| MKS Residential Ltd | Construction | 2024 |
| ML Property Sourcing Ltd | Real estate | 2026 |
| MLB Additive Manufacturing Ltd | Manufacturing | 2025 |
| MLB Limited | Other services | 2003 |
| MLL Developments Limited | Real estate | 2024 |
| MLM Promotions Ltd | Administrative & support | 2011 |
| MMA Homes Ltd | Construction | 2010 |
| MMP Real Estate Ltd | Real estate | 2026 |
| MNR Groundworks Ltd | Administrative & support | 2021 |
| Mo's Sons Properties Limited | Real estate | 2024 |
| Moat Place Ltd | Households | 2021 |
| Moat Rise Management Company Limited | Households | 1987 |
| Mobile & Vape Station Limited | Wholesale & retail | 2021 |
| Mobile Junction 21 Ltd | Wholesale & retail | 2025 |
| Mobile Kitchens Limited | Administrative & support | 1996 |
| MOBILEINTERNET2GO Ltd. | Information & communication | 2011 |
| Modelinkcad Services Limited | Professional & scientific | 2012 |
| Modelling Engineering & Development Company Limited | Construction | 1992 |
| Moderncultureclothes Limited | Wholesale & retail | 2025 |
| Modernglide Ltd | Construction | 2015 |
| Modus Learning Services Ltd | Professional & scientific | 2020 |
| MOG Management Ltd | Households | 2024 |
| Moghle Limited | Financial services | 2013 |
| Moja Vision Ltd | Professional & scientific | 2015 |
| Mojiico Limited | Professional & scientific | 2024 |
| Mole Limited | Construction | 2017 |
| Molthur Ltd | Wholesale & retail | 2023 |
| Monenti Ltd | Arts & recreation | 2018 |
| Mongrel Creative Ltd | Professional & scientific | 2020 |
| Mongrell Ltd | Wholesale & retail | 2025 |
| Monica Residence Limited | Real estate | 2026 |
| Monocle Insights Ltd | Professional & scientific | 2024 |
| Monson Limited | Hospitality | 2018 |
| Montague Managment Holdings Ltd | Professional & scientific | 2018 |
| Monte Darlo Limited | Information & communication | 2026 |
| Montgo Studios Ltd | Information & communication | 2025 |
| Monty Wilson Props Limited | Information & communication | 2011 |
| Monvi Homes Limited | Real estate | 2019 |
| Moobry Productions Limited | Arts & recreation | 2014 |
| Moocoa Ltd | Manufacturing | 2025 |
| Moor Lane (Woking) Management Company Limited | Households | 2015 |
| Moore House Cocktail Company Ltd | Wholesale & retail | 2020 |
| MOORO66 Ltd | Financial services | 2012 |
| Moorview Developers Ltd | Construction | 2015 |
| Moorview Holdings Ltd | Real estate | 2020 |
| Moosee Tasty Ltd | Wholesale & retail | 2019 |
| Moral International Ltd | Wholesale & retail | 2024 |
| Morco Construction Ltd | Construction | 2024 |
| More Than Muscle Limited | Other services | 2015 |
| Morgan Archway Ltd | Information & communication | 2015 |
| Morgan Cargo Ltd | Transport & logistics | 1999 |
| Morley Associates Ltd | Professional & scientific | 2023 |
| Morleys Portsmouth Limited | Hospitality | 2025 |
| Morprime Industries Ltd | Professional & scientific | 2021 |
| Morritt Engineering Limited | Professional & scientific | 2010 |
| Morse and Hound Limited | Wholesale & retail | 2020 |
| Morter Ltd | Construction | 2018 |
| Mosupi Ltd | Health & social care | 2025 |
| MOT Bros Ltd | Wholesale & retail | 2020 |
| Motion Applied Limited | Manufacturing | 1988 |
| Motion Pulse Limited | Wholesale & retail | 2022 |
| Motive Agency Limited | Professional & scientific | 2019 |
| Motor City Archives Ltd | Wholesale & retail | 2025 |
| Motor Race Consultants Limited | Administrative & support | 2023 |
| Motorcare (Woking) Ltd | Wholesale & retail | 2008 |
| Motorcare Car Sales Limited | Wholesale & retail | 2019 |
| Mottainai Solutions Ltd | Professional & scientific | 2023 |
| Mottsons Ltd | Extraterritorial | 2023 |
| Mouk Logistics Ltd | Transport & logistics | 2025 |
| Mount Street Management Services 2012 Limited | Extraterritorial | 2012 |
| Mountroyal Services Limited | Professional & scientific | 1991 |
| Moustro Developments Limited | Professional & scientific | 2004 |
| Moves Fitness Ltd | Other services | 1982 |
| Movevia Limited | Transport & logistics | 2026 |
| Mowgli Holding Limited | Financial services | 2025 |
| Mo`S Sons Limited | Construction | 2007 |
| MP Managerial Services Ltd | Construction | 2015 |
| Mp-Logistick Ltd | Transport & logistics | 2015 |
| MPA Mobile Auto Locksmith Ltd | Other services | 2026 |
| MPS Consultants Limited | Administrative & support | 2015 |
| MR Mcginty Ltd | Real estate | 2002 |
| MR Sher's Ice Cream Surrey & London Ltd | Wholesale & retail | 2022 |
| MR. Jewellers Ltd | Extraterritorial | 2019 |
| Mrab Limited | Wholesale & retail | 2025 |
| MRD Design Engineering Limited | Administrative & support | 2014 |
| Mredits Ltd | Professional & scientific | 2025 |
| MRH Hospitality Ltd | Wholesale & retail | 2025 |
| Mrmorris Ltd | Professional & scientific | 2018 |
| MRS Brickwork Ltd | Construction | 2024 |
| MRS Management U.K. Limited | Other services | 2021 |
| MRS. Keto Limited | Manufacturing | 2017 |
| MS Taxis Limited | Transport & logistics | 2019 |
| MSC Cruises Limited | Administrative & support | 1994 |
| MSE Developments Limited | Real estate | 2025 |
| MSG SS Holdings Limited | Financial services | 2022 |
| MSM Property Investment Limited | Real estate | 2021 |
| MST Events & TRI2O Limited | Arts & recreation | 2013 |
| MT Concepts INT Limited | Hospitality | 2025 |
| MTB Props Limited | Other services | 2011 |
| Mtbee Ltd | Manufacturing | 2017 |