| Jonah JAY Architects Limited | Professional & scientific | 2018 |
| Jones Orthopaedics Ltd | Health & social care | 2020 |
| Joss Limited | Arts & recreation | 2002 |
| Joss Publishing Limited | Arts & recreation | 2004 |
| JP Agri Limited | Agriculture & fishing | 2012 |
| JRW Accountancy Services Ltd | Professional & scientific | 2020 |
| JS Tour LLP | | 2026 |
| JSS Mechanicals Limited | Wholesale & retail | 2025 |
| Just BE Holistic Therapy Limited | Health & social care | 2026 |
| JWS Poultry Services Ltd | Agriculture & fishing | 2015 |
| K and S Autosales Ltd | Wholesale & retail | 2024 |
| K&K Eden Ltd | Financial services | 2024 |
| K.S Growth Academy Ltd | Education | 2025 |
| Katie Steed Ltd | Information & communication | 2018 |
| KCL Consultancy Limited | Professional & scientific | 2023 |
| KDP Consulting Ltd | Professional & scientific | 2024 |
| Kentisbeare Village Stores 2017 Limited | Wholesale & retail | 2016 |
| Kerstans Cleaning Ltd | Administrative & support | 2026 |
| Kerswell Barns Management Company Limited | Households | 2017 |
| Keystone Construction Southwest Limited | Construction | 2025 |
| Kingswood Company Group Limited | Construction | 2019 |
| Kingwood Children Ltd | Health & social care | 2019 |
| KLM Developers Ltd | Construction | 2025 |
| Kolors Decorating Limited | Construction | 2021 |
| KOR Consultancy Limited | Construction | 2009 |
| Kpack (UK) Limited | Wholesale & retail | 2003 |
| KS Hardy Consultancy Limited | Professional & scientific | 2015 |
| KWG Property Investment Ltd | Real estate | 2025 |
| KWR Insight & Consulting Ltd | Professional & scientific | 2023 |
| L Adams Tree Services Limited | Agriculture & fishing | 2026 |
| LA Vache Rouge Limited | Administrative & support | 2015 |
| Lane END Medical Limited | Health & social care | 2026 |
| Last Course Patisserie Limited | Manufacturing | 2002 |
| Lats Hire Limited | Administrative & support | 2026 |
| Laureb Ltd | Professional & scientific | 2021 |
| Lead Media Ltd | Information & communication | 2012 |
| LEE Mcardle Properties Ltd | Real estate | 2024 |
| Leelashop Ltd | Wholesale & retail | 2024 |
| Leelashop ST Ives Ltd | Wholesale & retail | 2026 |
| Light Fantastic Ltd | Professional & scientific | 2026 |
| Lightwater Accountants Limited | Professional & scientific | 2015 |
| Lion and Fiddle Limited | Construction | 2026 |
| Littlewell Financial Management Limited | Financial services | 2014 |
| Little’S Coffee Ltd | Manufacturing | 1995 |
| London Basin Company Ltd | Wholesale & retail | 2013 |
| Lottie Dainton Limited | Information & communication | 2018 |
| Lovedays Limited | Professional & scientific | 2014 |
| LP Construction SW Ltd | Manufacturing | 2012 |
| LRT Sporting Ltd | Arts & recreation | 2026 |
| Lucas Injectors Limited | Manufacturing | 2020 |
| Luxuria Assets Limited | Financial services | 2025 |
| Luxuria Beechwood Limited | Real estate | 2025 |
| Luxuria Bespoke Limited | Professional & scientific | 2025 |
| Luxuria Developments Limited | Construction | 2015 |
| Lyme Bay Dived Scallops Limited | Agriculture & fishing | 2024 |
| M Baker Engineering Limited | Manufacturing | 2009 |
| M&D Car Sales Ltd | Wholesale & retail | 2020 |
| MAC Consulting Ltd | Professional & scientific | 2022 |
| MAC Macartney Ltd | Professional & scientific | 2017 |
| MAJ Property Services Limited | Real estate | 2016 |
| Man-In-A-Hat Limited | Arts & recreation | 2012 |
| Manning & Kerr Ltd | Wholesale & retail | 2017 |
| Mark DM Hammond Ltd | Information & communication | 2023 |
| Market Sheds Catering Ltd | Hospitality | 2022 |
| Marosi Limited | Wholesale & retail | 2024 |
| Marples Milk Partnership LLP | | 2024 |
| Marples Property Partnership LLP | | 2024 |
| Martin Technical Solutions Ltd | Information & communication | 2015 |
| Mask Control Systems Limited | Manufacturing | 2013 |
| Matt Horler Agricultural Engineering Limited | Manufacturing | 2020 |
| Maximus Software Ltd | Information & communication | 2010 |
| Mayfield Consulting Limited | Professional & scientific | 1998 |
| MB Electrical (South West) Limited | Construction | 2019 |
| MC & RL Properties Ltd | Real estate | 2022 |
| Mcguin Optix Ltd | Construction | 2025 |
| Meadow Plant Ltd | Wholesale & retail | 2026 |
| Meakers Developments Ltd | Construction | 2017 |
| Med-Ex Financial Advisory Services Limited | Financial services | 2002 |
| Medicare Colgate Limited | Wholesale & retail | 1994 |
| Medicus Data Ltd | Information & communication | 2017 |
| Meenagrave Contracts Ltd | Construction | 2023 |
| Mellow Grove Ltd | Agriculture & fishing | 2013 |
| Mepology Ltd | Professional & scientific | 2026 |
| Mercari International Ltd | Administrative & support | 2015 |
| Metcalfe Allen Limited | Construction | 2000 |
| Mharag Ltd | Hospitality | 2025 |
| Michael Milne Wealth Management Limited | Financial services | 2009 |
| Middevon Digital Limited | Professional & scientific | 2025 |
| Migolf Dartington Ltd | Wholesale & retail | 2025 |
| Mill Leat House RTM Company Limited | Professional & scientific | 2008 |
| Mini & Barn Ltd | Health & social care | 2021 |
| Ministry of Play Limited | Arts & recreation | 2016 |
| Mister P Ltd | Real estate | 2022 |
| Mitchem Brothers Limited | Agriculture & fishing | 2003 |
| Mitran Express Ltd | Transport & logistics | 2025 |
| MJB Power Solutions Ltd | Construction | 2025 |
| MJG Engineering Ltd | Manufacturing | 2025 |
| MJH Planning Services Ltd | Construction | 2009 |
| MLE PUB Ltd | Hospitality | 2025 |
| MLE Taunton Limited | Financial services | 2020 |