| ITS Elixir (UK) Limited | Wholesale & retail | 2004 |
| Itsm Consultancy Ltd | Information & communication | 2020 |
| Ivinson & Sons 24/7 Limited | Wholesale & retail | 2022 |
| Ivison Quality Consulting Limited | Professional & scientific | 2018 |
| IVY House Farming Ltd | Agriculture & fishing | 2024 |
| IVY Lane Wetheral Management Company Limited | Households | 2022 |
| J & J Energi Limited | Real estate | 2023 |
| J & J Miller Limited | Real estate | 2011 |
| J & J Nichol Limited | Manufacturing | 2013 |
| J & L Couriers Limited | Transport & logistics | 2010 |
| J & S Furness Limited | Wholesale & retail | 2006 |
| J & V Risk Solutions Ltd | Financial services | 2015 |
| J & Y Property Group Ltd | Real estate | 2022 |
| J a Johnston Transport Limited | Transport & logistics | 2003 |
| J and M Therapies Ltd | Wholesale & retail | 2022 |
| J Armstrong Stonemasonry & Brickwork Limited | Construction | 2011 |
| J Castley Engineering Ltd | Professional & scientific | 2021 |
| J Coady Engineering Services Ltd | Professional & scientific | 2023 |
| J D Bamber Holdings Limited | Financial services | 2021 |
| J D Lovatt Limited | Financial services | 2014 |
| J Dickinson Courier Service Limited | Administrative & support | 2011 |
| J Dickinson Transport Limited | Transport & logistics | 2000 |
| J Dodds & Co Property Limited | Real estate | 2018 |
| J F Black & Sons Limited | Extraterritorial | 2012 |
| J F Hill (Carlisle) Limited | Hospitality | 2013 |
| J F Safety Consultancy Ltd | Professional & scientific | 2025 |
| J Jackson Joiner Ltd | Construction | 2008 |
| J K Fabrications (UK) Limited | Manufacturing | 2003 |
| J K Pollock Limited | Administrative & support | 2011 |
| J K Williamson Limited | Hospitality | 2002 |
| J Meekley Courier Services Ltd | Transport & logistics | 2024 |
| J Midgley Floorshop Ltd | Wholesale & retail | 2023 |
| J O'Neil Commercials Limited | Wholesale & retail | 2026 |
| J Potts Logistics Ltd | Transport & logistics | 2020 |
| J Sea 3 Ltd | Wholesale & retail | 2022 |
| J W Shearing Limited | Agriculture & fishing | 2016 |
| J W Vevers Agricultural Services Limited | Agriculture & fishing | 2012 |
| J&C Watson Ltd | Manufacturing | 2025 |
| J&D Polish Food Ltd | Real estate | 2011 |
| J&M Publishing Ltd | Wholesale & retail | 2024 |
| J'S Indian Restaurant Ltd | Hospitality | 2024 |
| J-Clean Professional Ltd | Administrative & support | 2015 |
| J-Mack Properties Limited | Real estate | 2024 |
| J. Balchin & SON Limited | Wholesale & retail | 1986 |
| J. C. Bowker & Co. | Agriculture & fishing | 2006 |
| J. Cregan Ltd | Water & waste | 2007 |
| J.B Countryside Services Ltd | Agriculture & fishing | 2017 |
| J.E. Foster & SON Limited | Construction | 1998 |
| J.E. Massey Limited | Real estate | 1994 |
| J.G.Armstrong Holdings Limited | Real estate | 1961 |
| J.H & Sons Ltd | Real estate | 2025 |
| J.H. Wood & SON Limited | Hospitality | 1940 |
| J.J. Lattimer Builders Limited | Extraterritorial | 2014 |
| J.R. Richardson Limited | Wholesale & retail | 1988 |
| J4R Limited | Administrative & support | 2008 |
| JA Carlisle Delivery Ltd | Transport & logistics | 2025 |
| JA Light Commercials Ltd | Administrative & support | 2026 |
| JAC Structural Engineering Ltd | Professional & scientific | 2015 |
| Jack and Jill Nursery Limited | Education | 2003 |
| Jack Trewhitt Golf Limited | Arts & recreation | 2020 |
| Jacked Lettuce Ltd | Hospitality | 2026 |
| Jackson & Brown Limited | Wholesale & retail | 2023 |
| Jackson Rickerby Limited | Financial services | 2015 |
| Jackson Werks Ltd | Administrative & support | 2018 |
| Jackson's Road Haulage Ltd | Manufacturing | 2025 |
| Jacob Davis Limited | Information & communication | 2025 |
| JAI Bolenath Groups Ltd | Wholesale & retail | 2025 |
| JAK & Ellis Ices Limited | Wholesale & retail | 2025 |
| Jalal Wholesale Limited | Wholesale & retail | 2025 |
| James Andrew Johnson Ltd | Extraterritorial | 2024 |
| James Duffield Close Management Company Limited | Extraterritorial | 2012 |
| James Gibson Holdings Limited | Wholesale & retail | 2025 |
| James Jardine Longtown Limited | Agriculture & fishing | 2009 |
| James Learning & Development Limited | Education | 2017 |
| James Noble EDT Limited | Professional & scientific | 2014 |
| James Pringle Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch Woollen Mill Limited | Extraterritorial | 1987 |
| James W a Cruickshank Business Services Ltd | Professional & scientific | 2010 |
| James Webster Consultancy Ltd | Professional & scientific | 2015 |
| James's Scrap Metal Services Limited | Wholesale & retail | 2026 |
| Jamieson and Jamieson Ltd | Administrative & support | 2020 |
| Jarez Limited | Other services | 2017 |
| Jarvis Independent Social Work Ltd | Health & social care | 2021 |
| Jason Robley Limited | Agriculture & fishing | 2015 |
| Jassico Ltd | Information & communication | 2011 |
| Jaybee (Blake) Limited | Wholesale & retail | 1954 |
| Jayie & Company Limited | Extraterritorial | 2022 |
| Jayline Ltd | Construction | 2022 |
| Jaynam Properties Ltd | Real estate | 2023 |
| Jayne Robinson Limited | Extraterritorial | 2012 |
| Jaysass Limited | Public administration | 2024 |
| Jazzpower Limited | Wholesale & retail | 1999 |
| JB Nutrition (Carlisle) Limited | Wholesale & retail | 2013 |
| JBL (North) Ltd | Financial services | 2021 |
| JBP (Carlisle) Ltd | Real estate | 2025 |
| JBR16 Ltd | Professional & scientific | 2023 |
| JBS Roofing and Home Maintenance Ltd | Construction | 2024 |
| JBZ Rentals Limited | Real estate | 2026 |
| JC Car & Commercials Limited | Wholesale & retail | 2021 |
| Jchr Ltd | Transport & logistics | 2026 |
| JCR Corporate Finance Ltd | Professional & scientific | 2021 |