| Land Network (South Bedfordshire) Limited | Administrative & support | 2004 |
| Landelis Limited | Real estate | 1998 |
| Laus DEO Limited | Real estate | 2005 |
| Lazors Limited | Other services | 2000 |
| LDG Plastering Ltd | Construction | 2022 |
| Leannechadwickhair Limited | Other services | 2020 |
| Leaward Developments Limited | Construction | 1991 |
| Leisure Management Services Limited | Professional & scientific | 2007 |
| Lezash Ltd | Information & communication | 2019 |
| LF Infrastructure Limited | Construction | 2014 |
| Lillibet Court Limited | Health & social care | 1999 |
| Linoakley (NO. 107) Limited | Extraterritorial | 1921 |
| Linoakley (NO. 108) Limited | Extraterritorial | 1945 |
| Little Hollow Ltd | Real estate | 2014 |
| London and Northern Limited | Construction | 2007 |
| London Mayfair Limited | Administrative & support | 2015 |
| London Sailplanes Limited | Arts & recreation | 1938 |
| Luton Friendship Homecarers | Health & social care | 2000 |
| Luton Tamil Kalvikkoodam | Education | 2016 |
| Lynton Management Limited | Health & social care | 1999 |
| M & M Media Limited | Information & communication | 2001 |
| M D Plating Limited | Manufacturing | 1985 |
| M Greenwood Roofing Limited | Construction | 2002 |
| M J Hillson Limited | Construction | 1984 |
| M Oneil Brickwork Limited | Construction | 2002 |
| M S Foods Limited | Wholesale & retail | 1996 |
| M.K. Air Controls Limited | Wholesale & retail | 1974 |
| M.L.S. Electrics Limited | Construction | 2007 |
| Magnitude Property Holdings Limited | Construction | 2021 |
| Main Sequence Computer Consultancy Limited | Information & communication | 1992 |
| Malvern Software Limited | Information & communication | 1981 |
| Management & Communications Consultants Limited | Administrative & support | 1985 |
| Mand Properties LLP | | 2004 |
| Manor Construction (Herts) Limited | Construction | 1992 |
| Maplebrooke Holdings Limited | Financial services | 2025 |
| Maplebrooke Limited | Construction | 2003 |
| Mardley Stores Ltd | Wholesale & retail | 2003 |
| Mario Specchia Upholstery & Curtains Limited | Manufacturing | 2006 |
| Matrix Security Systems Limited | Administrative & support | 2004 |
| Mattermatics Ltd | Professional & scientific | 2024 |
| Maulden Vale Limited | Construction | 1989 |
| Mayfair Dairy Produce Limited | Wholesale & retail | 2007 |
| Meadway Driving School Limited | Education | 2006 |
| MED Media Collective UK Limited | Other services | 2026 |
| Media Management Corporation Limited | Information & communication | 1995 |
| Meedou 888 Limited | Hospitality | 2007 |
| Memlink Systems Limited | Information & communication | 1996 |
| Mennie Construction Services Limited | Wholesale & retail | 2005 |
| MGG Holdings Ltd | Wholesale & retail | 2014 |
| MGG Trading Ltd | Manufacturing | 2012 |
| MGM UK Limited | Administrative & support | 2005 |
| Michael a Jacobs Limited | Information & communication | 1999 |
| Microhold Limited | Extraterritorial | 1999 |
| Microplot Ltd | Information & communication | 1982 |
| MID Bedfordshire Citizens Advice Bureau | Health & social care | 2005 |
| Millimetre Perfect Installations Limited | Construction | 2005 |
| MJD Air Conditioning Services Limited | Energy | 2001 |
| MK Controls Limited | Professional & scientific | 1999 |
| MMK Plaster Limited | Construction | 2004 |
| Monster Films & TV Ltd | Information & communication | 2007 |
| Mook Consulting Limited | Information & communication | 2011 |
| Moor END Farming Limited | Extraterritorial | 2002 |
| Mordhill Limited | Professional & scientific | 2005 |
| Morespace Construction Ltd | Construction | 2020 |
| Morgans Construction Limited | Administrative & support | 2017 |
| Moroloy Merchant Ltd | Wholesale & retail | 2023 |
| Mortgages JUST4U Ltd | Financial services | 2007 |
| Motorbodies Luton Limited | Real estate | 2002 |
| Mpress UK Limited | Manufacturing | 2002 |
| MR Gates Fabrication Specialists Limited | Manufacturing | 2009 |
| Muhammad Group Limited | Extraterritorial | 2008 |
| MUK Consultants Limited | Professional & scientific | 2013 |
| Multiple Business Group Limited | Hospitality | 2022 |
| Murrayoung Limited | Professional & scientific | 1997 |
| Muse Events | | 2005 |
| Musictrack Limited | Wholesale & retail | 2004 |
| Musicworks (Chamber Courses) | Education | 2003 |
| Mutts and Moggs Limited | Wholesale & retail | 2025 |
| Mystery Football Jersey Ltd | Administrative & support | 2019 |
| N & D Local Discount Food & Wine Limited | Wholesale & retail | 2013 |
| N & R Services Limited | Mining & quarrying | 1996 |
| N R Daws Insurance Consultants Limited | Financial services | 2004 |
| N S M Projects Limited | Real estate | 2006 |
| N.A. Rigby & Associates Limited | Professional & scientific | 1999 |
| Nanco Estates Limited | Real estate | 2001 |
| Nash Limited | | 1983 |
| Navigator MSL Limited | Wholesale & retail | 1946 |
| Nayan Logistique & Chauffeur Services Ltd | Transport & logistics | 2023 |
| Nesta Health Services Limited | Health & social care | 2023 |
| New Century (U.K.) Limited | Administrative & support | 1989 |
| New Century Doors Limited | Manufacturing | 2001 |
| New Healthcare Limited | Health & social care | 2003 |
| Nextwave Limited | Administrative & support | 2004 |
| NJG Holdings Limited | Professional & scientific | 2002 |
| North END MGT Co Ltd | Households | 2022 |
| Noulin Developments Limited | Real estate | 1970 |
| Novaloca Limited | Professional & scientific | 2007 |
| Nude Creative Limited | Professional & scientific | 2001 |
| NVS Squared Ltd | Manufacturing | 2020 |
| O & K Properties Limited | Professional & scientific | 2005 |