| Modesty Services Limited | Health & social care | 2015 |
| Modi Holdings Limited | Real estate | 2017 |
| Modular Mast Systems IP Limited | Administrative & support | 2018 |
| Modular Mast Systems Limited | Information & communication | 2022 |
| Moduline Construction & Fit-Out Limited | Construction | 2026 |
| Modulink Energy Limited | Administrative & support | 2023 |
| Modulyss UK Limited | Manufacturing | 2022 |
| Modus Vivendi the Residence (Leeds) Ltd | Real estate | 2023 |
| Moeesa Group Ltd | Wholesale & retail | 2023 |
| Moes Phone Shop Ltd | Manufacturing | 2026 |
| Moetvation Limited | Extraterritorial | 2022 |
| Moffelm Management Limited | Real estate | 2007 |
| Mofhart Limited | Financial services | 2016 |
| MOG Print Ltd | Manufacturing | 2021 |
| Moggerhanger Properties 2004 Limited | Other services | 2004 |
| Mohammed Sbahuddin Rafiuddin Investments Limited | Financial services | 2025 |
| Moja Properties Ltd | Construction | 2024 |
| Mokeet & Co Ltd | Real estate | 2026 |
| Moko MK Limited | Hospitality | 2018 |
| Mola Integrated Solutions Ltd | Other services | 2017 |
| Molal Healthcare Services Ltd | Real estate | 2020 |
| Molanza Holdings Ltd | Information & communication | 2021 |
| Molior Consultancy Ltd | Professional & scientific | 2014 |
| Moliv Design Services Ltd | Construction | 2018 |
| Molly's Pantry Ltd | Hospitality | 2020 |
| Molo Creative Limited | Professional & scientific | 2016 |
| Molosser Ltd | Manufacturing | 2025 |
| Molugu Tech Ltd | Information & communication | 2012 |
| Molvodi Limited | Professional & scientific | 2008 |
| Moma Foods Ltd. | Wholesale & retail | 2005 |
| Momed Ltd | Health & social care | 2023 |
| Moments Mentoring With Authentic Love CIC | Education | 2019 |
| Momma Bear Publishing Ltd | Professional & scientific | 2013 |
| Momyqa Limited | Real estate | 2025 |
| MON Jardin Capillaire Ltd | Wholesale & retail | 2022 |
| Mon-Luk Limited | Construction | 2023 |
| Mona Investment Ltd | Wholesale & retail | 2022 |
| Monalisa Health Ltd | Health & social care | 2025 |
| Monarch AI Labs Ltd | Professional & scientific | 2026 |
| Monarch Frame Ltd | Professional & scientific | 2026 |
| Monat Global UK Ltd | Wholesale & retail | 2017 |
| Monet Tree Care Limited | Agriculture & fishing | 2020 |
| Money Help Limited | Other services | 2016 |
| Money Right NOW Ltd | Other services | 2012 |
| Money Way Investment Limited | Real estate | 2020 |
| Money Whisperer Ltd | Administrative & support | 2021 |
| Moneywize Accountants Boston Limited | Administrative & support | 2019 |
| Moneywize Accountants Ltd | Professional & scientific | 2007 |
| Moneywize Accountants Peterborough Ltd | Administrative & support | 2022 |
| Moneywize Business Advisory Ltd | Financial services | 2022 |
| Monica's Maids Ltd | Administrative & support | 2025 |
| Monier (China) Holdings Limited | Professional & scientific | 1976 |
| Monier Limited | Extraterritorial | 2016 |
| Monks Property Investments Ltd | Real estate | 2024 |
| Monkston Barbers Ltd | Other services | 2025 |
| Monkston Community Centre and Sports Pavilion Limited | Real estate | 2001 |
| Mono Building Services Ltd | | 2009 |
| Monocle Solutions Limited | Professional & scientific | 2011 |
| Monofix Ltd | Professional & scientific | 2019 |
| Monopoly Assets Ltd | Real estate | 2021 |
| Monsii Limited | Administrative & support | 2009 |
| MONSTER1ST Ltd | Information & communication | 2020 |
| Monsti Ltd | Wholesale & retail | 2024 |
| Monstrous Attire Ltd | Wholesale & retail | 2026 |
| Monta Services UK Limited | Transport & logistics | 2024 |
| Montage Moments Memorabilia Limited | Wholesale & retail | 2022 |
| Montblanc Consultant Ltd | Administrative & support | 2024 |
| Montevia Group Ltd | Administrative & support | 2024 |
| Montpanasse Limited | Manufacturing | 2013 |
| Monument House LLP | | 2016 |
| Monzur Investments Limited | Information & communication | 2015 |
| Mooboo Retail Empat Limited | Hospitality | 2019 |
| Mood Corporation Limited | Financial services | 2024 |
| Moodestore Ltd | Wholesale & retail | 2023 |
| Moodley Dental Practice Limited | Health & social care | 2019 |
| Moodlifestyle Ltd | Wholesale & retail | 2019 |
| Moodycow Nails Ltd | Other services | 2022 |
| Moon and Stars Yoga Ltd | Health & social care | 2024 |
| Moon's Couture Ltd | Wholesale & retail | 2019 |
| Moonbow Media Limited | Other services | 2017 |
| Moonbow World Limited | Education | 2018 |
| Mooncity Properties Limited | Real estate | 2024 |
| Mooncomputers Limited | Information & communication | 2002 |
| Mooney's Mobile Chipping Ltd | Water & waste | 2025 |
| Moonfare UK Limited | Financial services | 2021 |
| Moonlight Partners Trading Ltd | Administrative & support | 2025 |
| Moor House Hereford Limited | Real estate | 2016 |
| Moorbeth Luxury Ltd | Wholesale & retail | 2026 |
| Moore Fisher Holdings Limited | Financial services | 2022 |
| Moore Growth Accountants LLP | | 2015 |
| Moore Quality Engineering Ltd | Information & communication | 2026 |
| Moorland Private Senior School Ltd | Education | 2023 |
| Moose Fashions UK Limited | Wholesale & retail | 2021 |
| Morais Ltd | Wholesale & retail | 2025 |
| Moran Civil Consulting Ltd | Professional & scientific | 2025 |
| Mordor Labs Ltd | Extraterritorial | 2024 |
| Mordros Properties Limited | Hospitality | 2023 |
| Mordziaty Trans Ltd | Transport & logistics | 2019 |
| More Control (U.K.) Limited | Manufacturing | 1998 |
| More Control Limited | Manufacturing | 2006 |