| MJO Properties Ltd | Real estate | 2020 |
| MJP Associates Ltd | Health & social care | 2026 |
| MJR Property Limited | Real estate | 2021 |
| MJS Construction (NE) Ltd | Construction | 2022 |
| MJS Damp Specialist Ltd | Construction | 2022 |
| MJS Properties (NE) Ltd | Construction | 2022 |
| MJT Fabrications Ltd | Manufacturing | 2017 |
| Mjt's Apparel Ltd | Manufacturing | 2026 |
| MK (the Jesmond) Limited | Real estate | 2008 |
| MK Catering NE Events Limited | Hospitality | 2020 |
| MK Catering NE Limited | Hospitality | 2011 |
| MK Facial Aesthetics Ltd | Other services | 2018 |
| MK Properties NE Limited | Real estate | 2019 |
| MK273 Ltd | Health & social care | 2022 |
| Mkkn Ltd | Construction | 2022 |
| MKN Advance Solutions Limited | Professional & scientific | 2024 |
| MKS Welding Services Ltd | Professional & scientific | 2022 |
| Mktg by Design Limited | Professional & scientific | 2020 |
| MKW 2021 Ltd | Real estate | 2021 |
| ML 16 Property Ltd | Real estate | 2025 |
| ML Decorators Limited | Construction | 2025 |
| ML Properties (NE) Ltd | Real estate | 2015 |
| ML School of Music Ltd | Arts & recreation | 2018 |
| ML Wright Ltd | Health & social care | 2022 |
| MLAX1 Limited | Financial services | 2017 |
| MLC Autofix Ltd | Wholesale & retail | 2021 |
| MLC Car Care Ltd | Wholesale & retail | 2023 |
| MLC Rooms Ltd | Construction | 2023 |
| MLD B Limited | Manufacturing | 2025 |
| MLD NE Ltd | Wholesale & retail | 2024 |
| MLK Commercial Limited | Other services | 2022 |
| MLK Electrical Ltd | Construction | 2013 |
| MLK Holdings Group Limited | Financial services | 2022 |
| MLK Residential Limited | Other services | 2022 |
| MLM Consultancy Services Ltd | Professional & scientific | 2020 |
| Mlsa Limited | Hospitality | 2026 |
| Mltw Properties Limited | Real estate | 2020 |
| MLY Industries Ltd | Administrative & support | 2023 |
| MM & Co Accountants Ltd | Professional & scientific | 2024 |
| MM Associates (Bookkeeping) Limited | Professional & scientific | 2012 |
| MM Atex Inspections Ltd | Administrative & support | 2022 |
| MM Audiology Ltd | Health & social care | 2025 |
| MM Consultinghouse Limited | Professional & scientific | 2020 |
| MM Networks Limited | Professional & scientific | 2016 |
| Mm.Access Ltd | Manufacturing | 2024 |
| Mmac Business Consultancy Limited | Information & communication | 2018 |
| MMB Electrical (North East) Limited | Construction | 2021 |
| Mmbritons Limited | Wholesale & retail | 2025 |
| Mmcd Consulting Limited | Administrative & support | 2026 |
| MMF Analytical Limited | Information & communication | 2019 |
| MMG Sports Ltd | Professional & scientific | 2012 |
| MMK General Trading Ltd | Hospitality | 2025 |
| Mmlten Holdings Limited | Financial services | 2026 |
| MMM Estates Limited | Real estate | 2015 |
| MMO Investors Limited Partnership | | 2009 |
| Mmoss Ltd | Health & social care | 2019 |
| MMS Soft Ltd | Information & communication | 2015 |
| Mmsk Foods Ltd | Hospitality | 2023 |
| MN Golf Services Ltd | Arts & recreation | 2026 |
| MNN Estates Ltd | Real estate | 2022 |
| MNQ Ltd | Administrative & support | 2025 |
| MNS Plastering Ltd | Construction | 2022 |
| MO Plaster Ltd | Construction | 2024 |
| MO Pro-Tech Ltd | Professional & scientific | 2026 |
| Mo's Garage Ltd | Wholesale & retail | 2023 |
| Mobile & PC Repairs Limited | Other services | 2020 |
| Mobile Gadgets Ltd | Other services | 2018 |
| Mobile Gadgets NE Ltd | Wholesale & retail | 2025 |
| Mobile Madness UK Ltd | Wholesale & retail | 2018 |
| Mode&Mood Limited | Wholesale & retail | 2025 |
| Modec (Heating and Plumbing) Limited | Wholesale & retail | 1973 |
| Model Boot Camp (MBC) Limited | Education | 2009 |
| Modello Residents Management Company Limited | Households | 2024 |
| Modern Furniture and Lighting Ltd | Wholesale & retail | 2014 |
| Modern Kitchens NE Ltd | Manufacturing | 2026 |
| Modern Lettings NE Ltd | Real estate | 2023 |
| Modest Style Ltd | Wholesale & retail | 2022 |
| Modmira Ltd | Wholesale & retail | 2025 |
| Modnarway 2 Ltd | Hospitality | 2022 |
| Modnarway 3 Ltd | Hospitality | 2024 |
| Modnarway Limited | Hospitality | 2020 |
| Modobloc Construction Ltd | Construction | 2021 |
| Modobloc Foundry Lane Ltd | Construction | 2020 |
| Modobloc Grieveson's Yard Ltd | Construction | 2021 |
| Modobloc Hmos Ltd | Real estate | 2024 |
| Modobloc Ltd | Real estate | 2021 |
| Modobloc Nevilles Cross Limited | Construction | 2021 |
| Modobloc Old Co-Op Building Ltd | Construction | 2021 |
| Modobloc RLC Ltd | Construction | 2021 |
| Modobloc Springfield Limited | Real estate | 2024 |
| Modobloc ST Lawrence RD 2 Ltd | Real estate | 2024 |
| Modobloc ST Lawrence RD Ltd | Construction | 2021 |
| Modobloc Station RD Ltd | Construction | 2021 |
| Modpods Northeast Ltd | Construction | 2025 |
| Modrentra Ltd | Transport & logistics | 2025 |
| Module 3 Limited | Professional & scientific | 2021 |
| Moffat Bond Limited | Extraterritorial | 2013 |
| Moffitt QSE Ltd | Mining & quarrying | 2013 |
| Moh's Property Maintenance/Lettings Ltd | Real estate | 2024 |
| Mohamed Bouzidi Logistics Ltd | Transport & logistics | 2026 |