| LE Solar 2 Limited | Administrative & support | 2023 |
| LE Solar 3 Limited | Administrative & support | 2023 |
| LE Solar 4 Limited | Administrative & support | 2023 |
| LE Solar 5 Limited | Administrative & support | 2023 |
| LE Solar 6 Limited | Administrative & support | 2025 |
| Leadership Challenges International C.I.C. | Arts & recreation | 2016 |
| Leadership Connect Solutions Ltd | Professional & scientific | 2023 |
| Leafield Environmental Holdings Limited | Financial services | 2010 |
| Leafield Environmental Limited | Manufacturing | 2010 |
| Lean Lines UK Limited | Professional & scientific | 2017 |
| Lemiss Limited | Information & communication | 2025 |
| Lime Legal Limited | Information & communication | 2004 |
| Lime Tree Place Management Company NO.1 Limited | Households | 2000 |
| Lime Tree Place Management Company NO.2 Limited | Households | 2000 |
| Liminal Space Consulting Ltd | Other services | 2024 |
| Linarey Ltd | Professional & scientific | 2021 |
| Linarey Property Holdings Limited | Real estate | 2022 |
| Lindens Court Management Company (NO.1) Limited | Households | 1984 |
| Lindens Court Management Company (NO.3) Limited | Households | 1986 |
| Lister Lift Trucks Limited | Wholesale & retail | 2007 |
| Little OWL Solutions Limited | Information & communication | 2021 |
| Littlechild Holdings Ltd | Financial services | 2024 |
| Lizziejaynes Beauty and Wellness Clinic Ltd | Other services | 2024 |
| Locoda Properties Ltd | Real estate | 2024 |
| Logjam Technologies Ltd | Extraterritorial | 2020 |
| Longacre (Bath) Management Limited | Households | 2014 |
| Longford Manufacturing & Coach Building Co Limited(The) | Extraterritorial | 1947 |
| Lords and Lads Limited | Other services | 2014 |
| Louarch Limited | Real estate | 2025 |
| Lowden Garden Centre Limited | Agriculture & fishing | 2004 |
| LP1 Holdings Limited | Real estate | 2025 |
| Lucas Grinding Limited | | 1986 |
| Lucent Alpha Centauri Limited | Construction | 2023 |
| Lucent Halo Limited | Real estate | 2023 |
| Lucent Horizon Limited | Real estate | 2023 |
| Lucent Investments Limited | Real estate | 2023 |
| Lucent Moon Limited | Construction | 2023 |
| Lucent Nova Limited | Construction | 2023 |
| Lucent Orbit Limited | Construction | 2023 |
| Lucky 7 Recruitment Ltd | Administrative & support | 2015 |
| Lucyna Skrzypczak Ltd | Professional & scientific | 2024 |
| Luminous Energy (CM) Limited | Energy | 2025 |
| Luminous Energy (EF) Limited | Energy | 2016 |
| Luminous Energy (TN) Ltd | Administrative & support | 2020 |
| Luminous Energy Asset Management Limited | Professional & scientific | 2023 |
| Luminous Energy Development Limited | Professional & scientific | 2023 |
| Luminous Energy Generation Limited | Energy | 2023 |
| Luminous Energy Group Limited | Financial services | 2013 |
| Luminous Energy UK Limited | Energy | 2023 |
| Lynwood (Bath) Management Company Limited | Households | 1983 |
| M G & G Holdings Limited | Real estate | 2022 |
| M G & G Lettings Limited | Real estate | 2023 |
| M J Johnston Consulting Ltd | Information & communication | 2022 |
| Madaflavours Ltd | Wholesale & retail | 2020 |
| Makebelieve Arts | Arts & recreation | 2004 |
| Maldives by Olivia Ltd | Administrative & support | 2026 |
| Manmade Media Ltd | Information & communication | 2024 |
| Mansion Mews Management Limited | Households | 2002 |
| Manupackaging U.K. Ltd | Manufacturing | 1992 |
| Maria Christina Limited | Other services | 2003 |
| Marin Mountain Bikes UK Ltd | Wholesale & retail | 2019 |
| Mark Garrett Tax and Accountancy Ltd | Professional & scientific | 2009 |
| Mark Griffiths Creative Limited | Professional & scientific | 2011 |
| Markconsulting Limited | Administrative & support | 2025 |
| Marlaywade Limited | Professional & scientific | 2018 |
| Marshalswick Farm Estate (RTM Company) Limited | Households | 2013 |
| Martyn COX Advanced Caring Dentistry Limited | Health & social care | 2008 |
| Massey & Co Holdings Ltd | Hospitality | 2025 |
| Matcham Property Investments Limited | Real estate | 2013 |
| Matthew Clay Architects Ltd | Professional & scientific | 2012 |
| Maximum Mileage Coaching Ltd | Education | 2025 |
| Maya Studio Limited | Administrative & support | 2004 |
| Mayne Property Ltd | Real estate | 2024 |
| Mayne Property Solutions Limited | Real estate | 2015 |
| Mayne Solutions Limited | Financial services | 2010 |
| Mckenzie Consultants Ltd | Professional & scientific | 2018 |
| Meadow View Bath (Management) Company Limited | Households | 1994 |
| Mediawan Limited | Manufacturing | 2009 |
| Medicamentum Ltd | Education | 2022 |
| Medivys Ltd | Information & communication | 2024 |
| Megcourt One Limited | Households | 1988 |
| Melksham Tennis Club Limited | Arts & recreation | 2025 |
| Menemsha Limited | Administrative & support | 2001 |
| Menzies Cameron Limited | Professional & scientific | 2003 |
| MF Consulting Ltd | Professional & scientific | 2020 |
| MG Plumb Ltd | Construction | 2018 |
| Mian Bashir Insaniyat Appeal | Health & social care | 2015 |
| Mian Bashir Limited | Real estate | 2022 |
| Millard Signs Limited | Professional & scientific | 1997 |
| Millenium Court (Management) Limited | Households | 2013 |
| Miller Estate Services Limited | Real estate | 2004 |
| Milsom Apartments Management Limited | Households | 2019 |
| Mindful Clinic Ltd | Health & social care | 2024 |
| Minerva Advisers Ltd | Professional & scientific | 2025 |
| Minerva Furniture Group Limited | Other services | 1992 |
| Minimo Ltd | Administrative & support | 2026 |
| Mjaro Trading Ltd | Wholesale & retail | 2026 |
| MJC Contracting Solutions Limited | Information & communication | 2017 |
| Mk&Ay Limited | Arts & recreation | 2025 |
| Mnexp Limited | Transport & logistics | 2022 |