| Maypole House School | Administrative & support | 2005 |
| MB International Limited | Administrative & support | 2006 |
| MBP Home Estates Limited | Real estate | 2000 |
| MCL Property Limited | Real estate | 2007 |
| MCL Property Managed Projects Ltd | Real estate | 2021 |
| MCL Property Special Projects Limited | Other services | 2010 |
| Mclean Decorators Limited | Construction | 2002 |
| Mcveigh Technical Solutions Limited | Manufacturing | 1999 |
| Mdds Limited | Real estate | 2002 |
| Mdigital Consulting Services Limited | Information & communication | 1997 |
| Medically Limited | Health & social care | 2001 |
| Medici Construction Limited | Construction | 1999 |
| Meesha Graphics (Leicester) Limited | Manufacturing | 2003 |
| Melliard Motorsport Limited | Manufacturing | 2024 |
| Melliard of London Ltd | Manufacturing | 2018 |
| Melton Cash & Carry Limited | Wholesale & retail | 2005 |
| Melton Castle Flooring Limited | Wholesale & retail | 2007 |
| Metalium Limited | Manufacturing | 1999 |
| Metalways Limited | Agriculture & fishing | 1977 |
| Metin Pizza Coalville Ltd | Hospitality | 2025 |
| Meyer 9 Limited | Extraterritorial | 1912 |
| Meyer International Finance and Property Limited | Extraterritorial | 1919 |
| Michael Smith Electrical Contractor Ltd | Construction | 2008 |
| Micro Technology Services Limited | Information & communication | 2007 |
| MID SAT Limited | Information & communication | 2007 |
| Midland Truck Mounts Ltd | Administrative & support | 2007 |
| Midn Properties Limited | Financial services | 2019 |
| Mike B'S Security Locksmith Limited | Wholesale & retail | 1998 |
| Milltower Developments Limited | Real estate | 2006 |
| Milner Project Services Ltd | Professional & scientific | 2003 |
| Minarik Limited | Other services | 1997 |
| Minster Finance Limited | Financial services | 1970 |
| Miro Double Glazing Limited | Construction | 2005 |
| Mitro Limited | Wholesale & retail | 2017 |
| MJE Electrical & Compliance Ltd | Construction | 2026 |
| Mmmc (2004) Limited | Professional & scientific | 2004 |
| Mocrown Properties Limited | Real estate | 2002 |
| Monaco Fashion House Limited | Professional & scientific | 2014 |
| Mondi Properties Ltd | Real estate | 2024 |
| Moneil Limited | Real estate | 2002 |
| Morphix SFS and Lining Ltd | Construction | 2026 |
| Morvanta Limited | Financial services | 2023 |
| Moss Solicitors LLP | | 2004 |
| Mountley Holdings Limited | Real estate | 1999 |
| Mowbray Foam Limited | Manufacturing | 2002 |
| Mowtec Limited | Manufacturing | 2006 |
| MRS King's Pork Pies Limited | Manufacturing | 2007 |
| MSM Limited | Real estate | 1987 |
| MTS Security Group Ltd | Administrative & support | 2026 |
| Mukta Property Investments Limited | Real estate | 2024 |
| Multicargo Ltd | Transport & logistics | 2021 |
| Munro Star Limited | Real estate | 2022 |
| Murreck Ltd | Construction | 2018 |
| My French Chalet Management Ltd | Professional & scientific | 2005 |
| Myriad Business Solutions Ltd | Professional & scientific | 2004 |
| Myrtle Enterprizes Limited | Other services | 2006 |
| N & J C Design Limited | Professional & scientific | 2007 |
| N B Building Ltd | Construction | 2003 |
| N K Retail Limited | Wholesale & retail | 2006 |
| N. LAD Limited | Wholesale & retail | 1998 |
| Naboth's Vineyard Limited | Agriculture & fishing | 2001 |
| Nadeems 7 Ltd | Wholesale & retail | 2018 |
| Narborough Eyecare Ltd | Health & social care | 2002 |
| Natures Dispensary Ltd | Wholesale & retail | 1999 |
| Ncpc Applications Limited | Information & communication | 2006 |
| NDB Developments Limited | Administrative & support | 2008 |
| Ne-York Fashions Ltd | Wholesale & retail | 2001 |
| Neetaraj Limited | Wholesale & retail | 2004 |
| Nesta Property Management Ltd | Real estate | 2021 |
| Network Bearings Limited | Wholesale & retail | 1998 |
| Nevill Holt Festival Limited | Arts & recreation | 2013 |
| Nevis Mckinley Consulting Ltd | Professional & scientific | 2016 |
| New Century (Hinckley) Limited | Hospitality | 2022 |
| New Folk Development Limited | Information & communication | 2020 |
| New London Fashions Limited | Wholesale & retail | 2003 |
| Newline Midlands Limited | Construction | 1953 |
| Nicholls Hinckley Limited | Real estate | 1956 |
| Nigel Smith Alloys Limited | Manufacturing | 2002 |
| Nigel Warner Limited | Administrative & support | 2007 |
| Nightingales Nursing Home Limited | Health & social care | 1999 |
| Nimags Limited | Wholesale & retail | 2019 |
| Nimbus Diamond Tool & Machine Co. Limited | Extraterritorial | 1979 |
| Ningin Limited | Other services | 2007 |
| NMF Contracts Limited | Construction | 2004 |
| North Wilshire Carpets Limited | Wholesale & retail | 1986 |
| Northern Lake Limited | Professional & scientific | 2014 |
| Northern Testhouse (Leicester) Ltd | Professional & scientific | 2003 |
| Norton Taxi Services Limited | Transport & logistics | 1984 |
| Nssc Operations Limited | Wholesale & retail | 2001 |
| Nuovonero Limited | Professional & scientific | 2006 |
| Nutrel Products Limited | Manufacturing | 1987 |
| NVR Traders Ltd | Wholesale & retail | 2022 |
| Nwmp Limited | Financial services | 2023 |
| Oakley Property Developments Limited | Construction | 2002 |
| Oakswell Limited | Wholesale & retail | 1999 |
| Oasis Discotheques (Leicester) Limited | Arts & recreation | 1976 |
| Officesmart International Limited | Professional & scientific | 1994 |
| Okarno Limited | Manufacturing | 2001 |
| Old India Spice Company Limited | Manufacturing | 2005 |
| Oliver Harding Limited | Wholesale & retail | 2002 |