| J2 Partners Limited | Real estate | 2021 |
| J3 Leisure Ltd | Construction | 2021 |
| JA Home Interior & Installation Ltd | Construction | 2026 |
| Jackhick Property Ltd | Real estate | 2026 |
| Jackson and Co Builders Limited | Construction | 2019 |
| Jacopa Limited | Water & waste | 2014 |
| Jagpal Transport Ltd | Transport & logistics | 2024 |
| Jagtar Building Solutions Limited | Construction | 2025 |
| JAI Builders Limited | Construction | 2021 |
| JAI Khehra Limited | Transport & logistics | 2023 |
| Jaiveer Ltd | Wholesale & retail | 2021 |
| Jakgur Transport Ltd | Transport & logistics | 2024 |
| Jako POP Ltd | Wholesale & retail | 2021 |
| Jam-Haj Holdings Limited | Financial services | 2026 |
| James Brook Ltd | Construction | 2026 |
| James Dean Designs Limited | Other services | 2025 |
| Jameson Group Limited | Manufacturing | 2019 |
| Jameson Seating Limited | Manufacturing | 1983 |
| Jammu Limited | Construction | 2025 |
| Jamposs Ltd | Wholesale & retail | 2023 |
| Jandali Construction Contractors Limited | Construction | 2024 |
| Jandor Transport Ltd | Transport & logistics | 2017 |
| Janespices Afro Kitchen Limited | Hospitality | 2020 |
| Janga Executive Travel Ltd | Wholesale & retail | 2023 |
| Janyalvi Trade Limited | Manufacturing | 2022 |
| JAP Grewal Transport Ltd | Transport & logistics | 2017 |
| Japji Services Ltd | Transport & logistics | 2024 |
| JAR Consortium Limited | Real estate | 2023 |
| Jarmark Erdington Limited | Administrative & support | 2018 |
| Jarmark Online Limited | Wholesale & retail | 2022 |
| Jaryal Transport Ltd | Transport & logistics | 2026 |
| JAS Commercial Property Ltd | Real estate | 2020 |
| JAS Mobile Mechanic Ltd | Wholesale & retail | 2024 |
| JAS Transport Midlands Ltd | Transport & logistics | 2022 |
| Jasbirwilsonyx Limited | Wholesale & retail | 2025 |
| Jaseid Ltd | Wholesale & retail | 2026 |
| Jasheer Food & Wine UK Limited | Wholesale & retail | 2016 |
| Jasjot Sall Ltd | Health & social care | 2016 |
| Jaskaran UK Limited | Wholesale & retail | 2009 |
| Jasleen Construction Limited | Construction | 2022 |
| Jass Construction (Midland) Ltd | Construction | 2017 |
| Jassal Property Holdings Ltd | Real estate | 2022 |
| Jassigill Limited | Health & social care | 2019 |
| Jatt Construction Limited | Construction | 2004 |
| Jatt.Com Transport Ltd | Transport & logistics | 2026 |
| Jawanda Investment & Properties Ltd | Real estate | 2023 |
| Jaygees Luxury Homes Ltd | Health & social care | 2024 |
| Jazz Electronics Limited | Other services | 2024 |
| JB 1 Ground Engineering Limited | Construction | 2022 |
| JB 1 Plant Hire Limited | Administrative & support | 2020 |
| JB Auto Trimmings Limited | Manufacturing | 2019 |
| JB Real Estate (GB1) Ltd | Real estate | 2025 |
| JB Real Estate (GB2) Ltd | Real estate | 2025 |
| JB Trends Ltd | Wholesale & retail | 2020 |
| JBS Industries Limited | Manufacturing | 1993 |
| JC Contruct Housing Ltd | Hospitality | 2026 |
| JC Quality Solutions Ltd | Professional & scientific | 2019 |
| Jcot UK Ltd | Real estate | 2024 |
| Jedid Company Limited | Administrative & support | 2023 |
| Jedid Properties Limited | Real estate | 2023 |
| Jeemax Ltd | Real estate | 2025 |
| Jeeta Transport Ltd | Transport & logistics | 2022 |
| Jehova Anopa Limited | Health & social care | 2013 |
| JEN Hub CIC | Education | 2023 |
| JEN Sparkle Ltd | Administrative & support | 2023 |
| Jenbar Contractors Limited | Construction | 2019 |
| Jeneye Rennox Ltd | Information & communication | 2025 |
| Jenoside Ltd | Wholesale & retail | 2025 |
| Jepson Properties Ltd | Real estate | 2021 |
| Jetsun's Exterior Maintenance Ltd | Administrative & support | 2025 |
| JH Car Repair Centre Ltd | Wholesale & retail | 2026 |
| Jhaj Transport Ltd | Transport & logistics | 2024 |
| JHD Leisure Limited | Arts & recreation | 2009 |
| JHS Transport Ltd | Transport & logistics | 2021 |
| Jimexpress Limited | Transport & logistics | 2023 |
| Jimo Traffic Management Ltd | Construction | 2025 |
| JIN Jackson Limited | Wholesale & retail | 2024 |
| Jind Kaur Properties Ltd | Real estate | 2025 |
| Jindal Properties Ltd | Real estate | 2021 |
| Jinder Catering Limited | Hospitality | 2023 |
| JJ Enterprisesuk Ltd | Households | 2023 |
| JJ Fixit Ltd | Construction | 2024 |
| JJ Jewellers Ltd | Wholesale & retail | 2022 |
| JJ Parts Midlands Ltd | Wholesale & retail | 2020 |
| Jjam Knight Services Limited | Information & communication | 2018 |
| JJS Mills Engineering Limited | Manufacturing | 2009 |
| JJT Cleaning Company Ltd | Administrative & support | 2019 |
| JK 90 Ltd | Real estate | 2025 |
| JK Aestheticare Ltd | Manufacturing | 2024 |
| JK Decoration Retail Limited | Wholesale & retail | 2020 |
| JK Locuming Ltd | Health & social care | 2022 |
| JK Tools Ltd | Manufacturing | 2023 |
| Jkgoods Ltd | Transport & logistics | 2021 |
| JKL Capital Investments Limited | Real estate | 2025 |
| JKS Agency Limited | Wholesale & retail | 2012 |
| JL & C Properties Ltd | Real estate | 2016 |
| Jl&C Associates Limited | Professional & scientific | 2023 |
| JLB Shipping & Logistics Limited | Transport & logistics | 2016 |
| JLL Vehicle Distribution Limited | Administrative & support | 2010 |
| JLM Productions Limited | Information & communication | 2014 |