| LOS Creative Agency Limited | Arts & recreation | 2022 |
| LOS Digital Ltd | Information & communication | 2025 |
| Love & Lester (Civil Engineering) Limited | Construction | 2010 |
| Love Beauty Limited | Other services | 2012 |
| Love IT Entertainments Limited | Administrative & support | 2016 |
| LOW Site Services Ltd | Administrative & support | 2025 |
| Lowe Steel Services Ltd | Manufacturing | 2026 |
| LRJ Property Developments Ltd | Extraterritorial | 2021 |
| LSM Roofing Limited | Construction | 2013 |
| LU Coaching Ltd | Education | 2024 |
| Lukasz Jamrozik Drylining Ltd | Construction | 2018 |
| Luma Engineering Ltd | Manufacturing | 2012 |
| Lumispell Ltd | Construction | 2025 |
| Lune Inc Ltd | Wholesale & retail | 2019 |
| Lustr Car Detailing Limited | Wholesale & retail | 2023 |
| LUX Power Services Ltd | Construction | 2023 |
| M & B M Motors Limited | Wholesale & retail | 2018 |
| M & T Edwards Limited | Construction | 2013 |
| M & T Healthcare Limited | Health & social care | 2004 |
| M and M Essex Developments Limited | Construction | 2017 |
| M Menzies Ltd | Construction | 2015 |
| M R Construction & Carpentry Ltd | Construction | 2021 |
| M Shipman Autos Limited | Wholesale & retail | 2015 |
| M&D Foods Ltd | Manufacturing | 2018 |
| M&M Vehicle Sales Ltd | Wholesale & retail | 2025 |
| M&T Properties Limited | Construction | 2023 |
| M&Y Brothers Ltd | Real estate | 2023 |
| M. a. D. Properties Limited | Real estate | 1998 |
| M.A. Richards Ltd | Professional & scientific | 2018 |
| M.A.D Flat Roofing Ltd | Construction | 2018 |
| MA Branding Ltd | Manufacturing | 2026 |
| MAC Aesthetics Limited | Health & social care | 2026 |
| Machinegunlukey Ltd | Information & communication | 2025 |
| Magic Property Management Ltd | Real estate | 2026 |
| Maguires ADI & PNM Limited | Hospitality | 2019 |
| Mainstream Logistics Limited | Transport & logistics | 2009 |
| Mainz Utilities Limited | Construction | 2024 |
| Makay Ltd | Wholesale & retail | 2023 |
| Manapa Housing Solutions Ltd | Real estate | 2025 |
| Mannpower Investments Limited | Professional & scientific | 2026 |
| Mannytech Solutions Limited | Information & communication | 2024 |
| Marabo's Kitchen Ltd | Hospitality | 2024 |
| MARCHELA83 Ltd | Transport & logistics | 2019 |
| Margins Limited | Real estate | 1997 |
| Marlenrich Ltd | Construction | 2019 |
| Marsom Driveways Ltd | Construction | 2015 |
| Martin Clover Limited | Construction | 2008 |
| Marts Blinds Limited | Other services | 2013 |
| Mascot Pets Ltd | Wholesale & retail | 2020 |
| Mason Samuel's Ltd | Construction | 2021 |
| Mastercool Air Conditioning Limited | Energy | 2011 |
| Masters Pool Solutions Limited | Administrative & support | 2022 |
| Mastertrust Build Limited | Construction | 2026 |
| Matia School of Motoring Ltd | Education | 2024 |
| Matt Lumby Design Ltd | Other services | 2014 |
| Max's Autoservice Ltd | Manufacturing | 2020 |
| Maxwell TM Ltd | Construction | 2025 |
| Mayfair Care Services Ltd | Health & social care | 2002 |
| Mayflower (1620) Limited | Information & communication | 2024 |
| Maynard Heady (Nominees) Limited | Extraterritorial | 1997 |
| Maynard Heady LLP | | 2008 |
| Mayshore Limited | Wholesale & retail | 2016 |
| Mc-Squared Mechanical Services Ltd | Construction | 2011 |
| Mccartney Accountants Limited | Professional & scientific | 2025 |
| MCD Commercials Ltd | Wholesale & retail | 2025 |
| MCG Cleaning Services Limited | Administrative & support | 2009 |
| Mcquilliam Holdings Ltd | Financial services | 2025 |
| Medivecta Ltd | Professional & scientific | 2026 |
| Medus Ltd | Transport & logistics | 2019 |
| MEG Facilities Ltd | Construction | 2024 |
| Melishem Academy CIC | Education | 2025 |
| Melishem Limited | Information & communication | 2023 |
| Meresca VLD Construction Ltd | Construction | 2025 |
| Meridian Colour Graphics Limited | Manufacturing | 1998 |
| Meskis Construction Ltd | Construction | 2026 |
| Metropolis Trading Limited | Hospitality | 2011 |
| Metwin Engineering Limited | Manufacturing | 2009 |
| Meyas Investments Limited | Extraterritorial | 2025 |
| MGM Stocktaking Limited | Administrative & support | 2023 |
| MGM Training Limited | Education | 2003 |
| MHE Solutions Ltd | Manufacturing | 2019 |
| Mhouse Ltd | Wholesale & retail | 2016 |
| Michael Fabs Ltd | Construction | 2019 |
| Michael Goodwin Golf Ltd | Wholesale & retail | 2022 |
| Michael Stevens Developments Limited | Construction | 2022 |
| Mick Layton Consultancy Services Ltd | Financial services | 2024 |
| Micro Electronics Dynamics Limited | Other services | 2017 |
| Middlemanmcfarlane Ltd | Wholesale & retail | 2026 |
| Middlemead Close Flats Limited | Households | 1997 |
| Midley U.K Ltd | Health & social care | 2016 |
| MIH Accounting Solutions Limited | Professional & scientific | 2011 |
| MIH Financial Solutions Limited | Professional & scientific | 2011 |
| Miles Bathrooms & Kitchens Limited | Construction | 2024 |
| Miljade Property Services Ltd | Real estate | 2025 |
| Mill END Works Ltd | Other services | 2026 |
| Mill Mount Investments Limited | Administrative & support | 2024 |
| Millsip Couriers Limited | Transport & logistics | 2023 |
| Millward Marketing Ltd | Wholesale & retail | 2018 |
| Mineral Logistics Limited | Extraterritorial | 2014 |
| Minifree Ltd | Wholesale & retail | 2014 |