| ISR Trade Link Ltd | Wholesale & retail | 2024 |
| Istrel Limited | Professional & scientific | 2015 |
| It's in the Detail Ltd | Administrative & support | 2025 |
| Italian Tours Ltd | Administrative & support | 2019 |
| Itanks and Valves Limited | Other services | 2018 |
| Itsin Transit Removals & Storage Ltd | Transport & logistics | 2017 |
| Iulian Daniel Ltd | Transport & logistics | 2026 |
| Iventis Ltd | Information & communication | 2015 |
| IVY Light Ltd | Health & social care | 2024 |
| IXC UK Limited | Professional & scientific | 2018 |
| Ixion Finance Ltd | Real estate | 2010 |
| Izan Business Solutions Limited | Information & communication | 2023 |
| Izzy's Lazy Days Hot TUB Breaks Ltd | Real estate | 2020 |
| J & a Delivery Ltd | Transport & logistics | 2016 |
| J & a Turner Poultry Limited | Agriculture & fishing | 2018 |
| J & a Turner Transport Ltd | Transport & logistics | 2025 |
| J & B LEE Roofing Limited | Construction | 2025 |
| J & B Park Homes Limited | Hospitality | 2016 |
| J & C Engineering Services Limited | Professional & scientific | 2004 |
| J & C Pipelines Limited | Transport & logistics | 2022 |
| J & E Designs Ltd | Manufacturing | 2017 |
| J & J.H.Hall (Welton) Limited | Agriculture & fishing | 1953 |
| J & K Bell Limited | Administrative & support | 2006 |
| J & L Drive Ltd | Transport & logistics | 2025 |
| J & M Mcgurk Limited | Health & social care | 2024 |
| J & R Armstrong Farms Limited | Agriculture & fishing | 2003 |
| J & S Heating and Cooling Ltd | Construction | 2025 |
| J & Sun Limited | Other services | 2024 |
| J & V Casey and SON Limited | Agriculture & fishing | 2003 |
| J a a Developments Ltd | Construction | 2025 |
| J a Gaughan Limited | Construction | 2025 |
| J a Hale Limited | Administrative & support | 2019 |
| J a Holdings Limited | Financial services | 2008 |
| J a Marketing Limited | Professional & scientific | 2026 |
| J B Farming Enterprises Ltd | Hospitality | 2009 |
| J Bowler Interior Drywall Ltd | Construction | 2016 |
| J Brennan Limited | Construction | 2005 |
| J C Morley Plumbing & Heating Ltd | Other services | 2007 |
| J Charnley Limited | Professional & scientific | 2017 |
| J D Clay Limited | Construction | 2006 |
| J D Hadfield Ltd | Manufacturing | 2025 |
| J D Harrison Limited | Construction | 2018 |
| J D Innovations Ltd | Professional & scientific | 2009 |
| J D Marshall Property Investments Limited | Real estate | 2021 |
| J D OIL and GAS Limited | Construction | 2015 |
| J Dyson Ltd | Wholesale & retail | 2025 |
| J F Finnegan (Parkway) Limited | Construction | 1998 |
| J G Porter Limited | Agriculture & fishing | 2012 |
| J Good Properties Ltd | Construction | 2018 |
| J Good Services Ltd | Manufacturing | 2017 |
| J Gotto Ltd | Health & social care | 2018 |
| J H G Agri Services Ltd | Agriculture & fishing | 2024 |
| J H Management Solutions Limited | Information & communication | 2012 |
| J H Warusavitarne Ltd | Health & social care | 2017 |
| J Harcourt Limited | Health & social care | 2009 |
| J Holt Consulting Limited | Professional & scientific | 2018 |
| J I Cameron Limited | Financial services | 2016 |
| J J Lincs Ltd | Information & communication | 2013 |
| J K Broadcasting Limited | Professional & scientific | 2006 |
| J K Classics Limited | Wholesale & retail | 2021 |
| J K V M Holdings Limited | Financial services | 2021 |
| J K Vehicle Movements Limited | Transport & logistics | 2007 |
| J K Wardman Limited | Information & communication | 2024 |
| J Kelly Electrical Ltd | Construction | 2003 |
| J Krupa Medical Ltd | Health & social care | 2011 |
| J Lomas Properties Limited | Real estate | 2025 |
| J Lovell Property Ltd | Real estate | 2025 |
| J M Cross Ltd | Information & communication | 2019 |
| J M Gibson Limited | Construction | 2007 |
| J M H Directional Drilling Limited | Construction | 1997 |
| J Miles Plastering Ltd | Construction | 2026 |
| J Mills Oncology Services Ltd | Health & social care | 2011 |
| J Musson Building and Civils Limited | Construction | 2019 |
| J N & Z Armitage Ltd | Health & social care | 2013 |
| J Needham Holdings Ltd | Financial services | 2025 |
| J P S a Consulting Limited | Professional & scientific | 1993 |
| J P Stuart Transport Ltd | Transport & logistics | 2018 |
| J P Window Cleaning Ltd | Administrative & support | 2012 |
| J R Andrews Limited | Health & social care | 2011 |
| J R S Development Ltd | Construction | 2006 |
| J Reid Medical Services Ltd | Health & social care | 2017 |
| J Riley Painting & Decorating Limited | Construction | 2020 |
| J S Construction Building Contractors Limited | Construction | 2021 |
| J Sampson Driving Ltd | Transport & logistics | 2013 |
| J Switch Services Limited | Construction | 2025 |
| J Taylor Plumbing Ltd | Construction | 2025 |
| J Vitols Ltd | Transport & logistics | 2022 |
| J Y LIM Consulting Ltd | Professional & scientific | 2017 |
| J&L Property Refurbishments Ltd | Real estate | 2025 |
| J&O IPS Ltd | Hospitality | 2024 |
| J&P Enterprise Vision Limited | Wholesale & retail | 2023 |
| J&W Family Limited | Hospitality | 2025 |
| J'S Soulfood Ltd | Hospitality | 2025 |
| J-Pac Transport Ltd | Transport & logistics | 2024 |
| J. & R. Properties Limited | Real estate | 1968 |
| J. H Equipment Ltd | Wholesale & retail | 2010 |
| J. Norcross Limited | Agriculture & fishing | 1977 |
| J. Sperskis Transport Limited | Transport & logistics | 2016 |
| J. Wilkins Limited | Construction | 1997 |
| J.A. Andrew & SON Co. Limited | Construction | 1984 |