| Lost Leisure Limited | Arts & recreation | 2005 |
| Louis Lefevre Limited | Real estate | 1969 |
| Loverock Motor Parts Limited | Wholesale & retail | 1983 |
| Lowes Transport (Birmingham) Limited | Transport & logistics | 2002 |
| Lowes Transport (Scotland) Limited | Transport & logistics | 1975 |
| Lowes Transport Group Limited | Professional & scientific | 1964 |
| LSI Recruitment Ltd | Administrative & support | 2021 |
| LT Lets Limited | Real estate | 2001 |
| Ludgate (Moseley) Management Limited | Households | 1982 |
| Lumeter Limited | Manufacturing | 1978 |
| Luxury Executive Travel (UK) Ltd | Administrative & support | 2014 |
| Lyne Hill Escapes Ltd | Real estate | 2025 |
| M & D Power Limited | Other services | 2005 |
| M & H Fireplaces Limited | Administrative & support | 2003 |
| M & M Construction (Coventry) Limited | Construction | 2005 |
| M & T Homes Limited | Construction | 2002 |
| M a Gavin Limited | Construction | 2003 |
| M G Security Systems (UK) Ltd | Administrative & support | 2005 |
| M Gilbert Plumbing and Heating Services Limited | Construction | 2007 |
| M Hudson (Machine Removals) Limited | Manufacturing | 2002 |
| M J Talocrete Holdings Limited | Administrative & support | 2000 |
| M J Thom Carpenters Limited | Other services | 2005 |
| M P H Precision Machining Limited | Manufacturing | 2017 |
| M S D (WM) Limited | Wholesale & retail | 2007 |
| M W V Services Limited | Transport & logistics | 2004 |
| M. & J. Mahoney and Sons Ltd | Construction | 1970 |
| M. & W. Contractors (Pensnett) Limited | Manufacturing | 1974 |
| M. Barnwell Services Limited | Wholesale & retail | 1975 |
| M.A.H. Electrical Services Ltd | Construction | 2003 |
| M.B. Distribution Limited | Transport & logistics | 2000 |
| M.B.Carpenters & Joinery Limited | Construction | 2006 |
| M.F.Z. Investments Ltd | Real estate | 2004 |
| M.H.I.T. Limited | Information & communication | 2000 |
| M.I Solutions Ltd | Information & communication | 2000 |
| M.J. Interiors Limited | Construction | 2004 |
| M.J.K. (Kidderminster) Limited | Manufacturing | 2003 |
| M.M.A. Ltd | Health & social care | 2007 |
| M.R.G. (U.K.) Limited | Wholesale & retail | 1987 |
| M.S. Entertainments Limited | Arts & recreation | 1983 |
| M.S.B. News Ltd | Wholesale & retail | 2007 |
| M.T.B. Metafin Limited | Professional & scientific | 1976 |
| MA Performance Ltd | Arts & recreation | 2022 |
| Macbeth 24 Limited | Manufacturing | 1960 |
| Macphersons Appliances Direct Limited | Wholesale & retail | 1988 |
| Madaket Limited | Real estate | 1999 |
| Maelstrom Event Solutions Limited | Administrative & support | 2005 |
| MAG Air (Wolverhampton) Limited | Wholesale & retail | 2006 |
| Magdeburger Waescherei Limited | Administrative & support | 2004 |
| Magena Services Limited | Information & communication | 2005 |
| Magic Square Systems Limited | Information & communication | 1998 |
| Magyar Properties Limited | Real estate | 2019 |
| Maiden Properties Limited | Real estate | 1989 |
| Main Maintenance Ltd. | Construction | 1995 |
| Mainline Capital Limited | Professional & scientific | 1984 |
| Mainline Surfacing Ltd | Construction | 2024 |
| Maintenance Components Limited | Administrative & support | 1997 |
| Majorfax Castings Limited | Wholesale & retail | 1986 |
| MAK Front Ltd | Wholesale & retail | 2022 |
| MAK Tecno Ltd | Information & communication | 2015 |
| Malik Enterprises Limited | Real estate | 1998 |
| Malthouse Industrial Holdings Limited | Financial services | 2006 |
| Manchester Galvanizing Ltd | Manufacturing | 1954 |
| Mann & Grewal Properties Limited | Hospitality | 2005 |
| Mann Jitt Limited | Manufacturing | 2004 |
| Manorcrow Limited | Extraterritorial | 1967 |
| Mantech (U.K.) Limited | Wholesale & retail | 2001 |
| Manufacturing Dynamics Limited | Professional & scientific | 2007 |
| Mark One Automotive Limited | Manufacturing | 1996 |
| Mark Paul Polishing Limited | Manufacturing | 2000 |
| Marklew Holdings Ltd | Financial services | 1966 |
| Marshallsay Design Limited | Professional & scientific | 2007 |
| Martialartshop Limited | Wholesale & retail | 2003 |
| Martin Dempster Limited | Professional & scientific | 2006 |
| Martin Luther Limited | Extraterritorial | 2023 |
| Martineau Johnson Properties Limited | Real estate | 2002 |
| Martineau Secretaries Limited | Professional & scientific | 2001 |
| Mary Stevens Hospice Lottery Limited | Arts & recreation | 1999 |
| Masiv Promotions Limited | Manufacturing | 2009 |
| Master-Vent Limited | Construction | 1976 |
| Mastered Media Limited | Financial services | 2025 |
| Masters Pharmacy Limited | Wholesale & retail | 2002 |
| Matrix Tech Consultancy Limited | Wholesale & retail | 2026 |
| Matrix World Limited | Information & communication | 2003 |
| Matuk Business Services Limited | Professional & scientific | 2002 |
| Maxam Tire Solutions Limited | Manufacturing | 2015 |
| MAY Angel Ltd | Extraterritorial | 2025 |
| Mayerty Catering Limited | Wholesale & retail | 2023 |
| Mazen Matar Medical Services Ltd | Health & social care | 2022 |
| Mbfa Limited | Health & social care | 2023 |
| MBK (West Midlands) Limited | Health & social care | 2006 |
| Mcauliffe Environmental Limited | Construction | 2007 |
| Mccs International Limited | Transport & logistics | 2002 |
| MCD (Nottingham) Limited | Professional & scientific | 1911 |
| Mcdonald Automation Ltd | Professional & scientific | 2002 |
| MD Fletcher Limited | Other services | 2003 |
| Mdfd Limited | Real estate | 2003 |
| Me.So.Tec Limited | Professional & scientific | 2005 |
| Meadowbond Limited | Manufacturing | 1939 |
| Meanley Properties Limited | Real estate | 2003 |
| Meaujo Incorporations Limited | Professional & scientific | 1990 |