| Mobile Poultry Farming Ltd | Professional & scientific | 2025 |
| Mobility Analytics Limited | Extraterritorial | 2017 |
| Mobius Properties Ltd | Real estate | 2020 |
| MOC Support Ltd | Manufacturing | 2022 |
| Mocell Limited | Wholesale & retail | 2023 |
| Moda Cambridge Limited | Other services | 2014 |
| Moda Mill Road Ltd | Other services | 2024 |
| Modann Limited | Professional & scientific | 2018 |
| MODE51 Software Ltd | Information & communication | 2020 |
| Modecarbon Limited | Professional & scientific | 2025 |
| Modere UK Limited | Administrative & support | 1992 |
| Modern Home Property Services Limited | Real estate | 2024 |
| Modern MO Ltd | Wholesale & retail | 2020 |
| Modest Cambridge Limited | Wholesale & retail | 2024 |
| Modica Holdings Ltd | Water & waste | 2024 |
| Modigliani Gourmet Ltd | Administrative & support | 2018 |
| Modivas Limited | Water & waste | 2025 |
| Modulo Research Ltd | Professional & scientific | 2022 |
| Mogrify Limited | Professional & scientific | 2016 |
| Mohala Growth Partners Ltd | Professional & scientific | 2024 |
| Mohammad Yazen Aljallad Co Ltd | Wholesale & retail | 2025 |
| Moir Business Services Limited | Information & communication | 2009 |
| Mojito Home Furnishing Co., Ltd | Manufacturing | 2021 |
| Mojo Exports and Imports Ltd | Manufacturing | 2025 |
| Moklads Meals Ltd | Hospitality | 2025 |
| Molecular Level Events Ltd | Administrative & support | 2022 |
| Molecular Photobiology Consulting Ltd | Professional & scientific | 2025 |
| Molecular Synthetics Limited | Professional & scientific | 2003 |
| Molscape Research Ltd | Professional & scientific | 2010 |
| Molten Films Ltd | Information & communication | 2023 |
| Molyon Limited | Professional & scientific | 2024 |
| Mom's Catering Ltd | Hospitality | 2025 |
| Momaliks Limited | Hospitality | 2019 |
| Momart Training Ltd | Education | 2023 |
| Momencraft Limited | Information & communication | 2019 |
| Momentous Therapeutics Ltd | Professional & scientific | 2022 |
| Momo Bellini Ltd | Hospitality | 2022 |
| Momo Housing Limited | Real estate | 2023 |
| Mon-Nes Property Ltd | Real estate | 2007 |
| Mon-Nes Retail Ltd | Wholesale & retail | 2015 |
| Monalink Ltd | Wholesale & retail | 2019 |
| Monarch Alarms Limited | Construction | 1993 |
| Monarch Court (Hampstead Garden Suburb) Management Limited | Households | 1976 |
| Monarch Court Freehold NO.1 Limited | Real estate | 2014 |
| Monarch Court Management Company Limited | Households | 2002 |
| Monavate Holdings Limited | Professional & scientific | 2020 |
| Monavate Ltd | Financial services | 2020 |
| Monay Materials Technology Ltd. | Extraterritorial | 2022 |
| Mondpackaging Ltd | Wholesale & retail | 2019 |
| Monetrix Ltd | Information & communication | 2025 |
| Money Builder Aviation Ltd | Manufacturing | 2024 |
| Moneymetrics Limited | Information & communication | 2014 |
| Moneymovr Limited | Information & communication | 2013 |
| Mongoose Hospitality Limited | Hospitality | 2024 |
| Monkbridge Limited | Real estate | 2024 |
| Monks Maintenance Limited | Construction | 2021 |
| Monksfield (Cambourne) Management Company Limited | Real estate | 2002 |
| Mono Cambridge Limited | Information & communication | 2018 |
| Monochrome Bars Limited | Hospitality | 2016 |
| Monocot Limited | Information & communication | 2024 |
| Monster Heating and Cooling Limited | Construction | 2011 |
| Montague Park (Shinfield) NO. 6 Management Limited | Households | 2004 |
| Montana Property Investments Limited | Households | 1990 |
| Montbron Construction Limited | Construction | 2020 |
| Montbron Limited | Construction | 2020 |
| Montclerc Ltd | Professional & scientific | 2020 |
| Montgomery Editions and Translations Limited | Professional & scientific | 2015 |
| Montgomery Stanton Limited | Construction | 2021 |
| Montlake Capital Limited | Financial services | 2018 |
| Montmorency Limited | Information & communication | 2011 |
| Montrehoboth Limited | Health & social care | 2012 |
| Montroy Ltd | Construction | 2015 |
| Monument Cycling Limited | Arts & recreation | 2017 |
| MOO to YOU Dairy Limited | Other services | 2017 |
| Mood Foods Ltd | Manufacturing | 2007 |
| Moodys World Ltd | Financial services | 2025 |
| Mooge Tech Group Co., Ltd | Extraterritorial | 2014 |
| Mooi Architecture Ltd | Professional & scientific | 2013 |
| Mooi Homes Ltd | Construction | 2025 |
| Moolahx Digital Solutions Ltd | Information & communication | 2025 |
| Moon & Sun Partners Limited | Wholesale & retail | 2025 |
| Moon Group Limited | Wholesale & retail | 2022 |
| Moonclash Foundation Ltd | Information & communication | 2026 |
| Mooncolony Limited | Professional & scientific | 2016 |
| Mooncrown Limited | Construction | 1988 |
| Moonexe Technology Ltd | Information & communication | 2025 |
| Mooney Composites Limited | Manufacturing | 2012 |
| Moonfield Investments Ltd | Real estate | 2021 |
| Moonhills Flats (Bracknell) Limited | Households | 1979 |
| Moonlight Private Hire Ltd | Transport & logistics | 2023 |
| Moonlight Sonata Investments Ltd | Wholesale & retail | 2018 |
| Moonshine Adventure Company Ltd | Hospitality | 2024 |
| Moonshine Brewery Cambridge Limited | Hospitality | 2013 |
| Moonx Limited | Professional & scientific | 2023 |
| Moor Health Care Ltd | Health & social care | 2023 |
| Moor Lane Management Company Limited | Households | 2002 |
| Moor Park (Guilden) Management Company Limited | Households | 2024 |
| Moore Media Ltd | Information & communication | 2025 |
| Moorearcanum Limited | Information & communication | 2024 |
| Mooreland Building Services Ltd | Construction | 2020 |