| Industrial Wholesale Supplies (NO.1.) Limited | Professional & scientific | 2002 |
| Inet Comms Ltd | Information & communication | 2023 |
| Infomata Limited | | 1982 |
| Inforisca Services Limited | Professional & scientific | 2003 |
| Informed Consultancy Limited | Information & communication | 1999 |
| Informed Solutions (International) Limited | Information & communication | 1997 |
| Informed Solutions Limited | Information & communication | 1992 |
| Initial Safety Services Limited | Administrative & support | 2003 |
| Inkfinity Ltd | Wholesale & retail | 2025 |
| Inprint Colour Limited | Manufacturing | 2002 |
| Insignia Dental Laboratory Limited | Health & social care | 1994 |
| Inspired Interactive Limited | Information & communication | 2007 |
| Inspiring Travel 2024 Limited | Extraterritorial | 2024 |
| Integrated Design Engineering Associates Ltd | Information & communication | 1991 |
| Intelligent Monitoring Systems Limited | Information & communication | 1992 |
| Interlar Limited | | 1987 |
| International Power Supplies Limited | Wholesale & retail | 2003 |
| Invisible Thread Trading Limited | Wholesale & retail | 2006 |
| Invoice Central Ltd | Extraterritorial | 2006 |
| Ionalysis Limited | Manufacturing | 1982 |
| Ironglint Limited | Wholesale & retail | 2026 |
| Iros Arboriculture Ltd | Professional & scientific | 2023 |
| IT Facilitas Limited | Information & communication | 2002 |
| IT Impact Limited | Information & communication | 2003 |
| Itms Computer Software Limited | Information & communication | 1996 |
| Ivan Probert Limited | Information & communication | 2002 |
| Ivan Stockdale Limited | Professional & scientific | 2008 |
| J & J Hennerley Limited | Construction | 2002 |
| J G TEC Limited | Wholesale & retail | 1999 |
| J L E Entertainment Limited | Arts & recreation | 2007 |
| J Norris Associates Limited | Professional & scientific | 2007 |
| J P M Engineering Limited | Administrative & support | 2003 |
| J R Gardening Services Ltd | Administrative & support | 2003 |
| J S Trophies Ltd | Wholesale & retail | 2006 |
| J Shepherd Welding Limited | Construction | 2017 |
| J W Superstore Ltd | Wholesale & retail | 2023 |
| J W Walsh Accountants Limited | Professional & scientific | 2006 |
| J&D Building and Renovations Ltd | Construction | 2022 |
| J. & J. Bower Limited | | 1973 |
| J. Glynn & Associates Ltd | Professional & scientific | 2002 |
| J. Shaughnessy & Sons Limited | Professional & scientific | 1955 |
| J.C. Builders Limited | Construction | 1989 |
| J.E.B. Precision Limited | Manufacturing | 1973 |
| J.E.Dean(Hazel Grove)Limited | Construction | 1970 |
| J.F. Bibby (Truck Sales) Limited | Transport & logistics | 1988 |
| J.M.R. Engineering Services Ltd | Manufacturing | 1998 |
| J.S. Burstow Limited | Construction | 2003 |
| J.S.Oil Company Limited | Manufacturing | 1955 |
| J.Sarsfield & Sons Limited | Water & waste | 1962 |
| J.T. Transport Ltd | Transport & logistics | 2023 |
| J.W.P. Colour Printers Limited | Manufacturing | 1973 |
| J3 Building Solutions (N.E.) Limited | Construction | 2022 |
| Jack Baker & SON Limited | Construction | 2006 |
| Jackson & SON Limited | Wholesale & retail | 1986 |
| Jackson O'Malley Craft Butchers Limited | Wholesale & retail | 2006 |
| Jackson-Stops & Staff (North-West) Limited | Real estate | 1992 |
| Jacob & Jacob Properties Ltd | Real estate | 2018 |
| JAG Estate Agents Ltd | Real estate | 2007 |
| Jambert Limited | Manufacturing | 2006 |
| James Doyle Limited | Health & social care | 1997 |
| James French Construction Limited | Construction | 2005 |
| James Lawrence Homes Limited | Construction | 1997 |
| James Paddock Limited | Wholesale & retail | 2002 |
| James Pemberton Properties Limited | Financial services | 1928 |
| James Young Limited | Professional & scientific | 1997 |
| Jamieson AE Limited | Construction | 2021 |
| Janes Exchange Ltd | Wholesale & retail | 2005 |
| Janice Clare Consultancy Limited | Professional & scientific | 2006 |
| Janrae Management Services Ltd | Administrative & support | 2014 |
| Jantrad Limited | Hospitality | 2002 |
| Jarrett Associates | | 1997 |
| Jasd Ltd | Real estate | 2023 |
| Javis Manufacturing Company Limited | Wholesale & retail | 1963 |
| JAY Heads Ltd | Other services | 2018 |
| Jazapax Limited | Administrative & support | 1964 |
| JBL Engineering Services Ltd | Professional & scientific | 2022 |
| JC Communicate Ltd | Education | 2016 |
| JD Aviation Limited | Transport & logistics | 2004 |
| JDA Architectural Developments Limited | Professional & scientific | 2003 |
| JDT Motor Company Ltd | Wholesale & retail | 2007 |
| JEE Investments Ltd | Other services | 2025 |
| Jeepney Business Services Ltd | Administrative & support | 2005 |
| Jeff Davis Security Software Engineering Ltd. | Information & communication | 1995 |
| Jelia Limited | Real estate | 2006 |
| Jellybeans Play Centre Limited | Arts & recreation | 2007 |
| Jelp Cass Consulting Limited | Professional & scientific | 2017 |
| JEM Cleaning Limited | Administrative & support | 2006 |
| Jenny Hinds Limited | Professional & scientific | 2004 |
| Jerome Consultancy Limited T/As Censolutions (North East) Ltd | Professional & scientific | 2010 |
| Jesselle Limited | Real estate | 2003 |
| Jetcorner Limited | Households | 1987 |
| Jevari LLP | | 2025 |
| Jigsaw Telecommunications Limited | Financial services | 2008 |
| Jjls Construction Ltd | Construction | 2018 |
| JMC Electrical Services Ltd | Construction | 2022 |
| Jncden Limited | Health & social care | 2021 |
| JOE Davies (Manchester) Limited | Wholesale & retail | 1971 |
| JOE Winstanley Agri-Environment Advice Limited | Professional & scientific | 2007 |
| John C Killick and Associates Limited | Professional & scientific | 1991 |
| John Chorley & Company,Limited | Manufacturing | 1924 |