| J.O.M Property Ltd | Real estate | 2023 |
| J.P.Matthews Limited | Agriculture & fishing | 1961 |
| J.T.S. Snack Foods Limited | Wholesale & retail | 1992 |
| Jackson Machinery Services Limited | Administrative & support | 2000 |
| James & Associates Financial Services Limited | Financial services | 2002 |
| James Bryan Security Services Ltd | Administrative & support | 2021 |
| James Gaunt Interiors Limited | Wholesale & retail | 2002 |
| Jaxcharm Limited | Arts & recreation | 1980 |
| JCH Holdings Limited | Financial services | 2018 |
| JDH Design & Media Ltd | Information & communication | 2017 |
| Jesterworld Computers Limited | Professional & scientific | 2003 |
| Jhconsulting Architects Limited | Professional & scientific | 2003 |
| JJD Norfolk Limited | Hospitality | 2023 |
| JMD Design Limited | Professional & scientific | 1999 |
| John Tucker & SON Limited | Administrative & support | 2007 |
| John YEO Limited | Manufacturing | 2005 |
| Johnson Elevanja Limited | Manufacturing | 1992 |
| Jonathan Lynne Limited | Manufacturing | 1983 |
| Jordan Sanitaire Limited | Extraterritorial | 2014 |
| Joseph Casson Estate Agency Limited | Real estate | 2017 |
| JSS (Taunton) Limited | Real estate | 2001 |
| Jual Branded Clothing and Promotions Limited | Administrative & support | 2003 |
| JW & TJ Pearce Limited | Manufacturing | 2012 |
| K & M Electrical Contractors Limited | Construction | 2005 |
| K Shoemakers Limited | Manufacturing | 1935 |
| K Shoes Contributory Pension Scheme (Trustees) Limited | Professional & scientific | 1987 |
| K. Shoes Limited | Manufacturing | 1949 |
| K3 Services Ltd | Administrative & support | 2017 |
| Kc&Aw Limited | Real estate | 2007 |
| Kedgeworth 2000 Ltd | Manufacturing | 1999 |
| Kellands (Holdings) Limited | Professional & scientific | 1947 |
| Kellands (Plant Sales) Limited | Wholesale & retail | 1950 |
| Kemp Hall Limited | Professional & scientific | 2007 |
| Kengfast Limited | Wholesale & retail | 1981 |
| Kenny Construction Limited | Extraterritorial | 1963 |
| Kenwood Chef Restore Limited | Wholesale & retail | 2015 |
| Kerne Holdings (1962) Limited | Real estate | 1962 |
| Kevbuy Limited | Wholesale & retail | 2006 |
| Kevin Corcoran Carpets and Vinyls Limited | Wholesale & retail | 2003 |
| Key Finish Plastering and Drylining Limited | Construction | 2015 |
| Keyford Development Limited | Extraterritorial | 2002 |
| Kingsmead Business Park Management Company Limited | Real estate | 2007 |
| Kingsnoll Limited | Construction | 2003 |
| Kingston Farm Leisure Ltd | Professional & scientific | 2013 |
| Kingsway Investments (Frome) Limited | Construction | 2004 |
| Kismet House Care Home Limited | Health & social care | 2006 |
| Knight Electrical Limited | Manufacturing | 1999 |
| Koreesa Medical Solutions Laboratory Co., Ltd | Extraterritorial | 2020 |
| L & M Wisbech Food Ltd | Wholesale & retail | 2026 |
| L and W Investments Limited | Real estate | 2001 |
| LA Benzina Limited | Wholesale & retail | 2007 |
| Laceys Yeovil Limited | Real estate | 2003 |
| Lakegold Limited | Hospitality | 1989 |
| Lakeside Lifting Limited | Manufacturing | 2005 |
| Lambridge House Bath (Management) Company Limited | Administrative & support | 1996 |
| Lancelot Windows & Conservatories Limited | Construction | 2007 |
| Lang Plant Limited | Administrative & support | 2007 |
| Langford Lakes Security Systems Limited | Administrative & support | 2005 |
| Langford Properties Limited | Real estate | 1991 |
| Laura Cooke Limited | Administrative & support | 2016 |
| Lcng Ltd | Professional & scientific | 2002 |
| Lean Games Limited | Wholesale & retail | 2006 |
| Lees Building Contractors Limited | Construction | 2004 |
| LEN Carter Construction Limited | Wholesale & retail | 1989 |
| Leviathan Trading Company Limited | | 1987 |
| Lilycombe Ltd | Real estate | 2025 |
| Linen Yard Investments (Crewkerne) Ltd | Real estate | 1971 |
| Little Crow Renewables Limited | Energy | 2018 |
| Little Fish (Bristol) Limited | Arts & recreation | 2006 |
| Livefood UK Limited | Agriculture & fishing | 2003 |
| Lobley Haulage Limited | Transport & logistics | 2005 |
| Lobsgrove Park Developments Limited | Real estate | 2006 |
| Logo Golf Balls Limited | Wholesale & retail | 2005 |
| Lomville Limited | Information & communication | 1997 |
| LOW Autobodies Limited | Wholesale & retail | 2018 |
| Luke Grafton Stonemason Limited | Construction | 2003 |
| M D L Creative Crowns Limited | Health & social care | 2005 |
| M.S.W. Building Services Limited | Construction | 2007 |
| M5 Textiles Limited | Wholesale & retail | 2002 |
| MAA Construction Limited | Construction | 2003 |
| Magdalene Court (Taunton) Limited | Real estate | 2000 |
| Maltin Pollution Control Systems (1967) Ltd | Water & waste | 1987 |
| Managed Care Ltd | Health & social care | 1999 |
| Management Beyond Design Limited | Administrative & support | 2020 |
| Manufacturers Marketing Limited | | 1984 |
| Marcombe Valley Farms Limited | Agriculture & fishing | 1979 |
| Mariners Court (Bridgwater) Management Company Limited | Real estate | 1989 |
| Marion Milne Productions Limited | Information & communication | 2007 |
| Marsh Lane Day Nursery Limited | Education | 2002 |
| Marshall James Garden Development Limited | Administrative & support | 2002 |
| Martock Commercials Limited | Wholesale & retail | 2007 |
| Mayfair Business & Tax Consultancy Limited | Professional & scientific | 2009 |
| MB Avionics Ltd | Manufacturing | 2018 |
| MBH Industrial Services Limited | Construction | 1994 |
| MCA Coaching Limited | Administrative & support | 2019 |
| Mckie & Co LLP | | 2001 |
| Mcmanus Building Contractors Limited | Construction | 2003 |
| ME Robot Limited | Information & communication | 2017 |
| Meadside Developments (Caldicot) Ltd | Construction | 2007 |
| Meadside Developments (Rooksbridge) Ltd | Construction | 2007 |