| Hugo Street Management Limited | Households | 1994 |
| I C B Consultancy Limited | Professional & scientific | 2008 |
| I. & P.Lifting Gear Limited | Wholesale & retail | 1967 |
| I.P.S. (Co-Ordinated Building Services) Limited | | 1981 |
| ICS Media Limited | Professional & scientific | 2009 |
| Ideal Standard (UK) Pension Trustees Limited | Manufacturing | 2001 |
| IGO (Europe) Limited | Professional & scientific | 2005 |
| IGS Investments Ltd | Information & communication | 2024 |
| Implementing Cad/Cam Limited | Professional & scientific | 2004 |
| IMT Solutions Limited | Professional & scientific | 2003 |
| IN the Wild Escapes Ltd | Hospitality | 2023 |
| Indigo Elite Divers Ltd | Other services | 2022 |
| Industrial Electronics Limited | Administrative & support | 1985 |
| Ingenious Music Publishing Ltd | Information & communication | 2018 |
| Ingenium Systems Ltd | Construction | 2025 |
| Iniveo Limited | Manufacturing | 2004 |
| Innovative Development Solutions Limited | Professional & scientific | 2005 |
| Inspirate Lifestyles Ltd | Arts & recreation | 2022 |
| Iris & Belles Ltd | Wholesale & retail | 2017 |
| Isabellakate Limited | Information & communication | 2021 |
| Istanbul Barbers Shop Ltd | Other services | 2025 |
| IVT Accountancy Limited | Professional & scientific | 2002 |
| J & D Roofing Services Ltd | Construction | 2006 |
| J & J Plastering Limited | Construction | 2002 |
| J Cowan Construction Services Limited | Construction | 2003 |
| J F Kehoe Installations Ltd | Manufacturing | 2002 |
| J Mosedale Properties Limited | Real estate | 2004 |
| J. C. Bamford Investments | Professional & scientific | 1984 |
| J. C. Bamford Limited | Professional & scientific | 2004 |
| J. Taberner Plant Hire Limited | Agriculture & fishing | 1976 |
| J.C.B. Earthmovers Limited | Manufacturing | 1968 |
| J.H. Fenner & Co. Limited | Manufacturing | 1953 |
| J.L.Black (Good Clothes) Limited | Wholesale & retail | 1953 |
| J.Owen Jones & Sons Limited | Extraterritorial | 1963 |
| J.R.Gilman & SON Limited | Agriculture & fishing | 1964 |
| James Bulmer Limited | Construction | 2007 |
| James Dawson & Son,Limited | Manufacturing | 1896 |
| Janus (1762) Limited | Hospitality | 2000 |
| Jayco Limited | Manufacturing | 2002 |
| JCB Accounting and Systems Ltd | Professional & scientific | 1999 |
| JCB Advisory Limited | Professional & scientific | 2024 |
| JCB Benelux Ltd | Professional & scientific | 1997 |
| JCB CAB Systems Limited | Manufacturing | 1975 |
| JCB Farms Limited | Agriculture & fishing | 1964 |
| JCB Heavy Products Ltd | Manufacturing | 1990 |
| JCB Insurance Services Limited | Financial services | 1984 |
| JCB Landpower Ltd. | Manufacturing | 1988 |
| JCB Management Services | Professional & scientific | 1979 |
| JCB Mini Excavators Limited | Professional & scientific | 1980 |
| JCB Nano Technology Limited | Professional & scientific | 2004 |
| JCB Remarketing Limited | Wholesale & retail | 2005 |
| JCB Sitewear Limited | Professional & scientific | 1975 |
| JCB Transmissions | Manufacturing | 1984 |
| JDH Financial Guidance Ltd | Financial services | 2000 |
| Jela Health Consultancy Services Ltd | Administrative & support | 2021 |
| Jellybean Commercial Limited | Administrative & support | 2021 |
| Jelusevic Technical Services Ltd. | Professional & scientific | 1997 |
| Jenny's Dog Grooming Limited | Other services | 1999 |
| Jessamin Limited | Other services | 2001 |
| Jobsagoodun Limited | Information & communication | 2004 |
| John Dallow Contracts Limited | Administrative & support | 2004 |
| John F. Owen & Company Limited | Extraterritorial | 2000 |
| John Joseph (Midlands) Limited | Real estate | 1964 |
| Johnsons the Florists Limited | Wholesale & retail | 2002 |
| JON Sarsfield Limited | Professional & scientific | 2005 |
| JPG Cars Limited | Wholesale & retail | 2006 |
| JPR Mechanical and Electrical Services Limited | Construction | 1972 |
| JSW Printservice Limited | Manufacturing | 1999 |
| JY Services Limited | Professional & scientific | 2007 |
| K & J O'Sullivan Limited | Other services | 2003 |
| K & S (Nominees) Limited | Extraterritorial | 1994 |
| K & S Directors Limited | Extraterritorial | 1993 |
| K & S Secretaries Limited | Extraterritorial | 1993 |
| K G Collier Limited | Transport & logistics | 2002 |
| K.J. & M. Rogers Limited | Construction | 2002 |
| K.J.Ledgar Ltd. | Real estate | 2003 |
| K.M.N. Commission Agents Limited | Households | 1976 |
| K2 Logistics Limited | Transport & logistics | 2006 |
| Karisto Limited | Information & communication | 1999 |
| Kegwatch Limited | Administrative & support | 2000 |
| Kenblo (Domestic Appliances) Limited | | 1967 |
| Kerrygold Fresh Foods Limited | Professional & scientific | 1985 |
| Kershaw Properties Ltd | Real estate | 2005 |
| Key Precision Limited | Manufacturing | 2004 |
| KG Jones Floor Screeding Specialists Limited | Construction | 2004 |
| Kgms Properties Limited | Real estate | 1995 |
| Kisnet Limited | Wholesale & retail | 2007 |
| Knights Professional Services Limited | Professional & scientific | 2013 |
| KWG Developments Limited | Financial services | 2021 |
| L & L Dillon Limited | Wholesale & retail | 2007 |
| L a Berkshire Associates Limited | Arts & recreation | 1999 |
| L.A. Air Conditioning Solutions Limited | Construction | 2006 |
| L.A. Fencing Contractors Limited | Construction | 2003 |
| L.K.M. Furniture | | 1993 |
| LA Casa Vecchia Limited | Real estate | 1999 |
| LAI Retail Limited | Administrative & support | 2006 |
| Landywood Contract Services Limited | Other services | 2002 |
| LAS Solutions Limited | Information & communication | 1998 |
| Latham International Limited | Manufacturing | 1988 |
| LCI Designs Limited | Information & communication | 2004 |