsira the Cart Limited | Hospitality | 2022 |
| JSV Performance Limited | Wholesale & retail | 2025 |
| JT Business Development Ltd | Professional & scientific | 2016 |
| JT Finance & Consultancy Limited | Professional & scientific | 2023 |
| JTG Plastering & Carpentry Ltd | Construction | 2021 |
| Juke Properties Ltd | Real estate | 2023 |
| JUKE2 Properties Limited | Real estate | 2025 |
| Julbob Properties Limited | Real estate | 2024 |
| Just Gelled Ltd | Other services | 2023 |
| Just US (Homes) LLP | | 2018 |
| Justright Price Limited | Extraterritorial | 2013 |
| JV Orchard Investments Limited | Real estate | 2018 |
| JWB Materials Simulation Limited | Professional & scientific | 2019 |
| JZB 629 Limited | Hospitality | 2023 |
| K B Landscapes Ltd | Administrative & support | 2002 |
| K J Automotive Limited | Wholesale & retail | 2011 |
| K J S Transport Limited | Transport & logistics | 2018 |