| LNG Specialists Ltd | Professional & scientific | 2016 |
| Lockguard Limited | Real estate | 1988 |
| Loftus Development Ltd | Construction | 2020 |
| Logical Consulting Limited | Information & communication | 2010 |
| Logicode UK Limited | Information & communication | 2021 |
| Logjoint Limited | Construction | 1989 |
| Lombards Family Holdings Ltd | Financial services | 2025 |
| London Nest Limited | Education | 2010 |
| Londonandsurrey Psychotherapy Ltd | Health & social care | 2021 |
| Londres Facile Limited | Real estate | 2012 |
| Long Island Resident's Association Ltd | Administrative & support | 2008 |
| Longcliff Ltd | Professional & scientific | 2007 |
| Longdene Developments Limited | Real estate | 1983 |
| Look UP Prints Ltd | Wholesale & retail | 2016 |
| Lorewa (UK) Limited | Administrative & support | 2015 |
| Loughrigg Fell Holding Ltd | Financial services | 2024 |
| Louise Hill-Patrick Ltd | Professional & scientific | 2017 |
| Lovegunn Ltd | Professional & scientific | 2017 |
| Lower Street (Haslemere) Limited | Households | 2002 |
| Lower Street Investments Ltd | Professional & scientific | 2007 |
| Lower Street Residential Limited | Extraterritorial | 2013 |
| LSG Surgery Ltd | Health & social care | 2022 |
| Lucias Luxury Clothing Limited | Wholesale & retail | 2021 |
| Lucid Media Consultancy Ltd | Professional & scientific | 2024 |
| Lucio.Libero Limited | Wholesale & retail | 2023 |
| Luffdon Properties Ltd | Real estate | 2026 |
| LUX Cleaning Haslemere Ltd | Administrative & support | 2025 |
| LUX Theatre Arts Ltd | Education | 2021 |
| Luxio Limited | Real estate | 2012 |
| Luxury Representation Services Ltd | Administrative & support | 2023 |
| LVX Limited | Other services | 2009 |
| Lynchmere Management Limited | Professional & scientific | 2019 |
| Lyndon-Skeggs Consulting Limited | Professional & scientific | 2022 |
| Lyria Advisory Ltd | Professional & scientific | 2026 |
| M & C Electrical & Panther Sales Ltd | Wholesale & retail | 2025 |
| M & C Electrical Limited | Wholesale & retail | 2016 |
| M a Starling Ltd | Information & communication | 2008 |
| M C Pathology Ltd. | Health & social care | 2022 |
| M J Fitzpatrick Family Law Ltd | Professional & scientific | 2021 |
| M.A. Rice & SON Limited | Agriculture & fishing | 1964 |
| MAC PM Limited | Construction | 2016 |
| Macaulay Assurance Consultants Limited | Financial services | 1970 |
| MAD Brand Group UK Ltd | Wholesale & retail | 2025 |
| MAD Brand Products Ltd | Professional & scientific | 2025 |
| MAD Group Holdings UK Ltd | Financial services | 2026 |
| Madame VY Ltd | Other services | 2022 |
| Maggie Walton-Swan Interior Design Ltd | Extraterritorial | 2012 |
| Maita Property Enterprise Limited | Real estate | 2018 |
| Malagasy Service Limited | Wholesale & retail | 2017 |
| Malamar Taste Limited | Hospitality | 2019 |
| MAM Aviation Limited | Transport & logistics | 1990 |
| Management Contract Services Limited | Agriculture & fishing | 2008 |
| Mandelyn Services Limited | Professional & scientific | 2016 |
| Manor LEA Residents Association Limited | Households | 1971 |
| Manse Pool Limited | Financial services | 2022 |
| Mansell IT Consultancy Limited | Information & communication | 2012 |
| Maple & Oak Consulting Limited | Information & communication | 2019 |
| Marcanna Consulting Limited | Information & communication | 2026 |
| Marchmaine Limited | Transport & logistics | 2019 |
| Marcus Terrace Property Limited | Households | 2014 |
| Marcus Wells Fencing Limited | Agriculture & fishing | 2014 |
| Marilyn and Martha Limited | Real estate | 2023 |
| Market Distribution Solutions Limited | Professional & scientific | 2004 |
| Marketingmentor.Net Ltd | Professional & scientific | 2001 |
| Marlin Ribs Limited | Arts & recreation | 2017 |
| Marshallart Limited | Information & communication | 2008 |
| Marshmere Holdings Ltd | Real estate | 2021 |
| Marston Forestry Ltd | Agriculture & fishing | 2018 |
| Masoslounge Limited | Wholesale & retail | 2024 |
| Matt Gander Associates Limited | Professional & scientific | 2015 |
| MAY & Grace Bridal Boutique Ltd | Wholesale & retail | 2017 |
| Mayfair Lane Consulting Limited | Professional & scientific | 2019 |
| Mayfield Rest Home Limited | Health & social care | 2011 |
| Maytree Investment Properties Ltd | Real estate | 2015 |
| Mazars Property Limited | Real estate | 2020 |
| MB Cyclery Ltd | Wholesale & retail | 2017 |
| Mcaplan Ltd | Construction | 2023 |
| MCG Group Limited | Professional & scientific | 1992 |
| MCR Polo Ltd | Arts & recreation | 2014 |
| MD Counselling Ltd | Other services | 2010 |
| Mdso Limited | Professional & scientific | 2013 |
| Meame Limited | Wholesale & retail | 2013 |
| Meaningful Interventions Limited | Professional & scientific | 2019 |
| Medical Artist Limited | Professional & scientific | 2016 |
| Meguro Investments Ltd | Real estate | 2017 |
| Meguro Property Ltd | Construction | 2017 |
| Melia Events Ltd | Hospitality | 2024 |
| Merrow Tyres Limited | Extraterritorial | 2004 |
| MFY LEE Services Limited | Administrative & support | 2018 |
| MGC Home Improvements Ltd | Construction | 2024 |
| MGP Services Limited | Professional & scientific | 2023 |
| Mhha Investment Limited | Real estate | 2017 |
| MHM Europe Ltd | Hospitality | 2015 |
| MHM Spa LES Bains Ltd | Hospitality | 2020 |
| Miah Commercial Assets Ltd | Other services | 2022 |
| Miah Family Holdings Ltd | Financial services | 2022 |
| Michael Courtney Family Butchers Limited | Wholesale & retail | 2013 |
| Michael Keeley Consulting Ltd | Professional & scientific | 2013 |
| Michelle Ashby Ltd | Administrative & support | 2019 |
| Michelle ORI Paris Limited | Wholesale & retail | 2022 |