| Modern Love Limited | Health & social care | 2020 |
| Modern Touch Nails HB Ltd | Other services | 2026 |
| Modify Construction Ltd | Construction | 2014 |
| Modify Dave Limited | Professional & scientific | 2026 |
| Modify JAY Limited | Professional & scientific | 2026 |
| Modify Plumbing & Heating Limited | Construction | 2026 |
| Modiqa Ltd | Professional & scientific | 2026 |
| Moduit Limited | Information & communication | 2016 |
| Moffatt Electrical Ltd | Construction | 2019 |
| Mofisi Ltd | Administrative & support | 2017 |
| Mogan Threads Ltd | Wholesale & retail | 2025 |
| MOH Carpentry & Sealants Limited | Construction | 2026 |
| Mojo Collective Ltd | Health & social care | 2025 |
| Molal Beem Limited | Health & social care | 2022 |
| Molarex Ltd | Information & communication | 2010 |
| Mold TIM Electrical Limited | Construction | 2014 |
| Moldovita Ltd | Construction | 2015 |
| Molly Eldridge Consulting Ltd | Financial services | 2021 |
| Molony Media Consulting Limited | Professional & scientific | 2012 |
| Momentum 20 Ltd | Hospitality | 2022 |
| Momo & More Ltd | Hospitality | 2026 |
| Momosh Food Box Ltd | Hospitality | 2022 |
| Momosh Ltd | Wholesale & retail | 2021 |
| Mona Architecture Ltd | Professional & scientific | 2022 |
| Monaghan Civil Engineering Limited | Construction | 2009 |
| Monago Resources Limited | Education | 2023 |
| Monarb Limited | Agriculture & fishing | 2018 |
| Monarch Ascend Investments Ltd | Real estate | 2026 |
| Monarch Cleaners (Springfield) Limited | Administrative & support | 2003 |
| Mondo Property Investments Ltd | Real estate | 2021 |
| Moneta Sapiens Ltd | Information & communication | 2023 |
| Moneymaster (Harlow) Ltd | Wholesale & retail | 2021 |
| Monkbell Limited | Real estate | 2008 |
| Monkey Bizness Group Limited | Arts & recreation | 2011 |
| Monkey Bizness Play Limited | Arts & recreation | 2011 |
| Monkey Mind Group Ltd | Wholesale & retail | 2019 |
| Monkey Park Investments Limited | Real estate | 2019 |
| Monkeyshine Limited | Information & communication | 2017 |
| Monkeysource Ltd | Information & communication | 2011 |
| Monkistuff Ltd | Wholesale & retail | 2014 |
| Monks Farm Developments Ltd | Financial services | 2018 |
| Monks Fish Limited | Wholesale & retail | 2025 |
| Monks Road (Earls Colne) Residents Management Company Limited | Households | 2018 |
| Monocle Media Ltd | Information & communication | 2015 |
| Monso Music Ltd | Information & communication | 2024 |
| Monster MAN Engineering Ltd | Construction | 2017 |
| Montagu Property Services London Ltd | Construction | 2015 |
| Montagu SW Developments Ltd | Real estate | 2016 |
| Monteagle Wealth Management Limited | Financial services | 2022 |
| Montgomery Capital Cambridge Limited | Financial services | 2024 |
| Monthind Clean Limited | Administrative & support | 2019 |
| Monthind Holdings Limited | Financial services | 1998 |
| Montrose Gardens Management Limited | Administrative & support | 2025 |
| Montrose House Ltd | Administrative & support | 2005 |
| Montsea Leisure Limited | Arts & recreation | 2021 |
| Monumental INK Ipswich Ltd | Other services | 2019 |
| Monumental INK Limited | Other services | 2013 |
| Moon Corporation Ltd | Wholesale & retail | 2025 |
| Moon Mountain Projects Ltd | Construction | 2021 |
| Moonlight Hollow Limited | Agriculture & fishing | 2006 |
| Moorcroft Brickwork Limited | Construction | 2014 |
| Moore About Homes Ltd | Professional & scientific | 2025 |
| Moore Bros 1815 LLP | | 2010 |
| Moore'Ish Crumpets Limited | Hospitality | 2021 |
| Moore'Ish London Limited | Hospitality | 2021 |
| Moores Commercial Cleaning Ltd | Administrative & support | 2014 |
| Moorside Nine Limited | Other services | 2014 |
| Moozy Limited | Information & communication | 2007 |
| MOP Limited | Information & communication | 2021 |
| Mopris Services Ltd | Extraterritorial | 2024 |
| Moqmo Ltd | Information & communication | 2019 |
| More Boost More Problems Ltd | Wholesale & retail | 2024 |
| More Logistics Limited | Transport & logistics | 2020 |
| More Plumbing & Heating Limited | Construction | 2016 |
| Morealigned Ltd | Arts & recreation | 2025 |
| Morehen Performance Limited | Professional & scientific | 2020 |
| Moreshwar Realty Ltd | Real estate | 2025 |
| Moreton Bay Management Company Limited | Households | 2021 |
| Moreways Land and Property Services Ltd | Real estate | 2025 |
| Morgan Engineering Consultants Limited | Professional & scientific | 2016 |
| Morgan Marine Holdings Limited | Financial services | 2018 |
| Morgan Mitchell Limited | Hospitality | 2024 |
| Morgan Sloane Limited | Professional & scientific | 2012 |
| Morgan's Consultancy Ltd | Professional & scientific | 2023 |
| Morgan-Ball Limited | Professional & scientific | 2010 |
| Morgans Automotive Ltd | Professional & scientific | 2022 |
| Morgans Insurance Limited | Financial services | 2012 |
| Moridiyyah ANU Collection Ltd | Wholesale & retail | 2026 |
| Morimana Ltd | Wholesale & retail | 2025 |
| Mork Chocolate UK Limited | Extraterritorial | 2016 |
| Morlan Building Contractors Limited | Construction | 2019 |
| Morley Estates East Anglia Limited | Construction | 1999 |
| Morley Properties Group Limited | Real estate | 2025 |
| Morley Riches & Ablewhite LLP | | 2001 |
| Morley Valentin Properties Limited | Real estate | 2023 |
| Morningstar Autos Limited | Wholesale & retail | 2026 |
| Morph Designs Limited | Construction | 2013 |
| Morris Christian Ltd | Administrative & support | 2025 |
| Morris Leslie Aviation Limited | Transport & logistics | 2013 |
| Morse Installation Services Ltd | Construction | 2007 |