| Jarmany Hill (Management Company) Limited | Households | 2023 |
| Jason Porthouse Limited | Information & communication | 2003 |
| JER Roofing and Construction Ltd | Construction | 2021 |
| Jhbodyworx Ltd | Wholesale & retail | 2026 |
| JO Friend Digital Limited | Information & communication | 2017 |
| Joggle Masonry Ltd | Manufacturing | 2016 |
| John Franklin Kitchens Limited | Manufacturing | 1997 |
| JON Flynn Design Ltd | Information & communication | 2013 |
| Josellaplace Limited | Construction | 1977 |
| JP Cleaning Ltd | Administrative & support | 2025 |
| JP Maintenance Limited | Construction | 2025 |
| JP Security Ltd | Administrative & support | 2025 |
| JP Services Ltd | Construction | 2025 |
| Julian Forsey Building and Restoration Limited | Construction | 2003 |
| Jungle Property (Somerset) Limited | Households | 2022 |
| Kairos Education Ltd | Education | 2007 |
| Kathy Contaris Limited | Health & social care | 2008 |
| Kelser Limited | Professional & scientific | 2003 |
| Keward (Management) Limited | Real estate | 2013 |
| Kinberry Limited | Professional & scientific | 2005 |
| Kinetica Museum Limited | Arts & recreation | 2004 |
| Kingswood Construction Carpentry & Building Ltd | Manufacturing | 2022 |
| Kippler Consulting Limited | Information & communication | 2018 |
| KM Premier Property & Sports Services Limited | Construction | 2026 |
| Knapp Farm Limited | Agriculture & fishing | 2002 |
| Knight's Fish Restaurant 2010 Limited | Hospitality | 2013 |
| Know Your Vibration Ltd | Other services | 2023 |
| KRA Studio Ltd | Manufacturing | 2025 |
| KSM Online Limited | Information & communication | 2009 |
| Kubi MAY Crafts Limited | Wholesale & retail | 2026 |
| Kundalini Limited | Real estate | 2013 |
| Kydo Nutrition Ltd | Information & communication | 2025 |
| L & V Contract Carpenters Limited | Manufacturing | 2003 |
| L J Electrical (South West) Ltd | Construction | 2020 |
| L Kent Electrical Ltd | Construction | 2025 |
| Labyrinth Books Limited | Wholesale & retail | 2025 |
| Lakota Fields CIC | Other services | 2018 |
| Laneale Design Ltd | Professional & scientific | 2007 |
| Lavender Court (Street) Management Company Limited | Households | 1988 |
| Legend Recruitment Limited | Administrative & support | 2016 |
| Leoma Holdings Ltd | Professional & scientific | 2014 |
| Leovida Ltd | Wholesale & retail | 2022 |
| LG Developments Limited | Administrative & support | 2013 |
| Lifeinoneplace Ltd | Other services | 2015 |
| Light Solution Limited | Administrative & support | 2008 |
| Liminal Studios Ltd | Information & communication | 2026 |
| Lincoln House Limited | Wholesale & retail | 1996 |
| Lintells Garage Limited | Wholesale & retail | 2010 |
| Lions Live Here Ltd | Information & communication | 2025 |
| Little Imps Limited | Wholesale & retail | 2008 |
| Littleimps.Co.Uk LLP | | 2009 |
| Living Water Exercises | Other services | 2023 |
| Ljck Ltd | Professional & scientific | 2023 |
| Llamapress Ltd | Information & communication | 2014 |
| Lloyds Datum Limited | Construction | 2002 |
| Locks, Door and Window Fittings Ltd | Manufacturing | 2013 |
| Lomax DB Limited | Construction | 2026 |
| Lomax Design and Build Limited | Construction | 2014 |
| Lomax Equipment Limited | Administrative & support | 2026 |
| Lost Projectz CIC | Information & communication | 2023 |
| Louis’ Butchers Limited | Wholesale & retail | 2022 |
| LSE Oxford Contractors Ltd | Construction | 2018 |
| Lubborn Associates Limited | Real estate | 2020 |
| Lucubra Limited | Professional & scientific | 2006 |
| Luna Media Production Ltd | Information & communication | 2025 |
| Luskentyre Capital Ltd | Financial services | 2025 |
| LUX Tanning Studio Ltd | Other services | 2025 |
| Lyra Retreats Ltd | Information & communication | 2024 |
| M W Masonry Ltd | Construction | 2018 |
| M.J.P. Group Ltd | Administrative & support | 2016 |
| Madysen Limited | Information & communication | 2012 |
| Magdalene Wellness Centre Limited | Wholesale & retail | 2025 |
| Maidencroft Property Holdings Limited | Extraterritorial | 2016 |
| Maidencroft Property Limited | Administrative & support | 1970 |
| Mainswitch Limited | Hospitality | 2005 |
| Maltex Ltd | Information & communication | 2014 |
| MAN Myth & Magik Limited | Wholesale & retail | 2005 |
| Managed Connected Objects Ltd | Professional & scientific | 2020 |
| Mandorla Therapies and Training Ltd | Health & social care | 2017 |
| Mapstone Farms Limited | Agriculture & fishing | 2017 |
| Marie Burke Art Limited | Arts & recreation | 2019 |
| Marina Barcenilla Parfums Ltd | Manufacturing | 2021 |
| Martins Field Management Company Limited | Real estate | 2014 |
| Mathana Consulting Ltd | Information & communication | 2024 |
| Matt Martin Guitars Ltd | Manufacturing | 2023 |
| Maureen Allin Residential Management Services Ltd | Real estate | 1996 |
| Mauriana Ltd | Real estate | 2014 |
| Mayakara Ltd | Professional & scientific | 2011 |
| Maythorne Trees & Woodlands Limited | Agriculture & fishing | 2025 |
| Mbnk Investments Ltd | Real estate | 2025 |
| Mccallion Building Company Ltd | Construction | 2024 |
| Mckinven's Kitchen Ltd | Hospitality | 2022 |
| Mcnulty Lyons Ltd | Construction | 2014 |
| MDG Build Limited | Construction | 2017 |
| Medfitpro Ltd | Health & social care | 2020 |
| Melhuish & Saunders Holdings Limited | Professional & scientific | 2016 |
| Melhuish & Saunders Limited | Construction | 1992 |
| Middleton Engineering Limited | Manufacturing | 1985 |
| Millard's Build Limited | Construction | 2026 |
| Millard's Studio Limited | Professional & scientific | 2026 |