| Morrow Choice Limited | Information & communication | 2022 |
| Mors Vincit Omnia Limited | Real estate | 2020 |
| Mortgage Broker North East Limited | Financial services | 2012 |
| Mortgage Select North Ltd | Financial services | 2020 |
| Mortgage Solutions (N/E) Ltd | Financial services | 2018 |
| Mortgages 4 U (NE) Limited | Financial services | 2022 |
| Mortimer Bell International Limited | Administrative & support | 2012 |
| Morton Construction Group Ltd | Construction | 2025 |
| Morton Fraser Limited | Professional & scientific | 2006 |
| Morvareed Construction Ltd | Construction | 2023 |
| Morvareed Limited | Wholesale & retail | 2023 |
| Mosaic Quayside Ltd | Hospitality | 2024 |
| Mosaic TAP Ltd | Hospitality | 2021 |
| Mosedale Gillatt Architects Limited | Professional & scientific | 2002 |
| Mosedale Gillatt Trustees Limited | Administrative & support | 2024 |
| Mosley Express Ltd | Wholesale & retail | 2025 |
| Mosleystreet Express Ltd | Wholesale & retail | 2026 |
| Mossmill Properties Limited | Real estate | 2003 |
| Mossy Rock Brewhouse Ltd | Extraterritorial | 2021 |
| Most Suitable Limited | Wholesale & retail | 2017 |
| Moth Studios Ltd | Arts & recreation | 2017 |
| Mother Mercy Hospitality Ltd | Financial services | 2023 |
| Motherfolk Ltd | Education | 2025 |
| Motionworks Physiotherapy Ltd | Health & social care | 2024 |
| Motivait Holdings Limited | Information & communication | 2015 |
| Motivait Limited | Information & communication | 2015 |
| Motivation in Mainstream Ltd | Education | 2023 |
| Motivation in School Ltd | Education | 2025 |
| Motor Export Ltd | Wholesale & retail | 2016 |
| Motor Factors Limited | Wholesale & retail | 2017 |
| Motor Hub Limited | Wholesale & retail | 2025 |
| Motor Jungle Ltd | Wholesale & retail | 2019 |
| Motor Tech (Shotton) Ltd | Wholesale & retail | 2018 |
| Motorblade Limited | Transport & logistics | 1995 |
| Motorhome Hire Northeast Ltd | Administrative & support | 2021 |
| Motorhomes NE Limited | Wholesale & retail | 2025 |
| Motoring on Limited | Wholesale & retail | 2020 |
| Motorlink Group Ltd | Wholesale & retail | 2025 |
| Motoworld Online Limited | Information & communication | 2024 |
| Motusio Ltd | Administrative & support | 2026 |
| Motyl Studio Community Interest Company | Arts & recreation | 2026 |
| Mount Cottage Ltd | Hospitality | 2025 |
| Mount Gable Estates Limited | Real estate | 2015 |
| Mountain King Limited | Manufacturing | 1996 |
| Mountavenue Investments Limited | Real estate | 2017 |
| Mountfair Consultancy Limited | Other services | 2022 |
| Movade Living Ltd | Real estate | 2026 |
| Movade LLP | | 2022 |
| Movade Properties Ltd | Real estate | 2022 |
| Move on Accountants Ltd | Professional & scientific | 2002 |
| Movement Software UK Limited | Financial services | 2026 |
| Movemymotor 24/7 Ltd | Wholesale & retail | 2023 |
| Movenortheast Ltd | Real estate | 2025 |
| Movesun Limited | Extraterritorial | 2002 |
| Mowbray Advisory Limited | Professional & scientific | 2021 |
| Mowlem and Company (Design) Limited | Wholesale & retail | 2017 |
| Moxon Cole Ltd | Professional & scientific | 2024 |
| MOZ Newcastle Ltd | Wholesale & retail | 2020 |
| Mozs Wholesale Newcastle Limited | Wholesale & retail | 2022 |
| MP Delivery’S Ltd | Transport & logistics | 2025 |
| Mpatonhr Ltd | Administrative & support | 2026 |
| MPK Maxillofacial Ltd | Health & social care | 2025 |
| MPM Consulting Ltd | Professional & scientific | 2025 |
| MPS 6 (Residential) Limited | Real estate | 2018 |
| MPS Fibre Ltd | Information & communication | 2018 |
| Mpsamuels Professional Services Ltd | Information & communication | 2023 |
| Mquad Ltd | Wholesale & retail | 2023 |
| MR Bindi Ltd | Hospitality | 2020 |
| MR Bubbles Mini Valet Centre Ltd | Other services | 2020 |
| MR Bubbles Mini Valet Centre NE Ltd | Other services | 2022 |
| MR Burger NCL Ltd | Hospitality | 2025 |
| MR Dumitru Logistics Limited | Transport & logistics | 2025 |
| MR Green Ltd | Wholesale & retail | 2024 |
| MR Health, Safety and Compliance Consultancy Limited | Professional & scientific | 2026 |
| MR James P Holland Limited | Health & social care | 2009 |
| MR Jessop Limited | Financial services | 2015 |
| MR Joinery Newcastle Ltd | Manufacturing | 2019 |
| MR Smoke NE Ltd | Wholesale & retail | 2024 |
| MR Tilly's Male Grooming Limited | Other services | 2016 |
| MR Tillys Heaton Limited | Other services | 2023 |
| MR Tillys Studio Limited | Other services | 2025 |
| MR Wolf Urban Spices Ltd | Wholesale & retail | 2018 |
| MR. Tj's Limited | Hospitality | 2023 |
| Mr.Reddy Stores UK Ltd | Wholesale & retail | 2025 |
| Mr.Vapey Ltd | Wholesale & retail | 2026 |
| MR7TRADE Ltd | Information & communication | 2023 |
| MRA Property Investments Limited | Real estate | 2002 |
| MRA Property Limited | Real estate | 2018 |
| MRB Engineering Services Limited | Professional & scientific | 2018 |
| MRB Inspired Scents Limited | Manufacturing | 2021 |
| MRD Travel and Tourism Ltd | Wholesale & retail | 2025 |
| Mrdoit Ltd | Construction | 2026 |
| Mref III Newcastle Operations Limited | Real estate | 2017 |
| MRH Electrical (NE) Ltd | Administrative & support | 2017 |
| MRH Leisure Limited | Hospitality | 2023 |
| MRJ Travels Ltd | Transport & logistics | 2021 |
| MRK3 Ltd | Wholesale & retail | 2024 |
| MRM Building Services Ltd | Construction | 2018 |
| MRM Electrical Solutions Limited | Construction | 2009 |
| MRM Site Management Ltd | Construction | 2024 |