| Monte Carlo Parks Ltd | Real estate | 2017 |
| Monte Forte Dorking Limited | Hospitality | 2025 |
| Monte Forte Events Limited | Hospitality | 2022 |
| Monte Forte Farnham Limited | Hospitality | 2023 |
| Monte Forte Holdings Limited | Hospitality | 2019 |
| Monte Forte Horsham Limited | Hospitality | 2019 |
| Monte Forte Reigate Limited | Hospitality | 2016 |
| Montera FX Consultants Limited | Professional & scientific | 2025 |
| Montrose Homecare Ltd | Health & social care | 2023 |
| Monty's Kickers LLP | | 2022 |
| Monynut Properties Limited | Real estate | 1986 |
| Moomin Merchandise Ltd | Manufacturing | 2013 |
| Moon Tree Developments Limited | Construction | 2013 |
| Moon Tree Esher Limited | Real estate | 2021 |
| Moonlander Limited | Professional & scientific | 2016 |
| Moonlight Perfumes Ltd | Wholesale & retail | 2025 |
| Moonsgate Limited | Real estate | 2000 |
| Mordaunt Group Limited | Hospitality | 2025 |
| More Layers Ltd | Information & communication | 2025 |
| Morgans Airport Services Ltd | Manufacturing | 2016 |
| Morgans Investments Ltd | Financial services | 2023 |
| Morgans Management Ltd | Professional & scientific | 2023 |
| Morley IT Solutions Limited | Information & communication | 2001 |
| Morloch Limited | Professional & scientific | 2009 |
| Morrado House Limited | Wholesale & retail | 2025 |
| Morris Lights Ltd | Wholesale & retail | 2025 |
| Moss Building Ltd | Construction | 2024 |
| Moss Vitals Limited | Wholesale & retail | 2024 |
| MOT Juice Ltd | Information & communication | 2014 |
| Motherpride Limited | Wholesale & retail | 2025 |
| Motion Flight Techniques Limited | Education | 2026 |
| Motive Corp Ltd | Information & communication | 2025 |
| Motogalleria Ltd | Wholesale & retail | 2019 |
| Motor Gate Ltd | Wholesale & retail | 2024 |
| Motorworks Crawley Ltd | Wholesale & retail | 2025 |
| Move Faster Limited | Information & communication | 2025 |
| Movosoft Limited | Information & communication | 2021 |
| Movva Ltd | Education | 2025 |
| Moyo Holdings Ltd | Financial services | 2024 |
| MP Decorating & Maintenance Limited | Construction | 2025 |
| MP Serv Limited | Wholesale & retail | 2003 |
| Mpdcars Ltd | Transport & logistics | 2025 |
| Mpiloenhle Ltd | Health & social care | 2024 |
| Mpit Global Ltd | Information & communication | 2019 |
| MR and MRS Claus Limited | Arts & recreation | 2023 |
| MR and MRS Deeley Ltd | Wholesale & retail | 2025 |
| MR B'S Trees Ltd | Agriculture & fishing | 2026 |
| MR Executive Chauffeurs Ltd | Transport & logistics | 2024 |
| MR Exotic Frutis Limited | Wholesale & retail | 2025 |
| MR Invest Ltd | Wholesale & retail | 2011 |
| Mrbd | Other services | 2013 |
| MRC Consultancy Services Ltd | Professional & scientific | 2025 |
| Mrich Healthcare Limited | Health & social care | 2022 |
| Mrjdn Property Ltd | Real estate | 2026 |
| Mrmagicman Ltd | Transport & logistics | 2014 |
| MRT Events Ltd | Hospitality | 2021 |
| MS and ARC Limited | Transport & logistics | 2024 |
| MS Grow Ltd | Wholesale & retail | 2025 |
| MS Herrig Ltd | Transport & logistics | 2023 |
| MS Tech Services Ltd | Information & communication | 2018 |
| MSG Contractors (UK) Limited | Construction | 2013 |
| MSM Computer Services Limited | Information & communication | 2003 |
| MSM Gatwick Cars Ltd | Transport & logistics | 2026 |
| Msrg Logistics Limited | Transport & logistics | 2026 |
| Mtdgrow Ltd | Wholesale & retail | 2025 |
| MTR Investments Limited | Professional & scientific | 2011 |
| MTZ Services Ltd | Transport & logistics | 2019 |
| Mugiwarauchihatcg Ltd | Wholesale & retail | 2026 |
| Mukagasana Ltd | Health & social care | 2025 |
| Mukoyij Limited | Health & social care | 2015 |
| Multi Industry Training Awards Limited | Education | 2023 |
| Munro and SON Limited | Construction | 2025 |
| Muntean Delivery 247 Ltd | Transport & logistics | 2021 |
| Muran Limited | Health & social care | 2010 |
| Murati Ltd | Construction | 2018 |
| Musaja Construction Group Ltd | Construction | 2026 |
| Musariri Enterprises Ltd | Health & social care | 2019 |
| Musq Ltd | Administrative & support | 2024 |
| Musthafa Removals Limited | Transport & logistics | 2020 |
| Muwos Investments Limited | Administrative & support | 2016 |
| MV Gatwick Popinn Ltd | Hospitality | 2018 |
| Mwautomoto Ltd | Other services | 2016 |
| MWD Investments Ltd | Financial services | 2025 |
| MWR Services Ltd | Administrative & support | 2025 |
| My Brand Events Limited | Other services | 2019 |
| My Cabbage Limited | Transport & logistics | 2023 |
| My Cars Sussex Ltd | Transport & logistics | 2020 |
| My JOB Ltd | Administrative & support | 2018 |
| Mycos Services Limited | Professional & scientific | 2010 |
| Myhealthai Limited | Health & social care | 2025 |
| Myla’S Merch Ltd | Wholesale & retail | 2025 |
| Myres Global Group Ltd | Wholesale & retail | 2022 |
| Myrna Limited | Manufacturing | 1992 |
| Myrna Trading Holdings Limited | Financial services | 2020 |
| MYS Leya Ltd | Transport & logistics | 2025 |
| Myvoinic Services Ltd | Transport & logistics | 2024 |
| Mzei Limited | Transport & logistics | 2020 |
| N & S Consultancy Services Limited | Professional & scientific | 2016 |
| N & S Vani Limited | Wholesale & retail | 2019 |
| N Care Service Ltd | Health & social care | 2026 |