| Monihas Limited | Public administration | 2026 |
| Monika Kiss Hair & Beauty Ltd | Other services | 2023 |
| Monique Spokes Psychotherapy Limited | Health & social care | 2025 |
| Monir Ronald Geagea Ltd | Information & communication | 2016 |
| Monkaben Limited | Health & social care | 2019 |
| Monkal Ltd | Professional & scientific | 2023 |
| Monkey Business Design Limited | Administrative & support | 2014 |
| Monkey C Ltd | Extraterritorial | 2026 |
| Monkey Tree Events Ltd | Hospitality | 2024 |
| Monkey Tribe Limited | Construction | 2023 |
| Monkeypost Ltd | Other services | 2017 |
| Monkton Design Services Limited | Professional & scientific | 2012 |
| Monmouth Court (Management Company) Limited | Professional & scientific | 2008 |
| Monmouth Facilities Limited | Real estate | 2004 |
| Monolith Performance Ltd | Professional & scientific | 2025 |
| Monolith Visuals Limited | Professional & scientific | 2017 |
| Monomoon Ltd | Information & communication | 2016 |
| Monopoly Mgmt Limited | Arts & recreation | 2023 |
| Monroe York Estates Ltd | Hospitality | 2025 |
| Monroe's Hair Nails and Beauty Limited | Other services | 2013 |
| Monroes Training Academy Ltd | Education | 2020 |
| Monroeville Ltd | Professional & scientific | 2012 |
| Monrooh Limited | Wholesale & retail | 2024 |
| Monsiso Ltd | Other services | 2021 |
| Monster Dent Ltd | Wholesale & retail | 2020 |
| Monster Fireworks Ltd | Wholesale & retail | 2009 |
| Monster Gear Properties Ltd | Construction | 2026 |
| Monster Gear Rentals Ltd | Administrative & support | 2025 |
| Monster IT Services Ltd | Information & communication | 2013 |
| Monster Sites Limited | Professional & scientific | 2024 |
| Monsterbash CIC | Public administration | 2025 |
| Monsterful Limited | Information & communication | 2014 |
| Monsteromnibus Ltd | Information & communication | 2026 |
| Mont Blanc Partners Limited | Construction | 2013 |
| Mont KIA Development Limited | Construction | 2016 |
| Montagu Mews North (Freehold) Limited | Households | 2018 |
| Montague 40957 Limited | Hospitality | 2024 |
| Montague Court Management Limited | Households | 1981 |
| Montalt Training and Consultancy Ltd | Professional & scientific | 2023 |
| Montana Studios Limited | Arts & recreation | 2007 |
| Monte Rosso New Media Limited | Information & communication | 2024 |
| Monteray Central Ltd | Construction | 2025 |
| Montes Properties Limited | Real estate | 2014 |
| Montessori Services Ltd | Education | 2005 |
| Montessori ST Nicholas Ltd | Education | 1954 |
| Montgomerie Limited | Professional & scientific | 2006 |
| Montgomery COX Associates Ltd | Professional & scientific | 2002 |
| Montgomery Enterprises Limited | Professional & scientific | 2008 |
| Montgomery Lane Limited | Financial services | 2026 |
| Monthouse Ltd | Professional & scientific | 2026 |
| Monti Hats Limited | Wholesale & retail | 2026 |
| Montiecare Ltd | Health & social care | 2022 |
| Montpelier Business Park Trading Estate Management Company Limited | Administrative & support | 2003 |
| Montpelier Enterprises Ltd | Real estate | 2019 |
| Montpelier Local Ltd | Wholesale & retail | 2019 |
| Montpelier Organic Foods Ltd | Wholesale & retail | 2025 |
| Montpelier Potters Co-Operative Ltd | Manufacturing | 2025 |
| Montpelier View House Limited | Households | 2017 |
| Montpellier Apartments Limited | Construction | 2015 |
| Montpellier Developments Ltd | Real estate | 2020 |
| Montrelle Ltd | Wholesale & retail | 2026 |
| Montreux House James Street West Bath Management Company Limited | Households | 2008 |
| Montreux House ST. George Bristol Management Limited | Households | 1989 |
| Montrose Avenue Management Company Limited | Real estate | 2000 |
| Montuori Ltd | Hospitality | 2018 |
| Monty Wines Ltd | Wholesale & retail | 2006 |
| Monument View Management Services Limited | Real estate | 2005 |
| MOO Co 1 Limited | Financial services | 2024 |
| MOO Co 2 Limited | Financial services | 2024 |
| MOO Co 3 Limited | Financial services | 2024 |
| MOO Co 4 Limited | Financial services | 2025 |
| Mood Balloons Ltd | Administrative & support | 2015 |
| Moodster Ltd | Construction | 2012 |
| Moon Consulting Limited | Professional & scientific | 2001 |
| Moon Design (Bristol) Limited | Professional & scientific | 2021 |
| Moon Developments Limited | Construction | 2002 |
| Moon Festival Ltd | Arts & recreation | 2024 |
| Moon Home Developments Ltd | Construction | 2019 |
| Moon Media Ltd | Professional & scientific | 2007 |
| Moon Paws SOS Rescue & Rehome Ltd | Other services | 2025 |
| Moon Taxi Rentals Ltd | Administrative & support | 2019 |
| Moon Workshop Limited | Manufacturing | 2008 |
| MOON6 Ltd | Information & communication | 2024 |
| Moona Beauty Salon Ltd | Other services | 2017 |
| Moonage Media Ltd | Professional & scientific | 2014 |
| Moonchild Modifications Bristol Ltd | Other services | 2026 |
| Moonchild Modifications LLP | | 2023 |
| Moondance Limited | Hospitality | 2026 |
| Moondust BDZ Limited | Information & communication | 2020 |
| Moonflames.Uk Ltd | Extraterritorial | 2023 |
| Moonlight Care Services Limited | Administrative & support | 2013 |
| Moonlight Electrical Ltd | Construction | 2017 |
| Moonlight Mage Ltd | Extraterritorial | 2026 |
| Moonraker 2017 Ltd | Administrative & support | 2017 |
| Moonraker Ventures Limited | Professional & scientific | 2003 |
| Moonraker VFX Limited | Professional & scientific | 2014 |
| Moonrakers Software Limited | Information & communication | 2025 |
| Moonrider Films Ltd | Information & communication | 2022 |
| Moonrise Ltd | Information & communication | 2022 |
| Moonsprout Ltd | Wholesale & retail | 2024 |