| Kemet Radio Limited | Information & communication | 2006 |
| KEN Lawton Limited | Professional & scientific | 2003 |
| Ken's Auto Spares Limited | Wholesale & retail | 1983 |
| Kentor Consultancy Limited | Wholesale & retail | 2008 |
| Key Delivery Ltd | Real estate | 2025 |
| Kickin' FUN Sports Ltd | Education | 2025 |
| Kierson Ltd | Construction | 2008 |
| Kilnwick Sprayers Limited | Wholesale & retail | 1983 |
| Kingsway UK Ltd | Professional & scientific | 2004 |
| Kirkby Portland Cricket Club Limited | Arts & recreation | 2007 |
| Kirketon Limited | Wholesale & retail | 2020 |
| Kirklington Farms Limited | Agriculture & fishing | 1986 |
| Kitchen Solutions (Langley Mill) Limited | Construction | 2006 |
| L & H Investments Limited | Financial services | 2023 |
| L'Avventura Limited | Professional & scientific | 1998 |
| L.H. Woodhouse & Co Limited | Manufacturing | 1995 |
| Laird Estates Group Holdings Limited | Real estate | 2020 |
| Laird Estates Group Management Limited | Real estate | 2020 |
| Lamb EWI Ltd | Construction | 2026 |
| Latham Farms Limited | Agriculture & fishing | 1959 |
| Latty International Ltd | Wholesale & retail | 1991 |
| Launay's Restaurant Limited | Hospitality | 2007 |
| LBT Rentals Limited | Real estate | 2024 |
| LE Chien ET MOI Ltd | Wholesale & retail | 2007 |
| LEE Reclaim Limited | Water & waste | 1997 |
| Legacy World Class Furniture Limited | Manufacturing | 2006 |
| Lenton Avenue Park Management Co. Limited | Households | 2003 |
| LET IT Ltd. | Real estate | 2004 |
| LFW Holdings Limited | Arts & recreation | 2001 |
| Liberty Mining Consultants (UK) Limited | Extraterritorial | 2007 |
| Linney Design Limited | Professional & scientific | 2000 |
| Linney Direct Limited | Manufacturing | 1995 |
| Linney Group Limited | Manufacturing | 2000 |
| Linney Print Limited | Manufacturing | 1983 |
| Live Well Property SW Limited | Real estate | 2024 |
| LJ Building Developments Limited | Construction | 2024 |
| Lloyd Wright Limited | Real estate | 2002 |
| Logobrand Field Marketing Ltd | Administrative & support | 2006 |
| Long Eaton Motor Company Limited | Wholesale & retail | 2003 |
| Longleat Property Limited | Real estate | 2002 |
| Lubeck Limited | Mining & quarrying | 1997 |
| Lumiera Properties Limited | Real estate | 2025 |
| Lynx Medical Holdings Limited | Financial services | 2026 |
| M B S Interiors Limited | Manufacturing | 2003 |
| M J & M a Lakey Limited | Construction | 2005 |
| M. Burgess (Forestry) Limited | | 1957 |
| M.A.R.S.[2006] Limited | Construction | 2006 |
| M.S.W (UK) Limited | Construction | 1989 |
| MAC22 Limited | Information & communication | 2008 |
| Machine Mart Limited | Wholesale & retail | 1981 |
| Majordream Limited | | 1984 |
| Manns Pharmacy Limited | Wholesale & retail | 1999 |
| Manor Properties (East Midlands) Limited | Real estate | 1995 |
| Manor Stables Limited | Real estate | 2006 |
| Mansfield Anodisers Limited | Manufacturing | 1999 |
| Mansfield B I D Company Limited | Administrative & support | 2009 |
| Mansfield Rugby Union Football Club Limited | Arts & recreation | 1977 |
| Mansfield Tyres Limited | Wholesale & retail | 1996 |
| Marginblock Residents Management Limited | Administrative & support | 1992 |
| Mark Fowler Construction Ltd | Construction | 2007 |
| Mark Gray Associates Limited | Health & social care | 2007 |
| Marmalade Box Limited | Professional & scientific | 2005 |
| Marsh Civil Engineering Limited | Wholesale & retail | 2005 |
| Marwill Newark Limited | Administrative & support | 2005 |
| Mascari Design Solutions Ltd | Administrative & support | 2007 |
| Masding Capital Limited | Professional & scientific | 2023 |
| Masons Place Limited | Real estate | 1994 |
| Material Technologies Limited | Construction | 2000 |
| Maurice Hill Transport Limited | Transport & logistics | 1979 |
| Mayfair Properties (Northern) Limited | Professional & scientific | 1985 |
| Mayfair Properties (Nottingham) Limited | Real estate | 1986 |
| Maylite Industries Limited | Professional & scientific | 1998 |
| MC Services Investments Limited | Construction | 2000 |
| Mcloughlin Group PLC | Wholesale & retail | 1991 |
| MDB Service Consulting Limited | Information & communication | 2006 |
| Meldocs Limited | Health & social care | 2002 |
| Mellors & Kirk Limited | Wholesale & retail | 1988 |
| Mercserve Limited | Wholesale & retail | 2002 |
| Merriman Transport Limited | Transport & logistics | 2009 |
| Merzant Studios Limited | Information & communication | 2025 |
| Metal Process Services Limited | Manufacturing | 1996 |
| Metlane Limited | Real estate | 1994 |
| Metroberry Limited | Information & communication | 2019 |
| Micomms Limited | Professional & scientific | 2007 |
| Micro-Audit Limited | Manufacturing | 1980 |
| Midland Roots Ltd | Health & social care | 2025 |
| Midlands Flue Group Limited | Construction | 2023 |
| Midlands Response Limited | Administrative & support | 2006 |
| Mierce Miniatures Limited | Manufacturing | 2009 |
| Mike Maloney Country Butchers & Bakers Limited | Manufacturing | 2002 |
| MILANO1905 Ltd | Hospitality | 2025 |
| Mill Farm by LBB Limited | Extraterritorial | 2024 |
| Millcourt Shopfittings Limited | Wholesale & retail | 1995 |
| Millennium Travel (Mansfield) Limited | Transport & logistics | 2018 |
| Millunit Limited | Professional & scientific | 1990 |
| Minster Financial Solutions Limited | Financial services | 2005 |
| Mish Tech Ltd | Wholesale & retail | 2025 |
| MJ VIE Limited | Transport & logistics | 2007 |
| Molew Limited | Extraterritorial | 2005 |
| Montaged Limited | Information & communication | 2024 |