| Joy-Sam UK Limited | Wholesale & retail | 2020 |
| Joyce Building Limited | Construction | 2007 |
| Joyce Green Lane (Dartford) Management Company Limited | Households | 1994 |
| Joyce Groundworks Limited | Construction | 2025 |
| Joyce's Palace Ltd | Hospitality | 2022 |
| Joyford Passage RTM Company Limited | Households | 2014 |
| Joylrama Healthcare Ltd | Administrative & support | 2025 |
| JP 1 Consulting Corp Ltd | Professional & scientific | 2024 |
| JP Consultancy Advisory Services Limited | Professional & scientific | 2026 |
| JP Tech Management Services Limited | Information & communication | 2014 |
| JP Transporters Ltd | Transport & logistics | 2024 |
| JPA Care Services Ltd | Administrative & support | 2017 |
| JPA Cleaning Services Ltd | Other services | 2023 |
| Jpbc Ltd | Construction | 2015 |
| JPD Propco Ltd | Real estate | 2021 |
| JPF Advisory Services Ltd | Professional & scientific | 2018 |
| Jpkm Trades Limited | Administrative & support | 2024 |
| JPM Mechanical Services (UK) Limited | Construction | 2024 |
| JPN Group Limited | Information & communication | 2025 |
| JPR Electrical - Plumbing & GAS Ltd | Construction | 2021 |
| JPR Fibre Ltd | Information & communication | 2025 |
| JPS & Associates Ltd | Construction | 2024 |
| JPS Coffee & Tea Ltd | Hospitality | 2025 |
| JR Property Consultancy Ltd | Real estate | 2025 |
| JR Shiv Investment Ltd | Real estate | 2024 |
| JRD Contractors Ltd | Construction | 2011 |
| JRD Healthcare Limited | Real estate | 2008 |
| JRD Investment Properties Ltd | Real estate | 2023 |
| JRM Services (London) Ltd | Other services | 2022 |
| Jrvs Store Ltd | Wholesale & retail | 2025 |
| Jrvs Trading Ltd | Hospitality | 2025 |
| JS & K Consultancy Ltd | Information & communication | 2024 |
| JS Event Solutions Limited | Hospitality | 2026 |
| JS Golf Limited | Arts & recreation | 2025 |
| JS Index Limited | Information & communication | 2017 |
| JSA Properties Legacy LLP | | 2021 |
| JSA Property (Commercial) Ltd | Real estate | 2020 |
| JSA Property (GT) Limited | Real estate | 2021 |
| JSA Property (Horizon) Ltd | Real estate | 2022 |
| JSA Property Holdings Limited | Financial services | 2020 |
| Jsainnovations Ltd | Information & communication | 2025 |
| JSB Property Solutions Limited Limited | Real estate | 2024 |
| JSN Builders Ltd | Construction | 2022 |
| JSP Estates Limited | Real estate | 2002 |
| JSS Brickwork Ltd | Construction | 2026 |
| JSS Madeira Builders Ltd | Construction | 2012 |
| JT Business Brook Ltd | Administrative & support | 2013 |
| JT Design Associates Ltd | Professional & scientific | 2019 |
| JT Escrow Logistics Services Limited | Transport & logistics | 2025 |
| JT Glass & Glazing Ltd | Construction | 2025 |
| JT Metalworks Ltd | Construction | 2011 |
| JT Motion Design Ltd | Professional & scientific | 2019 |
| JT Tattooists Limited | Other services | 2015 |
| JTS Property Investments Ltd | Real estate | 2025 |
| Jubbernaut Limited | Information & communication | 2016 |
| Jubilee Apartments Ltd | Real estate | 2025 |
| Jubilee Court (Loughborough) Management Company Limited | Households | 2002 |
| Jubilee Court (Loughborough) Management Company NO. 2 Limited | Households | 2003 |
| Jubilee Court (Thornton Heath) Limited | Households | 1988 |
| Jubilee Enterprise (CRP) Limited | Real estate | 2016 |
| Jubilee Gardens (Euxton) Management Company Ltd | Households | 2023 |
| Judah Homes Ltd | Real estate | 2021 |
| Jufaryjjegroup Limited | Manufacturing | 2025 |
| Juice IT Limited | Manufacturing | 2019 |
| JUK Management Services Ltd | Information & communication | 2013 |
| Juli Komar Ltd | Wholesale & retail | 2024 |
| Julie’S Nails Limited | Other services | 2018 |
| Julihas Limited | Health & social care | 2015 |
| Jumana's Dance and Fashion Academy London Limited | Arts & recreation | 2020 |
| Jump Training Ltd | Professional & scientific | 2006 |
| Junebug Luxury Concierge and Lifestyle Ltd | Other services | 2019 |
| Jungelstudio Ltd | Professional & scientific | 2026 |
| Jungle BOI Entertainment Limited | Information & communication | 2016 |
| Junior Chessuk | Education | 2005 |
| Junior Vips Nursery Limited | Education | 2016 |
| Junk Food Limited | Hospitality | 2013 |
| Junk Taxi Limited | Water & waste | 2020 |
| Juole Consultancy Limited | Information & communication | 2017 |
| Juole Properties Limited | Real estate | 2020 |
| Jupiter's Teachings Ltd | Wholesale & retail | 2024 |
| JUQ Roual Transport Ltd | Transport & logistics | 2018 |
| Jura Spray Group Limited | Construction | 2020 |
| Jurassic Barks Pet Service Ltd | Other services | 2015 |
| Jurita Limited | Education | 2021 |
| Juse Collection Ltd | Wholesale & retail | 2025 |
| Just & Legal Ltd | Professional & scientific | 2019 |
| Just 4 Linen Limited | Hospitality | 2004 |
| Just a Bite Ltd | Hospitality | 2012 |
| Just DO IT Once Ltd | Education | 2019 |
| Just Family Business Ltd | Hospitality | 2017 |
| Just Flutes Limited | Wholesale & retail | 2023 |
| Just GAS Services Ltd | Mining & quarrying | 2024 |
| Just Minicab Ltd | Transport & logistics | 2018 |
| Just MO Luxury Ltd | Wholesale & retail | 2017 |
| Just Movers Ltd | Transport & logistics | 2025 |
| Just Shoes Limited | Wholesale & retail | 2025 |
| Just Solace Ltd | Transport & logistics | 2025 |
| Just Step Ltd | Information & communication | 2025 |
| Just Worthing Limited | Other services | 2014 |
| Justcomputers Ltd | Wholesale & retail | 2020 |