| Molecare Ltd | Information & communication | 2024 |
| Molecule Regulatory Services Limited | Administrative & support | 2012 |
| Moley.Tv Ltd | Professional & scientific | 2011 |
| Molinaro & Molinaro Ltd | Administrative & support | 2017 |
| Molinero 2010 Ltd | Administrative & support | 2010 |
| Molinse Ltd | Other services | 2024 |
| Mollie Borg Consultancy Limited | Professional & scientific | 2022 |
| Mollie Maes Distinctive Furnishings Ltd | Wholesale & retail | 2019 |
| Mollobby Limited | Real estate | 2025 |
| Molly's Diner Ltd | Hospitality | 2019 |
| Molly's World C.I.C. | Information & communication | 2014 |
| Molont Limited | Manufacturing | 2015 |
| Molvi Basheer Ltd | Wholesale & retail | 2025 |
| Molwin Developments Limited | Wholesale & retail | 1954 |
| Mom's Own Milk Ltd | Manufacturing | 2015 |
| Momentum Bioscience Limited | Manufacturing | 2005 |
| Momentum Europe Group Ltd | Financial services | 2016 |
| Momentum Holding Ltd | Information & communication | 2025 |
| Momentum Motor Works Cardiff Limited | Wholesale & retail | 2025 |
| Momentummindz Ltd | Professional & scientific | 2025 |
| Momentumxo Ltd | Professional & scientific | 2005 |
| Momo Media Group Limited | Professional & scientific | 2019 |
| Momo's Yard Limited | Wholesale & retail | 2020 |
| Momoduoyaole and SON Limited | Health & social care | 2016 |
| Momoh Phone Ltd | Information & communication | 2024 |
| Momokoala Co., Ltd | Wholesale & retail | 2021 |
| Momoo Limited | Wholesale & retail | 2022 |
| MON Petit Chien Ltd | Wholesale & retail | 2017 |
| MON Property Services Limited | Real estate | 2019 |
| Mona Kamau Limited | Professional & scientific | 2018 |
| Monaco Holdings Limited | Real estate | 2020 |
| Monaco Property Holdings Limited | Real estate | 2021 |
| Monaksh Properties Limited | Real estate | 2024 |
| Monal Patel Ltd | Health & social care | 2023 |
| Monarch & Morrow Tech Limited | Professional & scientific | 2025 |
| Monarch Cleaning Services Ltd | Other services | 2019 |
| Monarch Living Limited | Households | 2025 |
| Monarch Systems International (MSI) Holding Ltd | Wholesale & retail | 2024 |
| Monark Websells Ltd | Wholesale & retail | 2025 |
| Monay Limited | Professional & scientific | 2003 |
| Moncon Ltd | Information & communication | 2020 |
| Mondays Only Ltd | Wholesale & retail | 2026 |
| Mondego Engineering Limited | Professional & scientific | 2019 |
| Mondello Ltd | Hospitality | 2019 |
| Mone Group Limited | Construction | 2023 |
| Moneta International Limited | Professional & scientific | 2006 |
| Monetae CS Limited | Professional & scientific | 2026 |
| Monetae Group Limited | Professional & scientific | 2019 |
| Monetise Global Ltd | Information & communication | 2019 |
| Monetise Group Ltd | Information & communication | 2022 |
| Monexa Limited | Financial services | 2025 |
| Monexo Solutions Ltd | Administrative & support | 2020 |
| Money Capital Ltd | Education | 2018 |
| Money Come on E-Commerce Ltd | Wholesale & retail | 2025 |
| Money Converters Ltd | Wholesale & retail | 2024 |
| Money for Nothing UK Limited | Arts & recreation | 2024 |
| Money in Motion Ltd | Education | 2024 |
| Money Management Training Ltd | Professional & scientific | 2019 |
| Money Mattaz Limited | Manufacturing | 2017 |
| Money Save Marketing Ltd | Public administration | 2019 |
| Money Saviour C.I.C. | Health & social care | 2011 |
| Money Saviour Financial Solutions Ltd | Education | 2012 |
| Money Savvy Kids Ltd | Education | 2026 |
| Moneypenny Utilities Ltd | Agriculture & fishing | 2018 |
| Moneypower International Inc Ltd | Information & communication | 2012 |
| Moneyvault Ltd | Financial services | 2025 |
| Moneywiseconveyancing Ltd | Professional & scientific | 2019 |
| Monfreid & FRY Ltd | Education | 2013 |
| Monico Garage Limited | Wholesale & retail | 2008 |
| Monika Smigiel Nail Art Ltd | Other services | 2025 |
| Monikh Limited | Other services | 2019 |
| Monily Inovations Ltd | Information & communication | 2024 |
| Monk Racing Ltd | Manufacturing | 2000 |
| Monkascare Limited | Health & social care | 2016 |
| Monkey Media Solutions Limited | Information & communication | 2012 |
| Monkey Philo Ltd | Information & communication | 2025 |
| Monkey Puzzler Business Solutions Ltd | Professional & scientific | 2015 |
| Monkeyboy Trading Ltd | Wholesale & retail | 2026 |
| Monkeyrocks Comics Limited | Wholesale & retail | 2024 |
| Monkeytots Ltd | Wholesale & retail | 2017 |
| Monks & Kaye Property Ltd | Real estate | 2020 |
| Monkston Properties Limited | Real estate | 2003 |
| Monmi Ltd | Wholesale & retail | 2025 |
| Monmouth Music Festival Limited | Administrative & support | 2009 |
| Monnow Construction Company Limited | Construction | 1971 |
| Monnow Media Limited | Professional & scientific | 2014 |
| Mono Automotive Ltd | Wholesale & retail | 2019 |
| Monochain Ltd | Information & communication | 2018 |
| Monocle Market Limited | Wholesale & retail | 2025 |
| Monolith Audio Ltd | Wholesale & retail | 2016 |
| Monolith Capital Limited | Wholesale & retail | 2022 |
| Monolith Consulting Limited | Information & communication | 2013 |
| Monolith Web Solutions Limited | Information & communication | 2016 |
| Monolo Property Limited | Real estate | 2024 |
| Monolux Invest L.P. | | 2017 |
| Monotonic Investments Ltd | Real estate | 2017 |
| Monotonic Limited | Information & communication | 2014 |
| Monsard Corporation PC | | 2017 |
| Monstertv Ltd | Other services | 2024 |
| Mont Blanc Logic Limited | Information & communication | 2025 |