| Lovett Tattoo & Piercing Ltd | Other services | 2023 |
| Loyalty Car Wash Ltd | Other services | 2014 |
| LP Motor Garage Limited | Wholesale & retail | 2025 |
| LR Photography Limited | Professional & scientific | 2025 |
| LSJ Aviation Ltd | Manufacturing | 2021 |
| LUBO2009 Ltd | Construction | 2013 |
| Luck Property Management Ltd | Real estate | 2018 |
| Lucky Doors Property Management Limited | Real estate | 2021 |
| Lucy Parker Consulting Ltd | Professional & scientific | 2016 |
| Lukandom Ltd | Administrative & support | 2022 |
| Luminous Edit Cosmetics Limited | Wholesale & retail | 2023 |
| Lunexa Trading Ltd | Wholesale & retail | 2025 |
| LUX Wedding Cars Ltd | Transport & logistics | 2025 |
| Luxary Homes Ltd | Real estate | 2021 |
| Luxorion Ltd | Professional & scientific | 2025 |
| Luxury by 1913 Ltd | Wholesale & retail | 2025 |
| LWB Consultancy Ltd | Professional & scientific | 2022 |
| Lync Consultancy Ltd. | Information & communication | 2014 |
| Lyndel Harrison Limited | Professional & scientific | 2023 |
| Lyndon Lightweight Structures Limited | Construction | 2025 |
| Lyzise Ltd | Professional & scientific | 2024 |
| M & P Silverwood Ltd | Transport & logistics | 2020 |
| M & S Tennessee Express Ltd | Hospitality | 2019 |
| M 2 E Trading Ltd | Wholesale & retail | 2024 |
| M Boga Ltd | Health & social care | 2023 |
| M Duden Ltd | Other services | 2024 |
| M G Fabrications Limited | Manufacturing | 2019 |
| M J Mcarthur Limited | Financial services | 2019 |
| M L BRA Ltd | Hospitality | 2026 |
| M R Kruger Ltd | Hospitality | 2025 |
| M Tejani Limited | Professional & scientific | 2015 |
| M V Malkin Limited | Professional & scientific | 2015 |
| M.E.L Ventures Ltd | Financial services | 2026 |
| M01 Property Ltd | Real estate | 2024 |
| MA Gaskin Holdings Ltd | Real estate | 2025 |
| MA1NTAIN Domestic & Property Ltd | Construction | 2023 |
| Maanudam Foundation | Health & social care | 2023 |
| Mabel Care Ltd | Health & social care | 2023 |
| Maboisacare Co Limited | Health & social care | 2017 |
| Madigas Maintenance Ltd | Professional & scientific | 2019 |
| MAG - Gardening & Landscaping Limited | Administrative & support | 2026 |
| Magna Carta Aviation Limited | Transport & logistics | 2018 |
| Magnetic Separations Limited | Professional & scientific | 1980 |
| Magnolia Court (Wallington) Residents Company Limited | Households | 1993 |
| Magsep Ltd | Extraterritorial | 2022 |
| Magzimum Metal Separations Limited | Professional & scientific | 2024 |
| Mahyar Limited | Real estate | 2026 |
| MAID2CLEAN (Croydon) Limited | Other services | 2004 |
| MAID2CLEAN (Reigate) Limited | Other services | 2006 |
| Maintenance South East Ltd | Administrative & support | 2022 |
| Maison DE Vera Ltd | Administrative & support | 2024 |
| Majestic Securities Limited | Professional & scientific | 2012 |
| Maka Engineering Services Limited | Construction | 2014 |
| Make My Move Limited | Transport & logistics | 2025 |
| Makerie Studio Ltd | Other services | 2015 |
| Makplace Ltd | Construction | 2021 |
| Malabe Consultants Ltd | Professional & scientific | 2025 |
| Malcolm Davenport Consulting Limited | Professional & scientific | 2019 |
| Malone Pike Limited | Professional & scientific | 2023 |
| Manage My French Property Limited | Professional & scientific | 2024 |
| Manak Footwear Europe Limited | Wholesale & retail | 2009 |
| Manat Enterprises Ltd | Other services | 2020 |
| Manatee Place Management Limited | Households | 1998 |
| Mangat Enterprises Ltd | Real estate | 2023 |
| Mangera Yvars Architects Limited | Professional & scientific | 2007 |
| Manocass Limited | Information & communication | 2012 |
| Manor Glass Limited | Administrative & support | 2007 |
| Manor House Management Company Limited | Households | 2016 |
| Mansard Manor RTM Company Limited | Households | 2010 |
| Maple Grove Business Centre Management Limited | Households | 2021 |
| Marak Ltd | Construction | 2026 |
| Mareen Business Ventures Limited | Health & social care | 2009 |
| Margarita Pearl Ltd | Administrative & support | 2008 |
| Mark Mitchener Limited | Other services | 2002 |
| Mark Smith Musical Director Limited | Information & communication | 2012 |
| Mark Storey Design Ltd | Professional & scientific | 2018 |
| Markvel Ltd | Wholesale & retail | 2024 |
| Marlow Wealth Management Limited | Financial services | 2012 |
| Marsack Holdings Limited | Real estate | 2015 |
| Marsack Properties Limited | Real estate | 2022 |
| Marshall’S Meadows Services Ltd | Administrative & support | 2024 |
| Martello Estates Limited | Professional & scientific | 2018 |
| Martelo Construction Ltd | Construction | 2025 |
| Martinez Property 1 Limited | Real estate | 2016 |
| Marval Property Limited | Households | 2011 |
| Mash MAN Clothing Ltd | Wholesale & retail | 2025 |
| Mash MAN Properties Ltd | Real estate | 2025 |
| Mash MAN Soft Ltd | Information & communication | 2018 |
| MASH101 Ltd | Administrative & support | 2018 |
| Master Touch Decorating Limited | Construction | 2020 |
| Masterklin Cleaning Limited | Construction | 2017 |
| Mastery of Flavour Ltd | Hospitality | 2021 |
| Mastons Ltd | Professional & scientific | 2023 |
| Maternally Fit Limited | Health & social care | 2006 |
| Mathew Kerwick Music Limited | Information & communication | 2015 |
| Matte Black Cafe Limited | Hospitality | 2023 |
| Matte Black Lounge Ltd | Hospitality | 2025 |
| Matthew J. Henry Ltd | Arts & recreation | 2015 |
| Maven Systems Limited | Information & communication | 2019 |
| MAX Building Ltd | Construction | 2025 |