| JM Healthcare Support Ltd | Health & social care | 2026 |
| JM Law Consultant Ltd | Professional & scientific | 2018 |
| JMA Engineering Ltd | Professional & scientific | 2016 |
| Jmbe Ltd | Health & social care | 2013 |
| JMC Trading Limited | Professional & scientific | 2003 |
| Jmft Ltd | Health & social care | 2022 |
| JMG Support and Healthcare Services Ltd Limited | Transport & logistics | 2020 |
| Jmgv Ltd | Real estate | 2021 |
| JMJ Consultants Limited | Professional & scientific | 2009 |
| JMS Capital Partners Ltd | Financial services | 2024 |
| JMS Consult Ltd | Other services | 2021 |
| JMS Group Holdings Ltd | Financial services | 2015 |
| JMS Housing Group CIC | Financial services | 2024 |
| JMS Housing Investments Ltd | Real estate | 2025 |
| JMS Housing Management Ltd | Real estate | 2024 |
| JMS Private Clients Ltd | Financial services | 2015 |
| JMS Property Investments (London) Ltd | Extraterritorial | 2015 |
| JMS Retail Services Ltd | Extraterritorial | 2014 |
| JMS Secure Data Ltd | Information & communication | 2013 |
| Jmsretail Ltd | Professional & scientific | 2019 |
| Jmtc Project Management Services Limited | Administrative & support | 2012 |
| JN Skips Ltd | Water & waste | 2021 |
| Jndee Invest Limited | Real estate | 2020 |
| Jndee Limited | Wholesale & retail | 2006 |
| Jndee Projects Limited | Construction | 2024 |
| Jndee Tech Limited | Information & communication | 2025 |
| JNL Cleary Ltd | Administrative & support | 2026 |
| JNM Perio Limited | Health & social care | 2024 |
| JNR Estates Limited | Real estate | 2026 |
| JNR Ultimate Productions Limited | Other services | 2024 |
| JNV Chick'N Lounge Ltd | Hospitality | 2022 |
| JO & Bloom Limited | Wholesale & retail | 2025 |
| Jo-Essel Limited | Wholesale & retail | 2018 |
| Joal Miez Holdings Ltd | Hospitality | 2021 |
| Joalen Ltd | Wholesale & retail | 2021 |
| Joanish Ltd | Real estate | 2018 |
| Joaquim Builders & Plumbers Ltd. | Construction | 2021 |
| Joaquim the Builder Ltd. | Administrative & support | 2019 |
| JOB Card Renewal Limited | Wholesale & retail | 2025 |
| JOB Creek Services Limited | Administrative & support | 2025 |
| JOB Initiative Ltd | Education | 2026 |
| Jobjectory Ltd | Information & communication | 2024 |
| Jobplus Consult Ltd | Real estate | 2020 |
| Jobplus Consultancy Ltd | Education | 2016 |
| Jobs-Connect Ltd | Administrative & support | 2023 |
| Jocelyn Cares Domiciliary Limited | Health & social care | 2019 |
| Jockey Road Management Company Limited | Households | 2006 |
| Jodies Salon and Services Ltd | Other services | 2020 |
| Jodies Tattoos Ltd | Arts & recreation | 2019 |
| Joel Nursery Ltd | Education | 2020 |
| Joenal Ltd | Wholesale & retail | 2021 |
| Joenat Child Care Limited | Health & social care | 2023 |
| Joese Cleaning Services Ltd | Administrative & support | 2023 |
| Jofish Media Ltd | Arts & recreation | 2019 |
| Joggins and Partners Ltd. | Construction | 2018 |
| Johe Consultancy Ltd | Information & communication | 2025 |
| John Bentley Consulting Limited | Information & communication | 2016 |
| John Builders Ltd | Construction | 2023 |
| John Cobb Consulting Limited | Construction | 2011 |
| John Kenny Construction Management Ltd | Other services | 2013 |
| John ORD Fiction Ltd | Information & communication | 2026 |
| John Steele Technical Services Limited | Professional & scientific | 2006 |
| John's Cornucopia Ltd. | Wholesale & retail | 2018 |
| Johnagency Ltd | Education | 2013 |
| Johnny & Amelia Limited | Hospitality | 2016 |
| Johnson Rochford Ltd | Information & communication | 2014 |
| Johnson's & Co Properties Ltd | Real estate | 2023 |
| Johnsons Homes Management Ltd | Construction | 2025 |
| Joint Digital Unit Ltd | Other services | 2019 |
| Joint Dynamics Limited | Administrative & support | 2017 |
| Jojo Motors Ltd | Wholesale & retail | 2016 |
| Jolens Limited | Wholesale & retail | 2016 |
| Jolly & Friends Play Town Ltd | Arts & recreation | 2026 |
| Jomag Limited | Real estate | 2022 |
| Jomima Limited | Administrative & support | 2003 |
| JON Attenborough Photography Ltd | Professional & scientific | 2015 |
| Jonathan Dann Ltd | Professional & scientific | 2024 |
| Jonathan MAY Motion Design Ltd | Professional & scientific | 2022 |
| Jonathan Monk LLP | | 2010 |
| Jonathan VEE Associates Limited | Professional & scientific | 2003 |
| Jones & Jones Logistics Ltd | Transport & logistics | 2019 |
| Jones and Co Property Management Ltd | Real estate | 2012 |
| Jones Plumbing Supplies (Croydon) Limited | Wholesale & retail | 1993 |
| Jonicsun UK Limited | Information & communication | 2016 |
| Joose Ltd | Information & communication | 2023 |
| Joralbe Ltd | Hospitality | 2022 |
| Jordan’S Catering Engineering Ltd | Manufacturing | 2025 |
| Jordyn Trading Limited | Financial services | 2024 |
| Josak Care and Recruitment Ltd | Health & social care | 2018 |
| Josens (UK) Limited | Wholesale & retail | 2013 |
| Joseph Akono Bilongo Ltd | Public administration | 2021 |
| Joseph Services Limited | Construction | 2025 |
| Josephmedia Ltd | Professional & scientific | 2010 |
| Josetrade Ltd | Wholesale & retail | 2025 |
| Josh Hair and Beuaty Ltd | Other services | 2024 |
| Joshi Business Solutions Ltd | Information & communication | 2024 |
| Jossywilliams International Limited | Health & social care | 2023 |
| Jothad Global Company Limited | Other services | 2018 |
| Joy & Gladness Ltd | Hospitality | 2021 |
| Joy & Gladness Stalls Ltd | Hospitality | 2025 |