| Junction 30 Construction Services Ltd | Wholesale & retail | 2004 |
| Junction 30 Storage Ltd | Administrative & support | 2009 |
| June Hancock Mesothelioma Research Fund | Health & social care | 2007 |
| Juneaura Ltd | Wholesale & retail | 2025 |
| Jungle Mall Ltd | Wholesale & retail | 2018 |
| Junglesale Limited | Hospitality | 2020 |
| Juniper Group Limited | Administrative & support | 2015 |
| Juniper Horizon Outdoor Ltd | Administrative & support | 2025 |
| Juno Books Ltd | Wholesale & retail | 2021 |
| Jupiter Tax Ltd | Professional & scientific | 2018 |
| Jupiter Will Writing Ltd | Administrative & support | 2022 |
| Jups Ltd | Real estate | 2022 |
| Jurassica Ltd | Arts & recreation | 2020 |
| Juristedge Ltd | Information & communication | 2024 |
| Jusoor UK | Health & social care | 2013 |
| Just a Mother Ltd | Real estate | 2019 |
| Just ADD Features Limited | Information & communication | 2018 |
| Just BC Apparel Limited | Wholesale & retail | 2025 |
| Just Bought Your Car Ltd | Wholesale & retail | 2023 |
| Just Coaching Limited | Other services | 2025 |
| Just for Kidz UK Ltd. | Education | 2005 |
| Just Mercedes Benz Ltd | Wholesale & retail | 2024 |
| Just Noey Limited | Administrative & support | 2010 |
| Just One More Beer Ltd | Hospitality | 2022 |
| Just Sharon Limited | Arts & recreation | 2025 |
| Just Sofa Design Ltd | Wholesale & retail | 2026 |
| Just Talent Limited | Information & communication | 2003 |
| Just Teachers Holdings Limited | Financial services | 2007 |
| Just Teachers Limited | Administrative & support | 2005 |
| Just TNK Bars Ltd | Wholesale & retail | 2015 |
| Just Trade Windows Limited | Manufacturing | 2003 |
| Just William Levick Kids Ltd | Health & social care | 2004 |
| Just Windows Limited | Manufacturing | 2005 |
| Justine's Beauty Limited | Other services | 2018 |
| Justine's Hair Limited | Other services | 2018 |
| Justjamie Limited | Hospitality | 2018 |
| Justrading Ltd | Wholesale & retail | 2006 |
| Jutrad Limited | Health & social care | 2010 |
| JV Arts Tower Ltd | Hospitality | 2025 |
| JV Home Letting Limited | Households | 2025 |
| JV Lettings Limited | Households | 2025 |
| JV Rope Access Limited | Professional & scientific | 2019 |
| JVA Consulting Ltd | Professional & scientific | 2025 |
| Jvbm Properties Limited | Real estate | 2025 |
| Jvck James Limited | Information & communication | 2022 |
| JVN Architecture Limited | Professional & scientific | 2007 |
| JVN Design Ltd | Professional & scientific | 2021 |
| JVS (UK) Ltd | Wholesale & retail | 2014 |
| JVU Ltd | Administrative & support | 2018 |
| JW Beauty Limited | Other services | 2022 |
| JW Bullion Ltd | Wholesale & retail | 2021 |
| JW Contractors Limited | Construction | 2026 |
| JW Crawshaw Limited | Wholesale & retail | 1997 |
| JW Financial Consultants Limited | Financial services | 2026 |
| JW Valeting Ltd | Administrative & support | 2025 |
| Jwani Ltd | Wholesale & retail | 2023 |
| JWC Communications Ltd | Information & communication | 2022 |
| JWD Family PUB Co Limited | Hospitality | 2026 |
| JWE Logistics Ltd | | 2009 |
| JWH Design Ltd | Wholesale & retail | 2023 |
| JXA222 Limited | Health & social care | 2009 |
| JY Buns Ltd | Hospitality | 2026 |
| JY Crossings Limited | Construction | 2014 |
| JYJ Property Limited | Real estate | 2026 |
| JZ Clinical Research Consultants Ltd | Information & communication | 2017 |
| J’Pax Living Ltd | Administrative & support | 2026 |
| K & a Builders Services Ltd | Construction | 2023 |
| K & D Diner Limited | Real estate | 2002 |
| K & H Management Limited | Hospitality | 2017 |
| K & J Construction and Developments Limited | Construction | 2019 |
| K & LH Services Limited | Construction | 2004 |
| K & Millar Ltd | Professional & scientific | 2024 |
| K & PA Limited | Administrative & support | 2009 |
| K & S Investment Partnership Limited | Real estate | 2023 |
| K & W Haulage Limited | Transport & logistics | 2003 |
| K ARC Holdings Limited | Financial services | 2021 |
| K B & F Holdings Limited | Real estate | 2016 |
| K C Brown Ltd | Wholesale & retail | 2020 |
| K C Ngineering Surveying Ltd | Construction | 2014 |
| K Curle Properties Limited | Real estate | 2020 |
| K D Building & Renovation Limited | Construction | 2021 |
| K D S Couriers Ltd | Transport & logistics | 2021 |
| K Darren Neale Holdings Ltd | Financial services | 2024 |
| K E Contracting Limited | Real estate | 2007 |
| K G Consultants South Yorkshire Ltd | Professional & scientific | 2025 |
| K Goding Limited | Information & communication | 2008 |
| K Horsfall Limited | Professional & scientific | 2025 |
| K K Global Limited | Other services | 2011 |
| K K Sall Properties Ltd | Real estate | 2022 |
| K L D Property Lettings Limited | Real estate | 2018 |
| K Lane Films Ltd | Information & communication | 2017 |
| K Lilley Delivery Services Limited | Transport & logistics | 2021 |
| K LIU Hair Extensions Limited | Other services | 2023 |
| K M Scaffolding Services Ltd | Construction | 2026 |
| K Naylor Construction Limited | Administrative & support | 2015 |
| K Needham Properties Limited | Real estate | 2018 |
| K P Hogan Utilities Limited | Professional & scientific | 2005 |
| K Phelan Dental Limited | Health & social care | 2024 |
| K Q Consultants Limited | Other services | 2015 |
| K R Corporation Limited | Real estate | 2020 |