| Lifestyle Accommodation Limited | Households | 2019 |
| Lignum Campus Ltd | Real estate | 2021 |
| Lillypad Solutions Ltd | Construction | 2016 |
| Lime Kiln Farm Cottages Limited | Hospitality | 2009 |
| Lingfield Properties Limited | Construction | 1983 |
| Linkenholt Leisure Limited | Hospitality | 2004 |
| Linkmead Management Company Limited | Households | 2019 |
| Lisa Saunders Consultancy Ltd | Professional & scientific | 2024 |
| Lita Trading Limited | Wholesale & retail | 1995 |
| Little Loom Clothing Ltd | Wholesale & retail | 2025 |
| Litton Farms Ltd | Agriculture & fishing | 2025 |
| Litton Valley Developments Ltd | Construction | 2020 |
| Livewise Limited | Real estate | 2025 |
| LJ Wildy Ltd | Real estate | 2020 |
| LJT Professional Services Ltd | Administrative & support | 2019 |
| LMG Goods Ltd | Wholesale & retail | 2025 |
| Lockhart FOX Limited | Professional & scientific | 2012 |
| Lockleigh Building Limited | Construction | 2019 |
| Locomotive Entertainment Ltd | Information & communication | 2020 |
| Locum (SW) Limited | Health & social care | 2014 |
| Logical Transport Ltd | Transport & logistics | 2023 |
| London Rope Access Ltd | Construction | 2018 |
| Long Cross Stables Limited | Construction | 2003 |
| Long MAN Consulting Limited | Professional & scientific | 2026 |
| Longwoods Landscaping Ltd | Administrative & support | 2025 |
| Looking 4 Furniture Limited | Other services | 2011 |
| Lord Shaw Limited | Information & communication | 2010 |
| Loss Prevention Services Limited | Administrative & support | 2002 |
| Lotify Systems Ltd | Information & communication | 2026 |
| Lower Easton Solar C.I.C. | Energy | 2015 |
| LRA Group Ltd | Financial services | 2019 |
| LRA Moto Ltd | Wholesale & retail | 2025 |
| LT Technical Support Ltd | Wholesale & retail | 2018 |
| LTJ Roofing Ltd | Construction | 2024 |
| Lucas Kane Carpentry Limited | Construction | 2022 |
| Lucky Clover Bath Ltd | Real estate | 2021 |
| Luke Garrett Transport Ltd | Transport & logistics | 2016 |
| Lumeration Ltd | Professional & scientific | 2026 |
| Lumo Accountancy Ltd | Professional & scientific | 2026 |
| Luxlync Ltd | Wholesale & retail | 2026 |
| LYE Brothers Ltd | Manufacturing | 2018 |
| Lynfield Engineering Limited | Professional & scientific | 2002 |
| Lynrick Property Group Ltd | Real estate | 2025 |
| M Chiro Limited | Health & social care | 2017 |
| M Davidson Agencies Limited | Wholesale & retail | 2008 |
| M Lindley Limited | Other services | 2010 |
| M&M Property Masters Limited | Real estate | 2024 |
| M&R Products Ltd | Wholesale & retail | 2024 |
| M. G. Pumps Limited | Professional & scientific | 2005 |
| M.W.Plester Property Solutions Ltd | Construction | 2026 |
| Mabon + Sigvard Ltd | Real estate | 2025 |
| Mac'D and Loaded Ltd | Hospitality | 2026 |
| Macdonalds Limited | Real estate | 2008 |
| Maggie's Country Kitchen Limited | Manufacturing | 2002 |
| Maggs Properties Limited | Hospitality | 2007 |
| Magnetech Limited | Extraterritorial | 2023 |
| Mahadev Stores Limited | Wholesale & retail | 2013 |
| Maintenance South West Ltd | Construction | 2019 |
| Malone's Organics Ltd | Manufacturing | 2025 |
| Manik Software Limited | Information & communication | 2007 |
| Mannings Harlequin Ltd | Construction | 2012 |
| Manor Rose Heritage Plastering Ltd | Construction | 2026 |
| Manvers - Nash Limited | Real estate | 2002 |
| MAP Collection Ltd | Real estate | 2021 |
| Mararama Properties Ltd | Real estate | 2023 |
| Mareta Properties Limited | Real estate | 2022 |
| Mark Barrett Livestock Transport Ltd | Agriculture & fishing | 2021 |
| Mark Paterson Farms Limited | Agriculture & fishing | 2025 |
| Marronglade Limited | Real estate | 2013 |
| Marshall Airway Products Limited | Manufacturing | 2012 |
| Marsland Transport Limited | Transport & logistics | 2015 |
| Maspro Health Care Ltd | Health & social care | 2014 |
| Massey Wilcox (Holdings) Ltd | Financial services | 2022 |
| Massey Wilcox Transport Limited | Transport & logistics | 1976 |
| Massner Ltd | Wholesale & retail | 2017 |
| Master Food 1 Ltd | Hospitality | 2026 |
| Matt Bishop Real Estate Ltd | Real estate | 2025 |
| Matt Spanswick Heating Limited | Construction | 2020 |
| Matthew Higby and Company Limited | Manufacturing | 2002 |
| Matthews Investment Group Limited | Real estate | 2019 |
| Matvelo Limited | Real estate | 2023 |
| Maungakiekie Consulting Limited | Professional & scientific | 2016 |
| Maxem Glazing Ltd | Health & social care | 2010 |
| MBG Business Solutions Limited | Information & communication | 2017 |
| MBG Gold Limited | Construction | 2020 |
| MC Combat Limited | Arts & recreation | 2023 |
| Mcewan's Customs Limited | Wholesale & retail | 2020 |
| MCH Logistics Ltd | Transport & logistics | 2016 |
| Mcnally Ltd | Information & communication | 2014 |
| Mdjj Engineering and Supplies Ltd | Manufacturing | 2013 |
| Meadgate Breakdown Recovery Ltd | Transport & logistics | 2014 |
| Meadows Rural Ltd | Arts & recreation | 2025 |
| Mendip Auction Rooms Limited | Wholesale & retail | 2015 |
| Mendip Black Dog Limited | Wholesale & retail | 2018 |
| Mendip Construction Limited | Construction | 2016 |
| Mendip Dental Laboratory Limited | Health & social care | 2014 |
| Mendip Electrical Solutions Limited | Construction | 2018 |
| Mendip Energy Limited | Professional & scientific | 2010 |
| Mendip Gardens Management Limited | Households | 2012 |
| Mendip Home and Garden Services Ltd | Construction | 2022 |