| Lumina Metals and Energy Ltd | Energy | 2025 |
| Luminex Power Limited | Energy | 2025 |
| Luminous IT Ltd | Information & communication | 2017 |
| Luna Nest Group Ltd | Real estate | 2025 |
| Luna Sleep Co Ltd | Wholesale & retail | 2026 |
| Lunaboot Studios Ltd | Information & communication | 2025 |
| Lunar Capital Ltd | Professional & scientific | 2023 |
| Lura Property Ltd | Real estate | 2020 |
| Luton Airport Hotel Limited | Extraterritorial | 2012 |
| LUX Photodigital Holdings Ltd | Financial services | 2015 |
| Luxe Accountants Ltd | Professional & scientific | 2023 |
| Luxe and Bloom Events Ltd | Administrative & support | 2018 |
| Luxelaneuk Ltd | Wholesale & retail | 2025 |
| Luxem Productions Ltd | Information & communication | 2025 |
| Luximom Limited | Administrative & support | 2009 |
| Luxury Asset Advisor Ltd | Wholesale & retail | 2023 |
| Luxury Granite Ltd | Construction | 2023 |
| Luxury Nails 10 Ltd | Other services | 2024 |
| LV Tattoo Collective Limited | Other services | 2026 |
| LVL Global Limited | Real estate | 2023 |
| LW PT Ltd | Arts & recreation | 2024 |
| Lyco Investments Limited | Financial services | 2025 |
| Lydia Bright Properties Limited | Real estate | 2013 |
| Lydia Rose Promotions Limited | Administrative & support | 2017 |
| Lydia Rose Properties Ltd | Real estate | 2018 |
| Lyga Properties Ltd | Real estate | 2021 |
| LYN Oakes Limited | Manufacturing | 1982 |
| Lynch (I.E.I.) Limited | Construction | 1995 |
| Lyndhurst Build Limited | Construction | 2025 |
| Lyne,Frank & Wagstaff,Limited | Real estate | 1919 |
| Lynford Close Management Company Limited | Real estate | 1996 |
| Lynsey DE Paul Music Limited | Information & communication | 1975 |
| Lynton Road Ltd | Real estate | 2013 |
| Lynwood (South Woodford) Management Co Ltd | Households | 2025 |
| Lyons Court Management Company Limited | Households | 1998 |
| Lyonsdown Church Partnership | Other services | 2005 |
| Lyonsdown Court Property Management Co.Limited | Households | 1962 |
| Lyted & Plum Enterprises Ltd | Other services | 2014 |
| M & J Bishop Property LLP | | 2022 |
| M & L London Ltd | Wholesale & retail | 2016 |
| M and a Property Lettings Ltd | Real estate | 2020 |
| M C Electrical Engineering Ltd | Construction | 2025 |
| M C W Homes Ltd | Real estate | 2019 |
| M Cerri Construction Ltd | Construction | 2024 |
| M Electrics Ltd | Construction | 2018 |
| M G Burke Management Services Limited | Real estate | 2014 |
| M G P Medicals Ltd | Health & social care | 2016 |
| M Health Recruitment Ltd | Health & social care | 2022 |
| M J Bickers Limited | Professional & scientific | 2018 |
| M J F W Consulting Limited | Administrative & support | 2011 |
| M K Breckland Promotions Limited | Real estate | 1986 |
| M Ozkor Ltd | Administrative & support | 2011 |
| M P Dudley Ltd | Construction | 2026 |
| M P Properties (London) Ltd | Real estate | 2023 |
| M R 33 London Limited | Administrative & support | 2025 |
| M Real Estate Ltd | Real estate | 2020 |
| M S Services & Logistics Limited | Wholesale & retail | 2025 |
| M Trade Links Limited | Wholesale & retail | 2021 |
| M&A Foster Ltd | Real estate | 2018 |
| M&B Hair and Beauty Limited | Other services | 2026 |
| M&D Financial Services Limited | Financial services | 2022 |
| M&E Contracting Limited | Administrative & support | 2013 |
| M&K Constructors Limited | Construction | 2022 |
| M&K Dental Limited | Health & social care | 2024 |
| M&M Aviation Consultancy Ltd | Transport & logistics | 2025 |
| M&M Crew Limited | Construction | 2012 |
| M&N Finance Ltd | Administrative & support | 2015 |
| M&T Professional Cleaning Services Ltd | Administrative & support | 2024 |
| M&W-Uk Ltd | Real estate | 2021 |
| M-Kou Commercial Ltd | Hospitality | 2018 |
| M-Xr Limited | Information & communication | 2018 |
| M. Aris Holdings Limited | Real estate | 1976 |
| M. K. Walsh Limited | Construction | 2011 |
| M. SAI Ltd | Professional & scientific | 2017 |
| M.D Professionals Ltd | Other services | 2024 |
| M.E.L. Services Limited | Professional & scientific | 2015 |
| M.G Collections UK Limited | Wholesale & retail | 2025 |
| M.K. Antiques & Restoration Ltd | Wholesale & retail | 2019 |
| M.Patricia Property Ltd | Real estate | 2022 |
| M.Prigmore Electrical Limited | Construction | 2011 |
| M.R Freight Limited | Transport & logistics | 2025 |
| M.V.T.A Limited | Arts & recreation | 2024 |
| M.Visuals Media Limited | Professional & scientific | 2022 |
| M1978 Limited | Construction | 2013 |
| M2 Property Services Limited | Construction | 2025 |
| M25 Scaffolding Limited | Construction | 1987 |
| M3L Solutions Ltd | Construction | 2009 |
| MA Empire Ltd | Real estate | 2019 |
| MA Legal Limited | Professional & scientific | 2015 |
| MA Motor Repairs Ltd | Wholesale & retail | 2023 |
| MA Property Collective Ltd | Real estate | 2024 |
| MA Strategix Ltd | Professional & scientific | 2011 |
| Maasai Mara Females of the Pride C.I.C. | Education | 2025 |
| Mabzi (UK) Limited | Other services | 2006 |
| MAC & Weld Limited | Construction | 2020 |
| MAC Best Trading UK Ltd | Wholesale & retail | 2020 |
| MAC Roofing (London) Limited | Construction | 2014 |
| Macgill of Kensington LLP | | 2009 |
| Macgregor & Macgregor Installations Limited | Professional & scientific | 2012 |
| Mackenzie Energy Consulting Limited | Professional & scientific | 2012 |