| Lindesays Arkwright Limited | Extraterritorial | 1998 |
| Lindesays Financial Services Limited | Extraterritorial | 1994 |
| Lindesays Independent Estate Agents Limited | Extraterritorial | 1994 |
| Lindesays Property Management Limited | Extraterritorial | 1999 |
| Link Rider Coaches Limited | Transport & logistics | 2003 |
| Links Garage (Parkstone) Limited | Wholesale & retail | 1963 |
| Linkstake Residents Management Limited | Real estate | 1987 |
| Linwood Software Limited | Information & communication | 2005 |
| Lions Gate Developments (Southern) Limited | Real estate | 2006 |
| Liritek Limited | Information & communication | 2004 |
| Lissenden-Burton Limited | Households | 1984 |
| Little Britten Ltd | Real estate | 2000 |
| Little Canford Holdings Ltd | Real estate | 1978 |
| Little Court Canford Cliffs Limited | Households | 2001 |
| Little India (UK) Limited | Hospitality | 2004 |
| Little Stars Education Ltd | Education | 2006 |
| Littleton Farm Limited | Agriculture & fishing | 1964 |
| Liverpool Victoria Banking Services Limited | Extraterritorial | 1947 |
| Liverpool Victoria Financial Advice Services Limited | Financial services | 1995 |
| Livingdesign Developments Limited | Construction | 2006 |
| LJ Education Limited | Education | 2019 |
| LJT Developments Limited | Construction | 2000 |
| Logobugs Plus Limited | Manufacturing | 1982 |
| Lomond Electronics Limited | Information & communication | 1998 |
| London Soundproofing Limited | Construction | 2015 |
| Lonland Heating Limited | Real estate | 1973 |
| Lord Haldon Limited | Hospitality | 2005 |
| Lost for Words Limited | Professional & scientific | 2006 |
| Lostwithiel Property Company Limited | Hospitality | 1963 |
| Lotus Global Group Ltd | Wholesale & retail | 2026 |
| Lower Whitechurch Farm Limited | Real estate | 1998 |
| LSF12 Donnelly UK Bidco, Limited | Financial services | 2023 |
| Lush Cosmetics Limited | Professional & scientific | 2001 |
| Lush Ltd. | Manufacturing | 1994 |
| Lush Manufacturing Limited | Manufacturing | 1997 |
| Lutton Farms (Steeple) Limited | Agriculture & fishing | 1961 |
| LV Equity Release Limited | Financial services | 1985 |
| LV Life Services Limited | Administrative & support | 2001 |
| LV Protection Limited | Financial services | 1984 |
| M & M Balfour Ltd | Real estate | 2002 |
| M C Builders (Dorset) Limited | Construction | 2002 |
| M C Norris Limited | Construction | 2006 |
| M F G Properties Limited | Real estate | 1999 |
| M J Snowden Limited | Construction | 2003 |
| M Robinson Limited | Construction | 2001 |
| M. J. Gale Limited | Construction | 2003 |
| M. Ploy Limited | Administrative & support | 1999 |
| M.A.M.P. Group Limited | Extraterritorial | 2008 |
| MA Capital International Firm Ltd | Administrative & support | 2025 |
| MAC Building Contractors Limited | Construction | 2001 |
| Magna Motor Company (Wessex) Ltd | Wholesale & retail | 2002 |
| Mahnoor HFX Ltd | Wholesale & retail | 2025 |
| Mampitts Farm Ltd | Other services | 2006 |
| Mani Contractors Ltd | Hospitality | 2017 |
| Manitou UK Limited | Manufacturing | 1972 |
| Manor Court (Ferndown) Management Limited | Real estate | 2004 |
| Manor Electronics Ltd | Manufacturing | 2004 |
| Mapeldown Limited | Real estate | 1978 |
| Maple Convenience Limited | Wholesale & retail | 2007 |
| Marchwood Technologies Limited | Manufacturing | 1992 |
| Mark Cunniffe Ltd | Arts & recreation | 2002 |
| Market Place (Blandford) Management Company Limited | Households | 1992 |
| Marketpoll Limited | Extraterritorial | 1981 |
| Marlboro Restaurant Limited | Hospitality | 2002 |
| Marsham Court Hotel Ltd | Hospitality | 1996 |
| Marshwood Vale Limited | Information & communication | 2001 |
| Martello Park Management (Poole) Limited | Households | 1975 |
| Martin and Company (Bridport) Limited | Professional & scientific | 2005 |
| MAT Foundry Group Limited | Professional & scientific | 2000 |
| Materfortis Developments Ltd | Construction | 2024 |
| Matt-Black Systems Limited | Professional & scientific | 2002 |
| Mattwalk Limited | Professional & scientific | 2003 |
| Matvale Holdings Ltd | Extraterritorial | 2006 |
| MAW Consultancy Limited | Professional & scientific | 2010 |
| Maxman Limited | Real estate | 1983 |
| MC Service Consultancy Limited | Information & communication | 2010 |
| MC2 Data Innovation Limited | Information & communication | 1999 |
| Mckenzie Guppy Ltd. | Manufacturing | 1994 |
| Mcmurtry Technology Limited | Extraterritorial | 2026 |
| Mcpm Limited | Construction | 2002 |
| Mcquillan Brothers (Builders) Limited | Construction | 1985 |
| MD Services (South) Limited | Wholesale & retail | 2003 |
| Mechanical Services (Wessex) LLP | | 2002 |
| Medics Away Limited | Wholesale & retail | 2002 |
| Megaflow Ltd | Wholesale & retail | 1996 |
| Mello Mello Ltd | Hospitality | 1997 |
| Mepax UK Limited | Administrative & support | 2007 |
| Merck UK | | 1996 |
| Meridian Cooling Ltd | Construction | 2005 |
| Merrivale Electrical Ltd | Construction | 2003 |
| Merville W Gover Limited | Wholesale & retail | 2003 |
| Mervyn Rose Engineering Limited | Construction | 2000 |
| Mess Ltd | Construction | 1986 |
| Message Direct Limited | Extraterritorial | 1994 |
| Metro Supermarket Dorchester Ltd | Wholesale & retail | 2024 |
| Metropolitan Land and House Company Limited(The) | Construction | 1878 |
| MFT Property Services Limited | Real estate | 2006 |
| MH Engineering Services Ltd | Manufacturing | 1997 |
| Michael Burton Developments (New Forest) Limited | Construction | 2003 |
| Michael Burton Properties Limited | Construction | 2003 |