| LMJ Roofing and Building Ltd | Construction | 2023 |
| Lomatt Limited | Real estate | 2021 |
| Longstaff Power Solutions Ltd | Construction | 2025 |
| Lootify Hub Ltd | Wholesale & retail | 2026 |
| Lordirite Wines Limited | Wholesale & retail | 2025 |
| Lotus Childcare Limited | Health & social care | 2024 |
| Loukay Ltd | Hospitality | 2019 |
| LR Property Management Ltd | Real estate | 2015 |
| LRL Property (NE) Ltd | Real estate | 2021 |
| LSC Plant Limited | Manufacturing | 2021 |
| Lucky GY Ltd | Hospitality | 2026 |
| Luckystar Homes Ltd | Real estate | 2026 |
| Luminar Holdings Limited | Financial services | 2022 |
| Lumo.Tax Limited | Professional & scientific | 2014 |
| Luna Flux.Marketing Limited | Professional & scientific | 2024 |
| Lush Weddings & Events Ltd | Professional & scientific | 2025 |
| LUX Homie Limited | Real estate | 2023 |
| LUX Photo Booths Ltd | Professional & scientific | 2024 |
| LUX Wedding Photography Ltd | Professional & scientific | 2022 |
| M & M Services Heatworks LLP | | 2022 |
| M a Utilities Ltd | Construction | 2011 |
| M Robinson Roofing Limited | Construction | 2026 |
| M S Haque Ltd | Hospitality | 2025 |
| M&L Assets Limited | Real estate | 2020 |
| M7 Healthcare & Wellbeing Ltd | Financial services | 2012 |
| Machine Memberships Ltd | Arts & recreation | 2025 |
| Machine MMA Ltd | Arts & recreation | 2010 |
| Machine Property Investments Ltd | Real estate | 2025 |
| Made of Crumbs Ltd | Hospitality | 2021 |
| Made With Love Printing & Embroidery Ltd | Manufacturing | 2021 |
| Magnificentland Company Limited | Real estate | 2024 |
| Magnum Opus (NE) Ltd | Professional & scientific | 2018 |
| Maison DU SKS Ltd | Real estate | 2025 |
| Major Influence Ltd | Arts & recreation | 2014 |
| Major Influence Records Limited | Information & communication | 2019 |
| Makemake Planet Ltd | Real estate | 2020 |
| Mandalay Properties Limited | Real estate | 2018 |
| Mantrust (UK) Limited | Extraterritorial | 2007 |
| Mapleleaf Shopfitters Limited | Construction | 2009 |
| Marmax Products Limited | Manufacturing | 1982 |
| Marshall Services and Solutions Limited | Professional & scientific | 2020 |
| Marshall-Ddp Ltd | Professional & scientific | 2019 |
| Marshrow Construction Ltd | Construction | 2024 |
| Martel Instruments EBT Limited | Extraterritorial | 2008 |
| Martel Instruments Holdings Limited | Professional & scientific | 2006 |
| Martel Instruments Limited | Manufacturing | 1982 |
| Martin Amos Marine Ltd | Professional & scientific | 2022 |
| Martin Hall Properties Limited | Real estate | 2025 |
| Martin Kelly Services Limited | Construction | 2021 |
| Maryems Turkish Barbers Ltd | Other services | 2020 |
| Mathman Academy Ltd | Education | 2021 |
| Matmar Aesthetics Ltd | Other services | 2024 |
| Matson Hire Ltd | Transport & logistics | 2016 |
| Matthew Lorenzo Productions (Hurst) Ltd | Information & communication | 2022 |
| Matthew Lorenzo Productions Limited | Information & communication | 2021 |
| MAX P Motors Ltd | Wholesale & retail | 2023 |
| Maxcel Limited | Hospitality | 2023 |
| Maxxq Limited | Wholesale & retail | 2021 |
| Mccarthy & Sons Plumbing, Heating and Electrical Ltd | Construction | 2021 |
| Mckay Executive PA & Admin Services Ltd | Administrative & support | 2020 |
| MCM Advice Ltd | Financial services | 2018 |
| Mcvickers Free Solar Limited | Administrative & support | 2016 |
| Mcvickers Holdings Limited | Real estate | 2010 |
| Mcvickers Limited | Construction | 1975 |
| Mcvickers Solar Electric LLP | | 2011 |
| MD Access Ltd | Construction | 2026 |
| Memorabilia Museum Limited | Wholesale & retail | 2019 |
| Messrs. J. & J. Mitchell (Taymount) | | 1995 |
| MEZ9 Ltd | Administrative & support | 2022 |
| MGT Electrotech Ltd | Construction | 2018 |
| Miboto Limited | Real estate | 2021 |
| Michael Boyle Services Ltd | Construction | 2026 |
| Michael Curry Enterprises Ltd | Arts & recreation | 2016 |
| Michris Engraving Limited | Administrative & support | 2007 |
| Midori Matcha Limited | Wholesale & retail | 2024 |
| Milbank Architects Ltd | Professional & scientific | 2008 |
| Milbank Developments Ltd | Real estate | 2011 |
| Milbourne & Sons Limited | Real estate | 2022 |
| Milestone Inventories Ltd | Administrative & support | 2019 |
| Mill Lane Farming Limited | Agriculture & fishing | 2021 |
| Mille Trading Ltd | Administrative & support | 2025 |
| Miller Inc Limited | Construction | 2015 |
| Mitchell & Beeley Commercial Limited | Real estate | 2025 |
| Mitchell & Beeley Investments Ltd | Real estate | 2023 |
| Mitchell Beeley & Wallace Ltd | Households | 2022 |
| MJM Emporium Limited | Wholesale & retail | 2013 |
| MJW Financial Planning Ltd | Professional & scientific | 2018 |
| MKD (NE) Limited | Wholesale & retail | 2012 |
| Mmby Company Limited | Real estate | 2023 |
| MNC Property Group Limited | Construction | 2025 |
| Modvan Limited | Wholesale & retail | 2023 |
| Mojo GAS Services Ltd | Construction | 2017 |
| Monkridge Court Management Ltd | Households | 2024 |
| Monstein Residential Ltd | Real estate | 2016 |
| Montgomery Rose Ltd | Real estate | 2025 |
| Montys (NE) Leisure Ltd | Hospitality | 2025 |
| Moonfields Accounting Ltd | Professional & scientific | 2026 |
| Moonfire Beauty Ltd | Other services | 2024 |
| Moonstone Houses Limited | Real estate | 2022 |
| Moor Kitchen Limited | Hospitality | 2026 |