| Luke Cartwright Ltd | Information & communication | 2026 |
| Lumen Electrics Ltd | Construction | 2022 |
| LUX Infinity Ltd | Transport & logistics | 2025 |
| LUX London Projects Ltd | Transport & logistics | 2020 |
| Luxury Nails (Horley) Ltd | Other services | 2026 |
| Lyndieloos Limited | Health & social care | 2020 |
| Lynx Innovations Ltd | Information & communication | 2024 |
| M & H Transport Limited | Transport & logistics | 2008 |
| M K Gates & Joinery Ltd | Manufacturing | 2021 |
| M2KN Consulting Limited | Professional & scientific | 2011 |
| Macana Properties Ltd | Real estate | 2017 |
| Macher Distribution Limited | Professional & scientific | 2000 |
| Machin Property Holdings Limited | Real estate | 2017 |
| MAD Ideas Ltd | Administrative & support | 2010 |
| Madalaine Investment Ltd | Professional & scientific | 2012 |
| Madalaine Rose Ltd | Professional & scientific | 2020 |
| Made by Artisan Ltd | Manufacturing | 2024 |
| Maeve Trade Solutions Limited | Wholesale & retail | 2023 |
| MAGNITES27 Ltd | Hospitality | 2025 |
| Magpie (Surrey) Limited | Administrative & support | 2021 |
| Magpile Music Limited | Information & communication | 2007 |
| Maguire Maritime Consultants Limited | Professional & scientific | 2022 |
| MAI Caller Limited | Financial services | 2026 |
| Majestic Building Services Ltd | Construction | 2020 |
| Manners Construction Ltd | Construction | 2019 |
| Mannyblanks Ltd | Professional & scientific | 2019 |
| Mansell Mctaggart Horley Ltd | Real estate | 2014 |
| Manzyapp Ltd | Wholesale & retail | 2025 |
| Marame Ltd | Financial services | 2023 |
| Margaret Tully Limited | Education | 2013 |
| Marine and Yacht Surveys Limited | Transport & logistics | 2009 |
| Mark Taylor Motors Limited | Wholesale & retail | 1990 |
| Mark Vickers Properties Limited | Real estate | 2025 |
| Marked by Teachers Ltd | Education | 2021 |
| Marketman Marketing Limited | Administrative & support | 1987 |
| Markhz Airport Transfers Ltd | Transport & logistics | 2026 |
| Marley Groundwork’S Ltd | Construction | 2021 |
| Marnan Holdings Limited | Real estate | 1990 |
| Marron Gray Limited | Wholesale & retail | 2020 |
| Martin Joyce Developments Ltd | Construction | 2021 |
| Martin Joyce Holdings Ltd | Financial services | 2021 |
| Martin Joyce Limited | Construction | 1993 |
| Martin Joyce Property Investment Ltd | Real estate | 2021 |
| MAS Accountancy (Surrey) Limited | Professional & scientific | 2021 |
| MAS Accountancy South Limited | Administrative & support | 2024 |
| MAS STH Limited | Professional & scientific | 2025 |
| Master Boilers Limited | Construction | 2017 |
| Master Heating Services Ltd | Construction | 2006 |
| Matosi Homes Limited | Real estate | 2025 |
| MAX Transport Limited | Transport & logistics | 2010 |
| Maxlot Projects Ltd | Construction | 2023 |
| Mayhew Estates (Horley) Limited | Real estate | 2007 |
| Mayie Logistics Limited | Health & social care | 2023 |
| Maze CCM Ltd | Administrative & support | 2025 |
| MC Ecology Limited | Professional & scientific | 2020 |
| Mcall Consulting Ltd | Wholesale & retail | 2011 |
| MCC Services Gatwick Limited | Manufacturing | 2021 |
| Mccarthy Wright Holdings Ltd | Financial services | 2022 |
| Mccarthy Wright Property Ltd | Real estate | 2021 |
| Mccb Ltd | Households | 2015 |
| Mclove Productions Ltd | Information & communication | 2021 |
| Mcmc Limited | Real estate | 2024 |
| Mddr Ltd | Information & communication | 2025 |
| ME Motors Limited | Wholesale & retail | 2025 |
| Meab Diagnostics Limited | Health & social care | 2024 |
| Meatec Ltd | Manufacturing | 1984 |
| Meerkats Digital Media Limited | Information & communication | 1999 |
| Meldi Limited | Wholesale & retail | 2023 |
| Merch Solutions Limited | Professional & scientific | 2025 |
| Merco Group Holdings Limited | Financial services | 2022 |
| Metal Art Dessign Ltd | Manufacturing | 2023 |
| Metro Decon Limited | Construction | 2017 |
| Metro Deconstruction Ltd | Construction | 2017 |
| Metro Deconstruction Services Limited | Construction | 2005 |
| Metro Link Couriers Ltd | Water & waste | 2025 |
| Metrojoint Limited | Other services | 2022 |
| MH Property MIX Limited | Households | 2018 |
| MH2O Ltd | Professional & scientific | 2012 |
| Michelle Anders Ltd | Transport & logistics | 2026 |
| Micro Maintenance Limited | Information & communication | 2000 |
| Mighty Express Courier Services Ltd | Transport & logistics | 2025 |
| Mikkimens Venture Limited | Health & social care | 2022 |
| Milestones Accountancy Solutions (South) Limited | Professional & scientific | 2018 |
| Miliro Ltd | Professional & scientific | 2021 |
| Millennial Digital ERA Ltd | Wholesale & retail | 2018 |
| Miltons Fencing Ltd | Construction | 2022 |
| Mimzi Ltd | Professional & scientific | 2019 |
| Mind Forest Talking Therapies Ltd | Health & social care | 2023 |
| Mindex Limited | Wholesale & retail | 1984 |
| Mindview Limited | Information & communication | 2019 |
| Minerva MAY Limited | Education | 2023 |
| Minford Ltd | Other services | 2016 |
| Minnie-Mae Studio Ltd | Manufacturing | 2025 |
| Mirca Limited | Information & communication | 2020 |
| Mission: Planet Global Ltd | Financial services | 2023 |
| Mitbit Ltd | Real estate | 2024 |
| MJV Pensions Ltd | Financial services | 2020 |
| MKD Property Services Ltd | Real estate | 2024 |
| MKN Motorsports Limited | Wholesale & retail | 2019 |
| MKR Recovery (Thanet) Limited | Wholesale & retail | 2025 |