| Leaford Energy Limited | Energy | 2024 |
| Leargas Consulting Ltd | Administrative & support | 2023 |
| Learn 2 Play Online.Com Ltd. | Education | 2020 |
| LEE Project Management Limited | Professional & scientific | 2025 |
| Leestone Consultancy Limited | Professional & scientific | 2025 |
| Leewood Recycling Ltd | Water & waste | 2022 |
| Lefrere Limited | Professional & scientific | 2021 |
| Legacych Ltd | Construction | 2025 |
| Lendrums Bridge Energy Limited | Energy | 2024 |
| LF Holdings Ltd | Financial services | 2019 |
| Liberty Home Solutions Ltd | Construction | 2021 |
| Lifebell Limited | Administrative & support | 2019 |
| Liifa Developments Ltd | Real estate | 2024 |
| Lilburn Properties Limited | Real estate | 2018 |
| Lime Jelly Project Management Limited | Professional & scientific | 2014 |
| Lingwood Creative Solutions Limited | Administrative & support | 2022 |
| Lisa Anderson Media Limited | Information & communication | 2011 |
| Little Furze Apartment Block 1 Residents Management Company Limited | Households | 2026 |
| Little Furze Apartment Block 2 Residents Management Company Limited | Households | 2026 |
| Little Furze Resident Management Company Limited | Households | 2024 |
| Little Windmill Hill Residents Association Limited(The) | Households | 1986 |
| Live Retail Ltd | Wholesale & retail | 2023 |
| Live Site Learning CIC | Construction | 2019 |
| Live Site Ltd | Construction | 2017 |
| Llanbrynmair Energy Limited | Energy | 2024 |
| Llanerfyl Access Road Consortium Limited | Administrative & support | 2007 |
| Llynfi Afan Renewable Energy Park Limited | Administrative & support | 2006 |
| Loben Aviation Limited | Professional & scientific | 2021 |
| Lodge Consulting Limited | Information & communication | 2014 |
| Logan Graham LLP | | 2014 |
| Logik Developments (Arundel Street) Limited | Real estate | 2016 |
| Logocentric Ltd | Manufacturing | 2019 |
| London Fluid System Technologies Limited | Wholesale & retail | 2024 |
| London Health Ltd | Health & social care | 2018 |
| Longhedge Holdings Limited | Financial services | 2025 |
| Longhedge Solar Limited | Energy | 2022 |
| Loscar Limited | Energy | 2011 |
| LPB Land Developments Ltd | Construction | 2020 |
| LTF Property Ltd | Real estate | 2021 |
| Lumar Consulting Limited | Information & communication | 2015 |
| Luméa Clinic Ltd | Health & social care | 2025 |
| Lynch Financial Consulting Limited | Professional & scientific | 2025 |
| Lynx Aeronautical Recruitment Ltd | Administrative & support | 2022 |
| M F Polar Sales Limited | Manufacturing | 2013 |
| M Tanner & Sons Ltd | Construction | 2018 |
| M Thomas Ltd | Real estate | 2025 |
| M.Jewell Services Ltd | Construction | 2019 |
| Machaire Energy Storage Limited | Energy | 2024 |
| Macrail Systems Ltd | Information & communication | 2001 |
| Mahoney Developments (the Avenue) Ltd | Real estate | 2019 |
| Maid Easy Limited | Administrative & support | 2008 |
| Makou Endurance Ltd | Arts & recreation | 2025 |
| Malax Investments Limited | Professional & scientific | 1999 |
| Malpin LLP | | 2013 |
| Malpujan Ltd | Real estate | 2016 |
| Manor Farm Solar Limited | Energy | 2011 |
| Manor Surveying, Civil Engineering & Groundworks Ltd | Construction | 2023 |
| Marbhp Limited | Wholesale & retail | 2012 |
| Marine Payroll Services Limited | Extraterritorial | 2020 |
| Mark Avionics Ltd | Information & communication | 2014 |
| Market Boosters Ltd | Professional & scientific | 2018 |
| Markholwell Ltd | Professional & scientific | 2022 |
| Marlin Consulting Group Ltd | Professional & scientific | 2018 |
| Marlowe Digital Ltd | Other services | 1995 |
| Marlowe Digital Properties Limited | Extraterritorial | 2009 |
| Marlowe Graphic Sales Limited | Extraterritorial | 2002 |
| Marshall & SON Carpentry Limited | Construction | 2017 |
| Marshtek Ltd | Information & communication | 2023 |
| Martial Hub Ltd | Real estate | 2019 |
| Massa Motors Ltd | Wholesale & retail | 2015 |
| Matrix Kitchens Ltd | Professional & scientific | 2024 |
| Maverick Business Support Ltd | Administrative & support | 2026 |
| MAX Protect Ltd | Wholesale & retail | 2011 |
| Maxx Services Limited | Construction | 2017 |
| MC Alpine Enterprises Limited | Extraterritorial | 2003 |
| MC Power Limited | Energy | 2011 |
| Mcalpine Educational Endowments Limited(The) | Administrative & support | 1957 |
| Mcaulay Holdings Limited | Financial services | 2020 |
| Mcdonald Property Services Limited | Hospitality | 2012 |
| MCL Associates Ltd | Administrative & support | 2023 |
| Mcloughlin & Cross Ltd | Hospitality | 2024 |
| Mcmullan Construction Limited | Construction | 2017 |
| MCV Investments Limited | Administrative & support | 2003 |
| MCV Limited | Financial services | 2004 |
| MDD Corporate Solutions Limited | Administrative & support | 2014 |
| Mdsal Ltd | Construction | 2022 |
| Meab Ltd | Wholesale & retail | 2022 |
| Mediqam Ltd. | Health & social care | 2022 |
| Medit Education Limited | Education | 2018 |
| Medox Tutors Limited | Education | 2015 |
| Mendennick Solar Limited | Energy | 2014 |
| Merchant Savings Solutions Ltd | Financial services | 2021 |
| MESH4 Ltd | Wholesale & retail | 1997 |
| MH ALI & Associates Ltd | Professional & scientific | 2025 |
| Miami Motors Limited | Wholesale & retail | 1998 |
| Michelle Martin Architectural Design (Mmad) Ltd | Professional & scientific | 2017 |
| Middle Oak Developments Limited | Construction | 2024 |
| Mikemotors Limited | Wholesale & retail | 2025 |
| Milltown Homes (Southern) Limited | Construction | 2013 |
| Milro Ltd | Construction | 2022 |