| Mohamed Hassan Logistics Limited | Transport & logistics | 2025 |
| Mohiuddin Trust | Administrative & support | 2004 |
| Moirs for Mirror and Glass Ltd | Manufacturing | 2025 |
| Moirs Glass & Glazing Ltd | Extraterritorial | 2019 |
| Moja Group Limited | Professional & scientific | 2022 |
| Moja Newcastle Ltd | Hospitality | 2024 |
| Mojako Limited | Health & social care | 2022 |
| Mojo Risin' Publishing Limited | Arts & recreation | 2015 |
| Mokate Property Investments Limited | Real estate | 2018 |
| Mokomboso UK Limited | Professional & scientific | 2022 |
| Mold Consultancy Ltd | Construction | 2018 |
| Mole, the Brand Limited | Wholesale & retail | 2022 |
| Molina Newcastle Ltd | Hospitality | 2024 |
| Molitor Investments | Professional & scientific | 2012 |
| Molly's Kitchen NE CIC | Hospitality | 2024 |
| Momena Ltd | Wholesale & retail | 2024 |
| Moment Hill Ltd | Professional & scientific | 2026 |
| Moment of Truth Well-Being Group Ltd | Professional & scientific | 2019 |
| Moments WE Share Ltd | Wholesale & retail | 2024 |
| Momentum Health and Performance Ltd | Health & social care | 2025 |
| Mona Shah & Partners Global Practice Ltd | Professional & scientific | 2025 |
| Monaco Chefs Ltd | Real estate | 2025 |
| Monapeteet Ltd | Wholesale & retail | 2022 |
| Monark Innovation Studio Ltd | Manufacturing | 2026 |
| Money for Motors North East Ltd | Wholesale & retail | 2025 |
| Money Penny Wealth Management Limited | Financial services | 2021 |
| Monitor Marine (C.P.) Limited | Real estate | 1985 |
| Monitoring Cctv Limited | Administrative & support | 2016 |
| Monkchester Nursery Family Centre | Education | 2006 |
| Monkey and Monkey Enterprises Limited | Arts & recreation | 2026 |
| Monkey Pickles Ltd | Other services | 2024 |
| Monkey Print Limited | Manufacturing | 2015 |
| Monkeyfist Hair Ltd | Other services | 2019 |
| Monkhouse Design Ltd | Professional & scientific | 2024 |
| Monogram Ltd | Arts & recreation | 2014 |
| Monograph LLP | | 2012 |
| Monsieur Crepe Ltd | Hospitality | 2016 |
| Monsoon Kitchen Ltd | Hospitality | 2013 |
| Mont Caly Holdings Limited | Financial services | 2023 |
| Montagu Consulting Limited | Administrative & support | 2025 |
| Montagu Hotels Limited | Construction | 2004 |
| Montagu Properties Limited | Extraterritorial | 1983 |
| Montague Apartments (Whitley Bay) Management Company Limited | Real estate | 2016 |
| Montague Court (Hexham) Residents Management Company Limited | Households | 2025 |
| Montcada Habsburg Limited | Financial services | 2022 |
| Monte Cristo Residential Ltd | Real estate | 2014 |
| Montelago BLU & SON Holdings Ltd | Financial services | 2025 |
| Montizumo Limited | Wholesale & retail | 2015 |
| Montpellier Macro Ltd | Information & communication | 2024 |
| Montra Thai Massage and Spa Ltd | Administrative & support | 2017 |
| Monts Design Ltd | Professional & scientific | 2024 |
| Monucap LLP | | 2021 |
| Monument Gosforth LLP | | 2022 |
| Monument Nicholas CC LLP | | 2021 |
| Monument Nicholas LLP | | 2021 |
| Monument Real Estate Management Limited | Real estate | 2016 |
| Mood 2 Ltd | Information & communication | 2021 |
| Mood Seasons Ltd | Wholesale & retail | 2020 |
| Moon Healthcare Group Limited | Financial services | 2026 |
| Moon JET Group Ltd | Wholesale & retail | 2023 |
| Moon SAL Ltd | Hospitality | 2025 |
| Mooney's Plumbing & Drainage Ltd | Construction | 2019 |
| Moonies Boutique Limited | Other services | 2019 |
| Moonpaper Studio Ltd | Information & communication | 2026 |
| Moore & Whelan Property Limited | Hospitality | 2017 |
| Moore Funeral Services Limited | Other services | 2012 |
| Moore Projects Limited | Real estate | 2022 |
| Moorelec Limited | Extraterritorial | 2016 |
| Moorgate Resources Limited | Information & communication | 2016 |
| Moorlands Care Homes (N.E.) Limited | Health & social care | 2004 |
| Moorlands Holdings (N.E.) Limited | Hospitality | 1987 |
| Moors Medical Services Ltd | Professional & scientific | 2025 |
| Moorside Locksmiths Ltd | Administrative & support | 2020 |
| Moorside Properties (North East) Limited | Real estate | 2007 |
| Moorstone | Financial services | 2013 |
| Moorstone Digital Solutions Ltd | Wholesale & retail | 2026 |
| Moorview Properties Limited | Real estate | 1958 |
| Moozars Ltd | Information & communication | 2022 |
| Moral Limited | Health & social care | 2013 |
| Moral Rebels Ltd | Professional & scientific | 2025 |
| Mordant Estates Limited | Real estate | 2023 |
| Morden Tower Book Room Ltd | Information & communication | 2024 |
| Mordue Scales Ltd | Manufacturing | 2015 |
| More Than This Events Ltd | Hospitality | 2023 |
| Moreland Commercial Services Ltd | Manufacturing | 2022 |
| Morelli Kersey Ltd | Wholesale & retail | 2026 |
| Morespace Conversions (N.E) Ltd | Construction | 2021 |
| Morfose North East Limited | Other services | 2020 |
| Morgale Enterprise Ltd | Information & communication | 2024 |
| Morgan Glenwell (UK) Limited | Professional & scientific | 2012 |
| Morgan Grey Ltd | Real estate | 2007 |
| Morgan Properties (Newcastle) Limited | Other services | 2001 |
| Morgan Residential Limited | Real estate | 2025 |
| Morganflex Ltd | Households | 2023 |
| Moriano Properties Limited | Real estate | 2024 |
| Mornee Jewellery Ltd | Wholesale & retail | 2026 |
| Morning Rescue Ltd | Wholesale & retail | 2025 |
| Morning SIR Productions Ltd | Information & communication | 2024 |
| Morph Clinical Services Limited | Professional & scientific | 2020 |
| Morph Consultancy Ltd | Professional & scientific | 2001 |