| Locumreach Limited | Administrative & support | 2016 |
| Lofts Transformation UK Ltd | Construction | 2021 |
| London and Surrey Mobile Mechanics Ltd | Wholesale & retail | 2026 |
| London Fine Limited | Wholesale & retail | 2013 |
| London Funeral Company Ltd | Other services | 2017 |
| London Plumbers 24/7 Limited | Construction | 2012 |
| London Private Hire Service Limited | Administrative & support | 2022 |
| London School of Diving Limited | Arts & recreation | 2002 |
| London Tutorial College Ltd | Education | 2015 |
| London Tutorial College Online Ltd | Education | 2015 |
| London Window Specialists Ltd | Construction | 2025 |
| London's Mobile Tyre Fitting Limited | Wholesale & retail | 2021 |
| Longcross Accounting Services Ltd | Information & communication | 2019 |
| Longcross Church Management Company Limited | Households | 2024 |
| Longs Holdings Limited | Financial services | 2008 |
| Lord Puppington Ltd | Real estate | 2008 |
| Lotte Investments Limited | Other services | 2022 |
| Loula Entertainment Ltd | Health & social care | 2026 |
| Loupes Direct Ltd | Manufacturing | 2016 |
| Love IS Everything Ltd | Other services | 2016 |
| Lucas Express Couriers Ltd | Transport & logistics | 2026 |
| Lucas's Mechanics Ltd | Wholesale & retail | 2020 |
| Luckyegg Solutions Limited | Information & communication | 2026 |
| Ludwell House Ltd | Households | 2021 |
| Luke Harrison Draper-Cave Ltd | Other services | 2025 |
| Luna Digital Ltd | Professional & scientific | 2019 |
| Lunevia London Limited | Manufacturing | 2026 |
| Luton's Saloon Limited | Other services | 2024 |
| LUX Nails Spa Ltd | Other services | 2024 |
| Luxe Estates (South East) Limited | Construction | 2019 |
| Luxeshiri Ltd | Wholesale & retail | 2024 |
| Lvgold Ltd | Other services | 2015 |
| Lyne Hill House Limited | Real estate | 2015 |
| Lyntima Ltd | Health & social care | 2022 |
| Lysandra Wildlife Consulting Limited | Professional & scientific | 2022 |
| Lyzz Creations Ltd | Wholesale & retail | 2017 |
| M and Z Autos Ltd | Wholesale & retail | 2024 |
| M Erratt Services Limited | Information & communication | 2017 |
| M Farrow Consulting Limited | Professional & scientific | 2019 |
| M Mcdonough Engineering Ltd | Professional & scientific | 2024 |
| M&R Driveways and Landscaping Ltd | Construction | 2025 |
| M.A Holdings Surrey Ltd | Energy | 2019 |
| M.D Whelan Carpentry & Joinery Ltd | Construction | 2016 |
| M.Francis Services Ltd | Administrative & support | 2011 |
| M.L 11 Consultants Ltd | Professional & scientific | 2024 |
| Maanya Recruitment Ltd | Information & communication | 2022 |
| Maanya Vitacare Limited | Manufacturing | 2023 |
| Macey Controls Limited | Manufacturing | 1992 |
| Machi Limited | Professional & scientific | 2013 |
| Machine Tool Servicing Ltd | Manufacturing | 2007 |
| Mackenzie Taylor Design Ltd | Information & communication | 2011 |
| Mageia Ltd | Professional & scientific | 2019 |
| Magic Automotive Ltd | Wholesale & retail | 2026 |
| Magic State Media Limited | Information & communication | 2023 |
| Magna Inc Ltd | Construction | 2019 |
| Magnificent Film and Television Ltd | Information & communication | 2019 |
| Magnificent Property Developers Ltd | Real estate | 2022 |
| Magnour Limited | Real estate | 2022 |
| Maia Energy Ltd | Financial services | 2007 |
| Maintenance Garden Services Ltd | Households | 2019 |
| Maison Inventory & Property Services Ltd | Administrative & support | 2020 |
| Maison Pelisse Ltd | Professional & scientific | 2025 |
| Makhand Ltd | Other services | 2017 |
| Mallare (UK) Limited | Transport & logistics | 2008 |
| Management Company of Bridge Court Limited | Other services | 1991 |
| Manester Design and Marketing Limited | Information & communication | 2002 |
| Manet Ltd | Information & communication | 2015 |
| Mansa IT Solutions Ltd | Information & communication | 2016 |
| Mansa Property Solutions Ltd | Real estate | 2020 |
| Mansa Tech Ltd | Information & communication | 2010 |
| Maplin Car Group Ltd | Wholesale & retail | 2023 |
| Marathon Bags Limited | Wholesale & retail | 2020 |
| Marco Industries Limited | Extraterritorial | 1992 |
| Maresca Property and Developments Limited | Construction | 2026 |
| Marius Calin Ltd | Construction | 2014 |
| Mark SIM Ltd | Arts & recreation | 2020 |
| Markus & Doros Ltd | Wholesale & retail | 2015 |
| Marooga Ltd | Professional & scientific | 2012 |
| Marss Partners Limited | Administrative & support | 2024 |
| Mastero Technologies Limited | Information & communication | 2023 |
| Masvito Ltd | Administrative & support | 2026 |
| Match Personnel Ltd | Administrative & support | 2022 |
| Matrix Accountancy Limited | Professional & scientific | 2017 |
| Matrix Security and Electrical Systems Ltd | Administrative & support | 2002 |
| Maturitz Limited | Professional & scientific | 2006 |
| Maurice Mandry Limited | Agriculture & fishing | 1947 |
| Maurizio Bertolone Ltd | Extraterritorial | 2025 |
| Maze Solutions Group Ltd | Administrative & support | 2023 |
| MB Football Coaching Ltd | Arts & recreation | 2025 |
| MC Films Limited | Arts & recreation | 2008 |
| MCL Creative Limited | Professional & scientific | 2024 |
| MD Shipbroking Limited | Professional & scientific | 2017 |
| Me&C Creative Limited | Professional & scientific | 2017 |
| ME4YOU Limited | Professional & scientific | 2025 |
| MEA TEC Distribution Ltd | Information & communication | 2025 |
| Meaningful Mornings Ltd | Wholesale & retail | 2021 |
| Mechanic Wizard Ltd | Wholesale & retail | 2019 |
| Medical Affairs Consultancy Limited | Professional & scientific | 2014 |
| Medical Despatch Event Services Limited | Transport & logistics | 2012 |
| Mediterranean Dream Ltd | Real estate | 2008 |