| Monarch Acoustics Holdings Limited | Financial services | 2020 |
| Monarch Acoustics Limited | Manufacturing | 1987 |
| Monarch Inc. Energy Limited | Wholesale & retail | 2025 |
| Monarch Inc. Homes Limited | Real estate | 2023 |
| Monarch Inc. Limited | Health & social care | 2020 |
| Monarch Inc. Marketing and Communications Limited | Construction | 2024 |
| Monarch Vale Properties Ltd | Real estate | 2026 |
| Monarch Weddings & Events Ltd | Other services | 2023 |
| Monarchy Motors Ltd | Wholesale & retail | 2020 |
| Mond Pharmaceuticals Limited | Manufacturing | 2020 |
| Mondo BT Limited | Other services | 2025 |
| Mondottica Limited | Wholesale & retail | 2001 |
| Money Banq Limited | Financial services | 2010 |
| Money Muscle UK Limited | Wholesale & retail | 2016 |
| Money Whirl Limited | Real estate | 1999 |
| Moneymine Limited | Information & communication | 2025 |
| Moni Build Ltd | Construction | 2017 |
| Monica Dube Limited | Health & social care | 2013 |
| Monica Elaine Lindsay Ltd | Extraterritorial | 2024 |
| Monica's Caribbean Kitchen Limited | Hospitality | 2025 |
| Monish Co Limited | Hospitality | 2025 |
| Monitor of Things Ltd | Manufacturing | 2020 |
| Monitor Solutions Ltd | Real estate | 1996 |
| Monk Estates Limited | Real estate | 1991 |
| Monkey Business Arboriculture Limited | Agriculture & fishing | 2012 |
| Monkey Hill Media LLP | | 2021 |
| Monkey Troup Limited | Wholesale & retail | 2020 |
| Monkey Wrench Plumbing & Heating Ltd | Construction | 2021 |
| Monkfish Construction Management Ltd | Construction | 2019 |
| Monkie Limited | Extraterritorial | 2004 |
| Monk’S Place Aslockton Management Company Ltd | Real estate | 2023 |
| Monlog UK Ltd | Transport & logistics | 2018 |
| Monmos Nott Limited | Hospitality | 2026 |
| Mono Project Management Limited | Construction | 2003 |
| Mono Vehicle Logistics Ltd | Transport & logistics | 2025 |
| Monochrome Plating (Midlands) Ltd | Manufacturing | 2007 |
| Monocut Ltd | Manufacturing | 2018 |
| Monoverde Group Limited | Financial services | 2026 |
| Monoverde Plastics Ltd | Manufacturing | 2026 |
| Monoverde Sports Ltd | Wholesale & retail | 2026 |
| Monsal House Ltd | Households | 2025 |
| Monsal Securities Limited | Real estate | 2000 |
| Monsoon Books Ltd | Information & communication | 2016 |
| Monsta Events Ltd | Professional & scientific | 2022 |
| Monsta Nottingham Ltd | Professional & scientific | 2023 |
| Monster Screen Prints Limited | Manufacturing | 2005 |
| Monster Trucking Limited | Transport & logistics | 2013 |
| Montage Films Limited | Arts & recreation | 1985 |
| Montague House Group Ltd | Real estate | 2021 |
| Montana Shop (Nottingham) Limited | Administrative & support | 2011 |
| Montanari Court Residents Company Limited | Households | 2006 |
| Montane Technical Services Ltd | Manufacturing | 2015 |
| Montego Bay Bar Ltd | Hospitality | 2024 |
| Monterawatches Limited | Manufacturing | 2026 |
| Monterosso Ltd | Other services | 2012 |
| Montgomery and Charles Ltd | Manufacturing | 2025 |
| Montgomery Masters Ltd | Professional & scientific | 2006 |
| Montgomery North Ltd | Professional & scientific | 2011 |
| Montpelier 18 Limited | Real estate | 2018 |
| Montrose Group Ltd | Professional & scientific | 2022 |
| Montrose Property Group Ltd | Real estate | 2024 |
| Montrose Real Estate Ltd | Real estate | 2025 |
| Montypi Productions Ltd | Information & communication | 2026 |
| Monui Limited | Professional & scientific | 2020 |
| Monz 23 Limited | Professional & scientific | 2016 |
| Monza 2000 Ltd | Wholesale & retail | 2013 |
| Monza Builders Ltd | Construction | 2015 |
| Monza Homes Ltd | Construction | 2017 |
| MOO Haven Rescue | Agriculture & fishing | 2013 |
| MOO Property Ltd | Real estate | 2019 |
| Mooch Matcha Ltd | Hospitality | 2026 |
| Mood Barbers Limited | Other services | 2026 |
| Mood Bears Limited | Wholesale & retail | 2019 |
| Moon Bear Treats Ltd | Manufacturing | 2026 |
| Moon Diro Trading Ltd | Wholesale & retail | 2018 |
| Moona Kousar Ltd. | Health & social care | 2017 |
| Moonchild Films Ltd | Information & communication | 2022 |
| Moonicorns Ltd | Agriculture & fishing | 2021 |
| Moonlight Essence Limited | Wholesale & retail | 2025 |
| Moonlight Stitches Limited | Wholesale & retail | 2024 |
| Moons Property Services Limited | Real estate | 2025 |
| Moonshine Drinks Limited | Manufacturing | 2011 |
| Moonshot Group Ltd | Professional & scientific | 2017 |
| Moonstone Homes Ltd | Real estate | 2018 |
| Moonstruck Event Hire Ltd | Administrative & support | 2026 |
| Moontaste Limited | Real estate | 2021 |
| Moontown Limited | Manufacturing | 1996 |
| Moor Lionz TFT C.I.C. | Education | 2018 |
| Moor Logistics Limited | Transport & logistics | 2026 |
| Moorbridge Cyber Security Limited | Administrative & support | 2016 |
| Moorbridge Developments Limited | Construction | 2012 |
| Moore & Webb Limited | Construction | 2014 |
| Moore and Attlock Limited | Hospitality | 2023 |
| Moore Brokers Ltd | Professional & scientific | 2024 |
| Moore Engagement Limited | Administrative & support | 2023 |
| Moore Health Clinic Limited | Health & social care | 2013 |
| Moore Property Holdings & Investments Ltd | Real estate | 2019 |
| Moore Residential Property Ltd | Real estate | 2017 |
| Moore Sound Ltd | Information & communication | 2025 |
| Moores Nurseries & Garden Centre Limited | Wholesale & retail | 1998 |