| Long Hair in London Limited | Other services | 2011 |
| Long Stop Consulting Limited | Professional & scientific | 2024 |
| Longhorn Haulage Ltd | Transport & logistics | 2025 |
| Longmead Land Limited | Professional & scientific | 1994 |
| Longmoor Business Services Limited | Professional & scientific | 2006 |
| Lonsin Capital Management Limited | Financial services | 2011 |
| Lonsin Surveyors Limited | Real estate | 2024 |
| LS Motors Ltd | Manufacturing | 2013 |
| Lucksun Partners Limited | Real estate | 2021 |
| Lucy Hobbs Limited | Administrative & support | 2005 |
| Ludshott Consulting Ltd | Information & communication | 2025 |
| Lulukrumb Ltd | Manufacturing | 2026 |
| Luminous Industries Ltd | Information & communication | 2023 |
| Luxeloom LDN Limited | Wholesale & retail | 2024 |
| LV Phil Limited | Wholesale & retail | 2025 |
| LW Sport Limited | Arts & recreation | 2023 |
| M-Power Systems Limited | Information & communication | 2009 |
| MAD About Book-Keeping Limited | Professional & scientific | 2011 |
| Madeira Fish Bar Ltd | Hospitality | 2020 |
| Make Everyday Account Ltd | Professional & scientific | 2023 |
| Mana Innovation Group Limited | Wholesale & retail | 1979 |
| Managed Acres Ltd | Agriculture & fishing | 2011 |
| Mango Bookkeeping & Accounts Ltd | Professional & scientific | 2017 |
| Mango Partners Limited | Real estate | 2021 |
| Mario Foods Ltd | Hospitality | 2023 |
| Mark Rimmer Ltd | Professional & scientific | 2024 |
| Market Focus Research Limited | Information & communication | 1997 |
| Marnies Munchies Ltd | Hospitality | 2024 |
| Martin Payne Ltd | Construction | 2003 |
| Mastoro Solutions Ltd | Administrative & support | 2025 |
| Matans Care Limited | Health & social care | 2016 |
| Mauve Spring Ltd | Health & social care | 2020 |
| MB Builders and Decorators Ltd | Construction | 2011 |
| Mbrv Consultants Limited | Professional & scientific | 2010 |
| MCK Developments Limited | Construction | 2023 |
| Mckeand Limited | Professional & scientific | 2018 |
| MD Design (Southern) Ltd | Professional & scientific | 2020 |
| Media Broadcast Satellite UK Ltd | Information & communication | 2025 |
| Mega Structure Consulting Limited | Construction | 2013 |
| Mercer's Gym Community Project CIC | Arts & recreation | 2023 |
| Meridian Distribution and Marketing Limited | Manufacturing | 2003 |
| Messy Designs Limited | Manufacturing | 2011 |
| Metalweld-Solutions Ltd | Manufacturing | 2016 |
| Metamo Process Technology Ltd. | Professional & scientific | 2011 |
| MG Engagement Ltd. | Professional & scientific | 2009 |
| Milesound Ltd | Information & communication | 2021 |
| Mimpi Manis Ltd | Hospitality | 2025 |
| Minatec Research Limited | Professional & scientific | 1987 |
| Mindflex Ltd | Financial services | 2024 |
| Mindrush Limited | Wholesale & retail | 2007 |
| Mini Explorers Club Limited | Health & social care | 2023 |
| Minith Labs Ltd | Information & communication | 2025 |
| Mittles Ltd | Professional & scientific | 2006 |
| Mizo Momo Ltd | Hospitality | 2025 |
| MK Tavern Ltd | Hospitality | 2024 |
| Mkcb Holdings Limited | Real estate | 2022 |
| Mlimani Investments Ltd | Health & social care | 2024 |
| MMB Project Management Consultants Ltd | Professional & scientific | 2023 |
| Mobidaze Limited | Information & communication | 2012 |
| Modulaa Limited | Professional & scientific | 2022 |
| Molli Baby Clinic Limited | Professional & scientific | 2013 |
| Molli Baby Limited | Professional & scientific | 2013 |
| Molli Medical Limited | Professional & scientific | 2013 |
| Monkton Joinery Limited | Manufacturing | 2023 |
| Montrose Close (Heathervale) Residents Association Limited | Households | 1985 |
| MORE4X4 Holdings Limited | Professional & scientific | 2022 |
| MORE4X4 Services Limited | Wholesale & retail | 2021 |
| Moss Master Hampshire Ltd | Extraterritorial | 2016 |
| Moss Master Ltd | Administrative & support | 2015 |
| Moss Master Surrey Ltd | Administrative & support | 2016 |
| MPP Engineering Ltd | Manufacturing | 2019 |
| MR ZEN Limited | Information & communication | 2008 |
| MSL Global (Holdings) Limited | Professional & scientific | 2018 |
| MSL Global Limited | Administrative & support | 1980 |
| MTD Help Ltd | Information & communication | 2024 |
| MTS Garage Ltd | Wholesale & retail | 2025 |
| Muelle Norte Consultancy Ltd | Professional & scientific | 2021 |
| Mujeeb Services Ltd | Transport & logistics | 2025 |
| Multi Design & Engineering Limited | Professional & scientific | 1994 |
| Multigun Ltd | Arts & recreation | 2017 |
| Multimediaworlduk Ltd | Wholesale & retail | 2010 |
| Murata Power Solutions (Celab) Limited | Manufacturing | 1971 |
| MW Property Rentals Ltd | Real estate | 2023 |
| Mycena Energy Limited | Construction | 2021 |
| Mycena Systems Ltd | Manufacturing | 2019 |
| Mygoats Limited | Information & communication | 2021 |
| MZL Glazing Ltd | Construction | 2024 |
| MZN Ltd | Professional & scientific | 2020 |
| Mzuri Design Limited | Professional & scientific | 2013 |
| N S Crawley Builders & Decorators Ltd | Construction | 2011 |
| N.C.E. Consulting Limited | Professional & scientific | 2007 |
| Nagereg Inc Ltd | Professional & scientific | 2014 |
| Nakambe Wildlife Reserve Limited | Agriculture & fishing | 2025 |
| Namar 2009 Ltd | Health & social care | 2018 |
| Natty Peptides Ltd | Wholesale & retail | 2025 |
| Nebula Blockchain Consulting Limited | Information & communication | 2024 |
| Nelson 17 Limited | Arts & recreation | 2018 |
| Neurotechno Ltd | Information & communication | 2022 |
| Nevaeh Private Ltd | Hospitality | 2026 |
| New AGE Construction Limited | Construction | 2024 |